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The oral mucosa is constantly exposed to a plethora of stimuli including food antigens, commensal microbiota and pathogens, requiring distinct immune responses. We previously reported that human oral epithelial cells (OECs) suppress immune responses to bacteria, using H413 and TR146 OEC lines and primary OECs in co-culture with dendritic cells (DCs) and T cells (OEC-conditioned cells). OECs reduced DCs expression of CD80/CD86 and IL-12/TNFα release and impaired T cell activation. Here, we further evaluated the immunosuppression by these OECs and investigated the underlying mechanisms. OEC-conditioned DCs did not induce CD4 T cell polarization towards Treg, judging by the absence of FoxP3 expression. OECs also repressed T-bet/IFNγ expression in CD4 and CD8 T cells activated by DCs or anti-CD3/CD28 antibodies. This inhibition depended on OEC:T cell ratio and IFNγ repression occurred at the transcriptional level. Time-lapse experiments showed that OECs inhibited early steps of T cell activation, consistent with OECs inability to suppress T cells stimulated with PMA/ionomycin. Blocking CD40/CD40L, CD58/CD2 and PD-L1/PD-1 interactions with specific antibodies did not disrupt T cell suppression by OECs. However, preventing prostaglandin E2 (PGE2) synthesis or blocking PGE2 binding to the cognate EP2/EP4 receptors, restored IFNγ and TNFα production in OEC-conditioned T cells. Finally, treating OECs with poly(I:C), which simulates viral infections, limited T cell suppression. Overall, these results point to an inherent ability of OECs to suppress immune responses, which can nonetheless be eluded when OECs are under direct assault., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sanchez-Trincado, Pelaez-Prestel, Lafuente and Reche.)

Complex autoimmune diseases are sexually dimorphic. An interplay between predisposing genetics and sex-related factors probably controls the sex discrepancy in the immune response, but the underlying mechanisms are unclear. Here we positionally identify a polymorphic estrogen receptor binding site that regulates Cd2 expression, leading to female-specific differences in T cell-dependent mouse models of autoimmunity. Female mice with reduced Cd2 expression have impaired autoreactive T cell responses. T cells lacking Cd2 costimulation upregulate inhibitory Lag-3. These findings help explain sexual dimorphism in human autoimmunity, as we find that CD2 polymorphisms are associated with rheumatoid arthritis and 17-β-estradiol-regulation of CD2 is conserved in human T cells. Hormonal regulation of CD2 might have implications for CD2-targeted therapy, as anti-Cd2 treatment more potently affects T cells in female mice. These results demonstrate the relevance of sex-genotype interactions, providing strong evidence for CD2 as a sex-sensitive predisposing factor in autoimmunity., (© 2021. The Author(s).)

The glycoprotein CD58, also known as lymphocyte-function antigen 3 (LFA-3), is a costimulatory receptor distributed on a broad range of human tissue cells. Its natural ligand CD2 is primarily expressed on the surface of T/NK cells. The CD2-CD58 interaction is an important component of the immunological synapse (IS) that induces activation and proliferation of T/NK cells and triggers a series of intracellular signaling in T/NK cells and target cells, respectively, in addition to promoting cell adhesion and recognition. Furthermore, a soluble form of CD58 (sCD58) is also present in cellular supernatant in vitro and in local tissues in vivo . The sCD58 is involved in T/NK cell-mediated immune responses as an immunosuppressive factor by affecting CD2-CD58 interaction. Altered accumulation of sCD58 may lead to immunosuppression of T/NK cells in the tumor microenvironment, allowing sCD58 as a novel immunotherapeutic target. Recently, the crucial roles of costimulatory molecule CD58 in immunomodulation seem to be reattracting the interests of investigators. In particular, the CD2-CD58 interaction is involved in the regulation of antiviral responses, inflammatory responses in autoimmune diseases, immune rejection of transplantation, and immune evasion of tumor cells. In this review, we provide a comprehensive summary of CD58 immunobiology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhang, Liu, Yang and Liao.)

Female breast cancer (BCa) is the most commonly occurring cancer worldwide. The tumor microenvironment (TME) plays an essential role in tumor invasion, angiogenesis, unlimited proliferation, and even immune escape, but we know little about the TME of BCa. In this study, we aimed to find a TME-related biomarker for BCa, especially for invasive breast carcinoma (BRCA), that could predict prognosis and immunotherapy efficacy. Based on RNA-seq transcriptome data and the clinical characteristics of 1222 samples (113 normal and 1109 tumor samples) from The Cancer Genome Atlas (TCGA) database, we used the ESTIMATE algorithm to calculate the ImmuneScore and StromalScore and then identified differentially expressed genes (DEGs) between the high and low ImmuneScore groups and the high and low StromalScore groups. Thereafter, a protein-protein interaction (PPI) network analysis and univariate Cox regression analyses of overall survival were used to identify potential key genes. Five candidate genes were identified, comprising CD2, CCL19, CD52, CD3E, and ITK. Thereafter, we focused on CD2, analyzing CD2 expression and its association with survival. CD2 expression was associated with tumor size (T stage) to some extent, but not with overall TNM stage, lymph node status (N stage), or distant metastasis (M stage). High CD2 expression was associated with longer survival. METABRIC data were used to validate the survival result (n = 276). Gene set enrichment analysis (GSEA) showed that the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were significantly associated with high CD2 expression were mainly immune-related pathways. Furthermore, CD2 expression was correlated with 16 types of tumor-infiltrating immune cells (TICs). Hence, CD2 might be a novel biomarker in terms of molecular typing, and it may serve as a complementary approach to TNM staging to improve clinical outcome prediction for BCa patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Meng, Zhang and Liu.)

The glycoprotein CD2 is expressed on T and NK cells and contributes to cell-cell conjugation, agonistic signaling and actin cytoskeleton rearrangement. CD2 has previously been shown to have an important function in natural NK cell cytotoxicity but to be expendable in antibody-mediated cytotoxicity. Siplizumab is a monoclonal anti-CD2 IgG1 antibody that is currently undergoing clinical trials in the field of transplantation. This study investigated the effect of CD2 binding and Fc γ receptor binding by siplizumab (Fc-active) and Fc-silent anti-CD2 monoclonal antibodies in allogeneic mixed lymphocyte reaction and autologous lymphocyte culture. Further, induction of NK cell fratricide and inhibition of natural cytotoxicity as well as antibody-dependent cytotoxicity by these agents were assessed. Blockade of CD2 via monoclonal antibodies in the absence of Fc γ receptor binding inhibited NK cell activation in allogeneic mixed lymphocyte reaction. In contrast, siplizumab increased NK cell activation in both mixed lymphocyte reaction and autologous lymphocyte culture due to FcγRIIIA binding. However, experiments using purified NK cells did not show an inhibitory effect of CD2 blockade on natural cytotoxicity or antibody-dependent cytotoxicity. Lastly, it was shown that siplizumab induces NK cell fratricide. Concluding, siplizumab is a promising biopharmaceutical drug candidate for depletion of T and NK cells with minimal off-target effects., Competing Interests: CB, FS, FC, SB, EB and DB are employees of ITB Med AB. SB, EB, and DB own shares in ITB Med AB. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Binder, Sellberg, Cvetkovski, Berg, Berglund and Berglund.)

The glycoprotein CD2 is a costimulatory receptor expressed mainly on T and NK cells that binds to LFA3, a cell surface protein expressed on e.g., antigen-presenting cells. CD2 has an important role in the formation and organization of the immunological synapse that is formed between T cells and antigen-presenting cells upon cell-cell conjugation and associated intracellular signaling. CD2 expression is upregulated on memory T cells as well as activated T cells and plays an important role in activation of memory T cells despite the coexistence of several other costimulatory pathways. Anti-CD2 monoclonal antibodies have been shown to induce immune modulatory effects in vitro and clinical studies have proven the safety and efficacy of CD2-targeting biologics. Investigators have highlighted that the lack of attention to the CD2/LFA3 costimulatory pathway is a missed opportunity . Overall, CD2 is an attractive target for monoclonal antibodies intended for treatment of pathologies characterized by undesired T cell activation and offers an avenue to more selectively target memory T cells while favoring immune regulation., (Copyright © 2020 Binder, Cvetkovski, Sellberg, Berg, Paternina Visbal, Sachs, Berglund and Berglund.)

Understanding the costimulatory signaling that enhances the activity of cytotoxic T cells (CTLs) could identify potential targets for immunotherapy. Here, we report that CD2 costimulation plays a critical role in target cell killing by freshly isolated human CD8 + T cells, which represent a challenging but valuable model to gain insight into CTL biology. We found that CD2 stimulation critically enhanced signaling by the T cell receptor in the formation of functional immune synapses by promoting the polarization of lytic granules toward the microtubule-organizing center (MTOC). To gain insight into the underlying mechanism, we explored the CD2 signaling network by phosphoproteomics, which revealed 616 CD2-regulated phosphorylation events in 373 proteins implicated in the regulation of vesicular trafficking, cytoskeletal organization, autophagy, and metabolism. Signaling by the master metabolic regulator AMP-activated protein kinase (AMPK) was a critical node in the CD2 network, which promoted granule polarization toward the MTOC in CD8 + T cells. Granule trafficking was driven by active AMPK enriched on adjacent lysosomes, revealing previously uncharacterized signaling cross-talk between vesicular compartments in CD8 + T cells. Our results thus establish CD2 signaling as key for mediating cytotoxic killing and granule polarization in freshly isolated CD8 + T cells and strengthen the rationale to choose CD2 and AMPK as therapeutic targets to enhance CTL activity., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: The assessment of minimal residual disease (MRD) by flow cytometry (FC) has a prognostic impact in acute myeloid leukemia (AML), despite the low sensitivity in predicting relapse. Nonetheless, the role of leukemic-associated immunophenotypes (LAIPs)-related specificity on the sensitivity of MRD has not been clarified yet. In this respect, we accomplished this study., Methods: LAIP-frequencies of bone marrow samples from healthy donors and patients after treatment were quantified and subdivided in "categories of specificity" named as: "strong," "good," and "weak." At the following, the diagnostic performance of MRD was investigated in terms of sensitivity, specificity, predictive values, likelihood ratio (LR)., Results: "Strong" LAIPs were identified by CD7, CD2, CD4, and CD56 markers while "weak" LAIPs, independently of coexpressed markers, were mainly observed in CD33+ cells. MRD identified patients with significantly low DFS and OS but showed a low sensitivity in predicting relapse. Interestingly, majority of recurrences was noticed in patients with two LAIPs and lacking of "strong" LAIPs or only with one "good" LAIP. Thus, only patients showing one "strong" or two "good" LAIPs were considered suitable for MRD monitoring and selected to be further investigated. In this subset, positive MRD predicted a poor prognosis. Moreover, a higher sensitivity, negative predictive value (NPV) and LR- were observed after comparison with the previous series., Conclusions: These data highlight the relevant role of LAIP classification in "categories of specificity" in improving the sensitivity of MRD as assessed by FC., (© 2019 International Clinical Cytometry Society.)

Background Aims: Key obstacles in human iNKT cell translational research and immunotherapy include the lack of robust protocols for dependable expansion of human iNKT cells and the paucity of data on phenotypes in post-expanded cells., Methods: We delineate expansion methods using interleukin (IL)-2, IL-7 and allogeneic feeder cells and anti-CD2/CD3/CD28 stimulation by which to dependably augment Th2 polarization and direct cytotoxicity of human peripheral blood CD3 + Vα24 + Vβ11 + iNKT cells., Results: Gene and protein expression profiling demonstrated augmented Th2 cytokine secretion (IL-4, IL-5, IL-13) in expanded iNKT cells stimulated with anti-CD2/CD3/CD28 antibodies. Cytotoxic effector molecules including granzyme B were increased in expanded iNKT cells after CD2/CD3/CD28 stimulation. Direct cytotoxicity assays using unstimulated expanded iNKT cell effectors revealed α-galactosyl ceramide (α-GalCer)-dependent killing of the T-ALL cell line Jurkat. Moreover, CD2/CD3/CD28 stimulation of expanded iNKT cells augmented their (α-GalCer-independent) killing of Jurkat cells. Co-culture of expanded iNKT cells with stimulated responder cells confirmed contact-dependent inhibition of activated CD4 + and CD8 + responder T cells., Discussion: These data establish a robust protocol to expand and novel pathways to enhance Th2 cytokine secretion and direct cytotoxicity in human iNKT cells, findings with direct implications for autoimmunity, vaccine augmentation and anti-infective immunity, cancer immunotherapy and transplantation., (Copyright © 2020 International Society for Cell and Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Background: Pediatric mastocytosis differs from adult mastocytosis in its presentation and clinical course. However, the data regarding the immunophenotypic characterization of mast cells in children are limited. Our objective was to evaluate the immunophenotype of mast cells in pediatric mastocytosis and correlate it with the clinical course., Methods: Biopsy specimens of children with cutaneous mastocytosis were retrieved from the institutions of pathology and were stained for CD25, CD2, and CD30. The percentage of mast cells and the staining intensity were correlated with the clinical data., Results: Twenty-five biopsy specimens were included in the study. Patients' average age was 15.4 at presentation and 37.5 months at biopsy performance. Clinical presentations included maculopapular cutaneous mastocytosis in 79% and mastocytoma in 21% of cases. CD25, CD2, and CD30 were positive in 60%, 44%, and 84% of the biopsy specimens, respectively. The staining score was significantly higher for CD30 as compared to those for CD25 and CD2 (P = 0.02). No correlation was found between the immunophenotype and the clinical form or course of disease., Conclusions: Our results confirm that CD30 is a sensitive marker for pediatric-onset mastocytosis. Nevertheless, its expression does not correlate with clinical subtype or clinical course. The sensitivity of CD25 is higher than that of CD2 in skin lesions., (© 2019 Wiley Periodicals, Inc.)

Elimination of the latent HIV reservoir remains the biggest hurdle to achieve HIV cure. In order to specifically eliminate HIV infected cells they must be distinguishable from uninfected cells. CD2 was recently identified as a potential marker enriched in the HIV-1 reservoir on CD4+ T cells, the largest, longest-lived and best-characterized constituent of the HIV reservoir. We previously proposed to repurpose FDA-approved alefacept, a humanized α-CD2 fusion protein, to reduce the HIV reservoir in CD2hi CD4+ memory T cells. Here, we show the first evidence that alefacept can specifically target and reduce CD2hi HIV infected cells in vitro . We explore a variety of natural killer (NK) cells as mediators of antibody-dependent cell-mediated cytotoxicity (ADCC) including primary NK cells, expanded NK cells as well as the CD16 transduced NK-92 cell line which is currently under study in clinical trials as a treatment for cancer. We demonstrate that CD16.NK-92 has a natural preference to kill CD2hi CD45RA- memory T cells, specifically CD45RA- CD27+ central memory/transitional memory (T CM/TM ) subset in both healthy and HIV + patient samples as well as to reduce HIV DNA from HIV + samples from donors well controlled on antiretroviral therapy. Lastly, alefacept can combine with CD16.NK-92 to decrease HIV DNA in some patient samples and thus may yield value as part of a strategy toward sustained HIV remission.

Introduction: Impaired proliferation and production of IL2 are the hallmarks of experimental T cell tolerance. However, in most autoimmune diseases, auto-reactive T cells do not display hyper proliferation, but inflammatory phenotypes., Methods: We have now demonstrated that the transcription factors Egr2 and 3 are important for the control of inflammatory cytokine production by tolerant T cells, but not for tolerance induction., Results: In the absence of Egr2 and 3, T cell tolerance, as measured by impaired proliferation and production of IL2, can still be induced, but tolerant T cells produced high levels of inflammatory cytokines. Egr2 and 3 regulate expression of differentiation repressors and directly inhibit T-bet function in T cells. Indeed, decreased expression of differentiation repressors, such as Id3 and Tcf1, and increased expression of inflammatory transcription factors, such as RORγt and Bhlhe40 were found in Egr2/3 deficient T cells under tolerogenic conditions. In addition, T-bet was co-expressed with Egr2 in tolerant T cells and Egr2/3 defects leads to production of high levels of IFNγ in tolerant T cells., Conclusions: Our findings demonstrated that despite impaired proliferation and IL2 production, tolerant T cells can display inflammatory responses in response to antigen stimulation and this is controlled at least partly by Egr2 and 3., (© 2018 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.)

Lineage-specific Cre Tg mice are widely used to delineate the functions of genes in a tissue-specific manner. Several T-cell-specific promoter cassettes have been developed; however, the activities of those promoters in non-T cells have not been investigated extensively. Here, we report that CD2-Cre-mediated deletion of Erk proteins by generating CD2-Cre × Erk1-/-Erk2flox/flox (Erk∆CD2-Cre) mice results in abnormal cartilage hyperplasia. Histological analysis revealed that this abnormality is caused by aberrant hyperplasia of chondrocytes. The presence of Erk-deficient T cells is not required for this chondroma formation, as it was similarly observed in the absence of T cells in a CD3ε-deficient background. In addition, adoptive transfer of bone marrow cells from Erk∆CD2-Cre mice to wild-type recipients did not cause chondroma formation, suggesting that Erk-deficient non-immune cells are responsible for this abnormality. By tracing Cre-expressed tissues using a ROSA26-STOP-RFP allele, we found that the chondroma emitted RFP fluorescence, indicating that functional Cre is expressed in hyperplastic chondrocytes in Erk∆CD2-Cre mice. Furthermore, RFP+ chondrocytes were also found in an Erk-sufficient background, albeit without aberrant growth. These results suggest that unexpected expression of CD2-driven Cre in chondrocytes generates Erk-deficient chondrocytes, resulting in hyperplastic cartilage formation. Recently, two independent reports showed that CD4-Cre-mediated Ras-Erk signaling ablation led to similar abnormal cartilage formation (Guittard, G., Gallardo, D. L., Li, W. et al. 2017. Unexpected cartilage phenotype in CD4-Cre-conditional SOS-deficient mice. Front. Immunol. 8:343; Wehenkel, M., Corr, M., Guy, C. S. et al. 2017. Extracellular signal-regulated kinase signaling in CD4-expressing cells inhibits osteochondromas. Front. Immunol. 8:482). Together with these reports, our study suggests that an unexpected link exists between T-like cell and chondrocyte lineages during ontogeny., (© The Japanese Society for Immunology. 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Xenotransplantation from pigs has been advocated as a solution to the perennial shortage of donated human organs and tissues. CRISPR/Cas9 has facilitated the silencing of genes in donor pigs that contribute to xenograft rejection. However, the generation of modified pigs using second-generation nucleases with much lower off-target mutation rates than Cas9, such as FokI-dCas9, has not been reported. Furthermore, there have been no reports on the use of CRISPR to knock protective transgenes into detrimental porcine genes. In this study, we used FokI-dCas9 with two guide RNAs to integrate a 7.1 kilobase pair transgene into exon 9 of the GGTA1 gene in porcine fetal fibroblasts. The modified cells lacked expression of the αGal xenoantigen, and secreted an anti-CD2 monoclonal antibody encoded by the transgene. PCR and sequencing revealed precise integration of the transgene into one allele of GGTA1, and a small deletion in the second allele. The cells were used for somatic cell nuclear transfer to generate healthy male knock-in piglets, which did not express αGal and which contained anti-CD2 in their serum. We have therefore developed a versatile high-fidelity system for knocking transgenes into the pig genome for xenotransplantation purposes.

The effect of different concentrations of the glucocorticoid (GC) methylprednisolone (MP) on CD4+CD95+HLA-DR+ T-cells and their ability to produce proinflammatory mediators in cultures of TCR-stimulated CD3+CD45RO+ T-lymphocytes in the in vitro system was investigated. T cells were obtained from healthy donors and patients with rheumatoid arthritis (RA).Under conditions of TCR-activation, MP increased the number of CD4+HLA-DR+CD95+ cells in CD3+CD45RO+ cultures obtained from RA patients and did not change their content in the control group. In general, MP decreased production of proinflammatory factors (IFN-, IL-2, IL-17, IL-21 and TNF-) by TCR-activated CD3+CD45RO+ cells from healthy donors and RA, consistent with the overall immunosuppressive mechanism of GC action. The correlation between CD4+CD45RO+HLA-DR+CD95+ T-cell contents and parameters reflecting production of proinflammatory mediators (IL-17, IL-21 and TNF-) in RA patients indicates maintenance of the pro-inflammatory potential of this T-cell population exposed to GC action. We suggest that relative resistance of CD4+CD45RO+CD95+HLA-DR+ T-cells of RA patients to the suppressor effect of GC leads to maintenance and even enhancement in the functional capacities of autoreactive cells in the pathogenesis of RA.

It is very difficult to cure pregnant females suffering from infections, because of the risk which might occur during treatment by several, even herbal, medications. Many of these substances, among them extracts from plants, have antimicrobial, anti-inflammatory and immunostimulatory properties owing to their polyphenols content, but also may reveal unwanted effects on the fetal development because of their anti-angiogenic properties. The aim of the present study was to elucidate whether daily feeding pregnant and nursing mice 0.2 mg/kg epigallocatechin (EGC), previously recognized as angiogenesis inhibitor, may lead to abnormalities in morphology of spleen and in some parameters of immune function of their adult, 6-week old progeny. Morphometry of EGC offspring spleens revealed lower number of lymphatic nodules and their larger diameter than those found in the control offspring. Cellularity of spleens was lower in EGC offspring than in the controls. Cytometric analysis showed that this decline concerns lymphocytes with CD335 (p<0.001), CD19 (p<0.01) and CD4 (p<0.05) markers. No differences were observed in the humoral response to the immunization with SRBC, and in the proliferative response of splenocytes to mitogens PHA, ConA and LPS.

Objectives: Systemic sclerosis (SSc) is a rare autoimmune disease (AID) with a complex genetic etiology. Evidence for a shared pathogenesis across AIDs is given by the well-known pleiotropism of autoimmune genes. Recently, several unbiased approaches have identified an association between polymorphisms of the CD2 gene, and rheumatoid arthritis (RA) susceptibility. The objective of this study was to investigate whether CD2 polymorphisms are associated with SSc., Methods: Two SNPs of CD2, rs624988 and rs798036, were genotyped in a total of 1,786 SSc patients and 2,360 healthy individuals from two European populations (France and Italy). Meta-analyses were performed to assess whether an association exists between CD2 polymorphisms or haplotypes and SSc or its main subtypes., Results: The combined analyses revealed an association between the rs624988 A allele and SSc susceptibility: padj=0.023, OR=1.14 (95%CI 1.04-1.25). Single marker analysis did not reveal any association between rs798036 and SSc. Haplotype analysis identified that the A-T haplotype, previously described in RA, was associated with higher susceptibility for SSc (padj=0.029, OR=1.14, 95%CI 1.04-1.25) and with the positive anti-centromere antibody sub-group of SSc patients (padj=0.009, OR=1.19 95%CI 1.07-1.32). Genotype-mRNA expression correlations revealed that the CD2 risk haplotype was associated with decreased CD2 mRNA expression in SSc patients., Conclusions: Our study establishes CD2 as a new susceptibility factor for SSc, in a European Caucasian population, confirming the sharing of autoimmune risk factors by SSc and RA.

Background: Systemic mastocytosis (SM) is a diagnosis made using clinical, laboratory, and histologic parameters. Aberrant CD2 and/or CD25 expression on mast cells provides one minor criterion for a diagnosis of SM. To validate a tube (CD45/CD117/CD2/CD25) for mast cell evaluation, flow cytometry (FC) on residual material from marrow aspirates samples submitted to the hematopathology laboratory was performed., Methods: Samples evaluated (n = 98) had no clinical or morphologic suspicion for SM. Samples were excluded if there was history of a myeloid stem cell neoplasm. Ten documented cases of SM were evaluated for comparison., Results: Among cases without history of SM, 17.3% (n = 17) showed expression of CD2 and/or CD25 on ≥10% of the mast cell population (CD25 alone in 14 cases, CD2 alone in 2 cases, both in one case), while 82.6% (n = 81) showed no expression of these antigens. The percentage of mast cells showing aberrant CD2 and/or CD25 expression respectively ranged from 12.1% to 98.8% and 22.2% to 95.7% Interestingly, all of the cases with evidence of aberrant antigen expression on mast cells were collected post-therapy while 22.1% of the negative samples were collected pre-therapy. A cut-off of 60% CD25 expression on mast cells identified all cases of SM while minimizing false positives., Conclusions: These findings demonstrate that aberrant expression of CD2 and/or CD25 may be seen on mast cells outside of the setting of SM. The data suggests that this phenomenon may be seen more commonly following chemotherapy and that FC of mast cells should be interpreted with caution in the post-chemotherapy setting. © 2015 International Clinical Cytometry Society., (© 2015 International Clinical Cytometry Society.)

Infection by human cytomegalovirus (HCMV) leads to NKG2C-driven expansion of adaptive natural killer (NK) cells, contributing to host defense. However, approximately 4% of all humans carry a homozygous deletion of the gene that encodes NKG2C (NKG2C(-/-)). Assessment of NK cell repertoires in 60 NKG2C(-/-) donors revealed a broad range of NK cell populations displaying characteristic footprints of adaptive NK cells, including a terminally differentiated phenotype, functional reprogramming, and epigenetic remodeling of the interferon (IFN)-γ promoter. We found that both NKG2C(-) and NKG2C(+) adaptive NK cells expressed high levels of CD2, which synergistically enhanced ERK and S6RP phosphorylation following CD16 ligation. Notably, CD2 co-stimulation was critical for the ability of adaptive NK cells to respond to antibody-coated target cells. These results reveal an unexpected redundancy in the human NK cell response to HCMV and suggest that CD2 provides "signal 2" in antibody-driven adaptive NK cell responses., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

The CRISPR/Cas9 system can be used to mutate target sequences by introduction of double-strand breaks followed by imprecise repair. To test its use for conditional gene editing we generated mice transgenic for CD4 promoter-driven Cas9 combined with guide RNA targeting CD2. We found that within CD4(+) and CD8(+) lymphocytes from lymph nodes and spleen 1% and 0.6% were not expressing CD2, respectively. T cells lacking CD2 carryied mutations, which confirmed that Cas9 driven by cell-type specific promoters can edit genes in the mouse and may thus allow targeted studies of gene function in vivo.

By congenic strain mapping using autoimmune NOD.C57BL/6J congenic mice, we demonstrated previously that the type 1 diabetes (T1D) protection associated with the insulin-dependent diabetes (Idd)10 locus on chromosome 3, originally identified by linkage analysis, was in fact due to three closely linked Idd loci: Idd10, Idd18.1, and Idd18.3. In this study, we define two additional Idd loci--Idd18.2 and Idd18.4--within the boundaries of this cluster of disease-associated genes. Idd18.2 is 1.31 Mb and contains 18 genes, including Ptpn22, which encodes a phosphatase that negatively regulates T and B cell signaling. The human ortholog of Ptpn22, PTPN22, is associated with numerous autoimmune diseases, including T1D. We, therefore, assessed Ptpn22 as a candidate for Idd18.2; resequencing of the NOD Ptpn22 allele revealed 183 single nucleotide polymorphisms with the C57BL/6J (B6) allele--6 exonic and 177 intronic. Functional studies showed higher expression of full-length Ptpn22 RNA and protein, and decreased TCR signaling in congenic strains with B6-derived Idd18.2 susceptibility alleles. The 953-kb Idd18.4 locus contains eight genes, including the candidate Cd2. The CD2 pathway is associated with the human autoimmune disease, multiple sclerosis, and mice with NOD-derived susceptibility alleles at Idd18.4 have lower CD2 expression on B cells. Furthermore, we observed that susceptibility alleles at Idd18.2 can mask the protection provided by Idd10/Cd101 or Idd18.1/Vav3 and Idd18.3. In summary, we describe two new T1D loci, Idd18.2 and Idd18.4, candidate genes within each region, and demonstrate the complex nature of genetic interactions underlying the development of T1D in the NOD mouse model., (Copyright © 2015 The Authors.)

CD2 and CD58 are two important costimulatory molecules involved in generating the signal II required for normal immune signaling. However, this interaction can be targeted to be of benefit in cases of abnormal immune signaling seen in autoimmune diseases. Our objective in this study was to design a peptidomimetic (compound 7) based on a β-strand structure of the adhesion domain of CD2 protein to inhibit CD2-CD58 protein-protein interaction and its effect on immunomodulation in the collagen-induced arthritis (CIA) model. The ability of compound 7 to bind to CD58 protein was assessed using flow cytometry. The effect of compound 7 on modulating the immune response was evaluated in an autoimmune disease using CIA in mice. The stability of compound 7 was evaluated in mouse serum using mass spectrometry. Antibody (Ab) binding inhibition studies suggested that compound 7 binds to CD58 protein. Compound 7 was successful in modulating immune responses when administered in the CIA mouse model along with reducing anti-collagen Ab levels and decreasing the level of interferon gamma (IFN-γ) relative to control treatments. Compound 7 was found to be nonimmunogenic and stable in mouse serum up to 48 h. Results suggest that compound 7 can serve as a lead compound for immunomodulation, and could be a therapeutic agent for the autoimmune disease rheumatoid arthritis (RA)., (© 2015 Wiley Periodicals, Inc.)

Transfusion-related alloimmunization is a potent barrier to the engraftment of allogeneic hematopoietic stem cells in patients with nonmalignant diseases (NMDs). Memory T cells, which drive alloimmunization, are relatively resistant to commonly used conditioning agents. Alefacept, a recombinant leukocyte function antigen-3/IgG1 fusion protein, targets CD2 and selectively depletes memory versus naive T cells. Three multiply transfused pediatric patients with NMD received a short course of high-dose i.v. alefacept (.25 mg/kg/dose on days -40 and -9 and .5 mg/kg/dose on days -33, -26, -19, and -12) before undergoing unrelated allogeneic transplant in the setting of reduced-intensity pretransplant conditioning and calcineurin inhibitor-based post-transplant graft-versus-host disease (GVHD) prophylaxis. Alefacept infusions were well tolerated in all patients. Peripheral blood flow cytometry was performed at baseline and during and after alefacept treatment. As expected, after the 5 weekly alefacept doses, each patient demonstrated selective loss of CD2(hi)/CCR7(-)/CD45RA(-) effector memory (Tem) and CD2(hi)/CCR7(+)/CD45RA(-) central memory (Tcm) CD4(+) and CD8(+) T cells with relative preservation of the CD2(lo) Tem and Tcm subpopulations. In addition, depletion of CD2(+) natural killer (NK) cells also occurred. Neutrophil recovery was rapid, and all 3 patients had 100% sorted (CD3/CD33) peripheral blood donor chimerism by day +100. Immune reconstitution (by absolute neutrophil, monocyte, and lymphocyte counts) was comparable with a cohort of historical control patients. All 3 patients developed GVHD but are all now off immune suppression and >2 years post-transplant with stable full-donor engraftment. These results suggest that alefacept at higher dosing can deplete both memory T cells and NK cells and that incorporating CD2-targeted depletion into a reduced-intensity transplant regimen is feasible and safe in heavily transfused patients., (Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Primate and rodent NK cells form highly heterogeneous lymphocyte populations owing to the differential expression of germline-encoded receptors. Many of these receptors are polymorphic and recognize equally polymorphic determinants of MHC class I. This diversity can lead to individuals carrying NK cells with different specificities. Cattle have an unusually diverse repertoire of NK cell receptor genes predicted to encode receptors that recognize MHC class I. To begin to examine whether this genetic diversity leads to a diverse NK cell population, we isolated peripheral NK cells from cattle with different MHC homozygous genotypes. Cytokine stimulation differentially influenced the transcription of five receptors at the cell population level. Using dilution cultures, we found that a further seven receptors were differentially transcribed, including five predicted to recognize MHC class I. Moreover, there was a statistically significant reduction in killer cell lectin-like receptor mRNA expression between cultures with different CD2 phenotypes and from animals with different MHC class I haplotypes. This finding confirms that cattle NK cells are a heterogeneous population and reveals that the receptors creating this diversity are influenced by the MHC. The importance of this heterogeneity will become clear as we learn more about the role of NK cells in cattle disease resistance and vaccination., (Copyright © 2015 The Authors.)

The binding of the lymphocyte specific protein tyrosine kinase (Lck) to T cell co-receptors is required for T cell development and activation. In mammals, Lck initiates signal transduction by binding to CD4 and CD8 co-receptors and phosphorylating ITAMs in the cytoplasmic tail of the CD3 molecules and the ζ chains. In addition, Lck can also bind to the adhesion molecule CD2 and trigger T cell activation. In this study, Lck and CD2 homologs were identified and characterized in channel catfish, Ictalurus punctatus. Lck and CD2 mRNAs were specifically expressed by clonal T cell lines, including both CD4(+) and CD4(-)CD8(-) CTL lines, and in mixed lymphocyte cultures (MLC). Western blot analyses using anti-trout Lck and anti-human p-Lck antibodies demonstrated that Lck protein is expressed in catfish clonal CTL and is phosphorylated at a conserved tyrosine residue. Because of the lack of CD8(+) CTL lines as well as the absence of CD8 message in MLC, we performed magnetic bead binding assays to correlate CD2, CD4, and CD8 co-receptor expression with Lck binding ability. Recombinant Lck reproducibly bound to CD2, CD4-1, and CD4-2, but not to CD8α or CD8β. These data provide one possible explanation for the apparent low numbers of CD8(+) CTL and the presence of CD4(+) and CD4(-)CD8(-)CD2(+) CTL in catfish., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The clinical course of autoimmune and infectious disease varies greatly, even between individuals with the same condition. An understanding of the molecular basis for this heterogeneity could lead to significant improvements in both monitoring and treatment. During chronic infection the process of T-cell exhaustion inhibits the immune response, facilitating viral persistence. Here we show that a transcriptional signature reflecting CD8 T-cell exhaustion is associated with poor clearance of chronic viral infection, but conversely predicts better prognosis in multiple autoimmune diseases. The development of CD8 T-cell exhaustion during chronic infection is driven both by persistence of antigen and by a lack of accessory 'help' signals. In autoimmunity, we find that where evidence of CD4 T-cell co-stimulation is pronounced, that of CD8 T-cell exhaustion is reduced. We can reproduce the exhaustion signature by modifying the balance of persistent stimulation of T-cell antigen receptors and specific CD2-induced co-stimulation provided to human CD8 T cells in vitro, suggesting that each process plays a role in dictating outcome in autoimmune disease. The 'non-exhausted' T-cell state driven by CD2-induced co-stimulation is reduced by signals through the exhaustion-associated inhibitory receptor PD-1, suggesting that induction of exhaustion may be a therapeutic strategy in autoimmune and inflammatory disease. Using expression of optimal surrogate markers of co-stimulation/exhaustion signatures in independent data sets, we confirm an association with good clinical outcome or response to therapy in infection (hepatitis C virus) and vaccination (yellow fever, malaria, influenza), but poor outcome in autoimmune and inflammatory disease (type 1 diabetes, anti-neutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosus, idiopathic pulmonary fibrosis and dengue haemorrhagic fever). Thus, T-cell exhaustion plays a central role in determining outcome in autoimmune disease and targeted manipulation of this process could lead to new therapeutic opportunities.

A substantial proportion of CD8(+) T cells in adults lack the expression of the CD28 molecule, and the aging of the immune system is associated with a steady expansion of this T cell subset. CD28(-)CD8(+) T cells are characterized by potent effector functions but impaired responses to antigenic challenge. CD28 acts as the primary T cell costimulatory receptor, but there are numerous additional receptors that can costimulate the activation of T cells. In this study, we have examined such alternative costimulatory pathways regarding their functional role in CD28(-)CD8(+) T cells. Our study showed that most costimulatory molecules have a low capacity to activate CD28-deficient T cells, whereas the engagement of the CD2 molecule by its ligand CD58 clearly costimulated proliferation, cytokine production, and effector function in this T cell subset. CD58 is broadly expressed on APCs including dendritic cells. Blocking CD58 mAb greatly reduced the response of human CD28(-)CD8(+) T cells to allogeneic dendritic cells, as well as to viral Ags. Our results clearly identify the CD58/CD2 axis as the primary costimulatory pathway for CD8 T cells that lack CD28. Moreover, we show that engagement of CD2 amplifies TCR signals in CD28(-)CD8(+) T cells, demonstrating that the CD2-CD58 interaction has a genuine costimulatory effect on this T cell subset. CD2 signals might promote the control of viral infection by CD28(-)CD8(+) T cells, but they might also contribute to the continuous expansion of CD28(-)CD8(+) T cells during chronic stimulation by persistent Ag., (Copyright © 2015 by The American Association of Immunologists, Inc.)

In this study, we observed changes in CD4(+) CD25(+) Foxp3(+) Treg expression in rats with osteoarthritis (OA) to explore the role that CD4(+) CD25(+) Foxp3(+) Treg plays in the decline in the condition of OA rats. Thirty rats were randomly divided into 2 groups equally and OA was induced in rats in the model group by injection of papain and l-cysteine into the right knee joint. Cartilage lesions were scored by the modified Mankin scale; pulmonary function was assessed by spirometry; interleukin (IL)-17 and IL-4 levels were evaluated by the enzyme-linked immunosorbent assay; and the levels of CD4(+) CD25(+) Foxp3(+) Treg in peripheral blood were measured by flow cytometry. The left knee joints of the model rats appeared palpable swelling and osteophytes, while the body weight, heart and lung function of these rats decreased. The serum IL-4 level was lower, whereas the serum IL-17 level was higher in the model group (P < 0.05). The peripheral blood CD4(+) CD25(+) Foxp3(+) Treg of CD4(+)T cells was significantly lower. Correlation of the changes in the levels of IL-4, IL-17, and Treg suggests that the underlying mechanism may be a reduction of the regulatory effect of Treg. The specific mechanism still requires further study.

T-cell-mediated immune responses are typically low in conditions of malignant glioma which has been known to cause marked immunesuppression and dysregulate major T-cell signaling molecules. Thus, T-cell-based immunotherapies are currently in vogue in the treatment of malignant glioma. The novel glycopeptide, T11TS/S-LFA-3/S-CD58 has previously been shown by our group to be highly efficacious in glioma abrogation in in vivo and in vitro conditions. This glycopeptide ligands to the costimulatory CD2 molecule on T-cells, causing profound immune stimulation leading to glioma abrogation, suggesting probable involvement of T11TS in modulation of the T-cell signaling pathway. The present study offers a multi-targeted approach towards repair of some of the key components of the immunological synapse at the T-cell-APC interface and is therefore the first of its kind to offer a holistic model of restoration of immunological synapse components so as to trigger T-cells towards activation against glioma. The study thus indicates that the totally dysregulated molecular events at the immunological synapse in glioma are restored back to normal levels with the administration of T11TS, which finally culminates in glioma abrogation. The present study thus delineates an important T-cell signaling approach whereby T11TS acts as an anti-neoplastic agent, thus helping to chart out newer avenues in the fight against gliomas.

Full T-cell activation critically depends on the engagement of the TCR (T-cell receptor) in conjunction with a second signal by co-stimulatory receptors that boost the immune response. In the present study we have compared signalling patterns induced by the two co-receptors CD2 and CD28 in human peripheral blood T-cells. These co-receptors were previously suggested to be redundant in function. By a combination of multi-parameter phosphoflow cytometry, phosphokinase arrays and Western blot analyses, we demonstrate that CD2 co-stimulation induces phosphorylation of the TCR-proximal signalling complex, whereas CD28 activates distal signalling molecules, including the transcription factors NF-κB (nuclear factor κB), ATF (activating transcription factor)-2, STAT3/5 (signal transducer and activator of transcription 3/5), p53 and c-Jun. These signalling patterns were conserved in both naïve and effector/memory T-cell subsets. We show that free intracellular Ca(2+) and signalling through the PI3K (phosphoinositide 3-kinase)/Akt pathway are required for proper CD28-induced NF-κB activation. The signalling patterns induced by CD2 and CD28 co-stimulation lead to distinct functional immune responses in T-cell proliferation and cytokine production. In conclusion, CD2 and CD28 co-stimulation induces distinct signalling responses and functional outcomes in T-cells.

Background: Accurate assessment of prognosis remains clinically challenging in stage II to III cutaneous melanoma. Studies have implicated CD2 in immune surveillance, T-cell activation, and antitumor immunity, but its role in melanoma progression warrants further investigation., Objective: We sought to investigate the prognostic role of CD2 in primary cutaneous melanoma., Methods: Patients with American Joint Committee on Cancer stage II and III cutaneous melanoma were identified by retrospective review of dermatopathology databases from 2001 to 2010 at Mount Sinai Medical Center and Geisinger Medical Center. Additional patients were provided by New York University Medical Center based on retrospective review and tissue availability. Immunohistochemistry was performed on tumors from 90 patients with known recurrence status and documented follow-up., Results: Primary tumors from patients who developed recurrent disease had fewer CD2(+) cells (P = .0003). In multivariable analyses including standard clinicopathologic predictors, CD2 was an independent predictor of disease recurrence (P = .008) and overall survival (P = .007). CD2 count correlated with characterization of tumor-infiltrating lymphocytes (P = .0004). Among the intermediate prognosis group of patients with nonbrisk tumor-infiltrating lymphocytes, CD2 count was predictive of disease recurrence (P = .0006) and overall survival (P = .0318)., Limitations: Our retrospective design may have resulted in incomplete representation of patients lacking documented follow-up., Conclusions: CD2 may be an independent predictor of disease recurrence and overall survival among patients with primary cutaneous melanoma., (Copyright © 2014 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Switches from the lymphoid to myeloid lineage during B-cell precursor acute lymphoblastic leukemia (BCP-ALL) treatment are considered rare and thus far have been detected in MLL-rearranged leukemia. Here, we describe a novel BCP-ALL subset, switching BCP-ALL or swALL, which demonstrated monocytosis early during treatment. Despite their monocytic phenotype, 'monocytoids' share immunoreceptor gene rearrangements with leukemic B lymphoblasts. All swALLs demonstrated BCP-ALL with CD2 positivity and no MLL alterations, and the proportion of swALLs cases among BCP-ALLs was unexpectedly high (4%). The upregulation of CEBPα and demethylation of the CEBPA gene were significant in blasts at diagnosis, prior to the time when most of the switching occurs. Intermediate stages between CD14(neg)CD19(pos)CD34(pos) B lymphoblasts and CD14(pos)CD19(neg)CD34(neg) 'monocytoids' were detected, and changes in the expression of PAX5, PU1, M-CSFR, GM-CSFR and other genes accompanied the switch. Alterations in the Ikaros and ERG genes were more frequent in swALL patients; however, both were altered in only a minority of swALLs. Moreover, switching could be recapitulated in vitro and in mouse xenografts. Although children with swALL respond slowly to initial therapy, risk-based ALL therapy appears the treatment of choice for swALL. SwALL shows that transdifferentiating into monocytic lineage is specifically associated with CEBPα changes and CD2 expression.

Lymphocytes play a significant role in the immunological processes of the bovine mammary gland and were found to be the dominant cell population in the milk of healthy udder quarters. The objective of this study was to investigate the quantitative relationship between CD2(+) T and CD21(+) B lymphocytes using flow cytometry. In a first study, quarter foremilk samples from apparently healthy udder quarters [somatic cell counts (SCC) ≤100,000 cells/mL; n=65] were analyzed and compared with diseased quarters (SCC >100,000 cells/mL; n=15). Percentages of CD2(+) T cells were significantly higher in milk samples with SCC ≤100,000 cells/mL than in those with SCC >100,000 cells/mL, whereas percentages of CD21(+) B cells developed in the opposite direction. As a result of this opposing trend, a new variable, the CD2/CD21 index-representing the percentages of CD2(+) cells per CD21(+) cells-was defined. Although diseased quarters with SCC >100,000 cells/mL and the detection of major pathogens revealed generally CD2/CD21 indices <10, values >10 were observed in apparently healthy quarters. Hence, a CD2/CD21 index cutoff value of 10 may be suitable to aid differentiation between unsuspicious and microbiologically suspicious or diseased udder quarters. To test whether CD2/CD21 indices <10 were primarily related to pathogens, quarters with SCC ≤100,000 cells/mL and >100,000 cells/mL with different bacteriological status (culture negative, or minor or major pathogens) were selectively examined in a second biphasic study. In the first trial, 63 udder quarters were analyzed and 55 of these quarters were able to be sampled again in the second trial carried out 14 d later. In both trials, results of the first study were confirmed. Indeed, CD2/CD21 indices <10 were also found in quarters showing SCC ≤100,000 cells/mL and containing minor or major pathogens at the time of the current or previous bacteriological analysis. The results of our examinations indicated a clear relationship between the CD2/CD21 index and the bacteriological status of the mammary gland. In combination with SCC, it offers a new marker for quick differentiation of unsuspicious and microbiologically suspicious or diseased udder quarters., (Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

T11 target structure (T11TS), a membrane glycoprotein has been documented with anti neoplastic activity in glioma bearing animal model in our lab. In this study, we have evaluated the phagocytic potential, expression of VEGF, TNF-α in T11TS treated and untreated macrophages in all four grades of glioma. The data indicates the significant enhancement of phagocytosis in T11TS treated macrophages of grades I and II glioma. There was significant up regulation in TNF-α and significant down regulation in VEGF expression in T11TS treated macrophages in grade I and II glioma. We also attempted to know any possible apoptotic role of T11TS in tumor cells by comparing Bax and Bcl2 in treated and untreated tumor cells of all four grades. We found significant up regulation in Bax expression and down regulation in Bcl2 expression of grades I and II glioma. The outcome may help in pushing this molecule into pharmaceutical domain., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Extensive studies on CD4(+)  CD25(+) regulatory T (Treg) cells suggest that they are important in regulating immune responses. However, mechanisms of peripheral Treg cell homeostasis are unknown. We found that stromal cells isolated from secondary lymphoid organs such as spleen and lymph nodes could support the survival of Treg cells. This was dependent on CD2 engagement and a direct interaction between Treg cells and stromal cells. In the presence of stromal cells, Bim, a pro-apoptotic factor, was partially decreased in Treg cells. This effect could be inhibited by anti-CD2 blocking antibodies, indicating that stimulation through CD2 on Treg cells regulates Bim expression, which may be relevant to Treg cell apoptosis. Therefore, Treg cell interactions with stromal cells through CD2 may be essential for Treg cell survival. Surprisingly, the expression of CD2 ligands on stromal cells was not detected. Hence, it is not clear how CD2 on Treg cells contributes to a direct interaction with the stromal cells and participates in survival support for Treg cells. Taken together, CD2 stimuli were mandatory for Treg cell survival with reduced Bim expression, but CD2 may not function as a direct receptor for molecules on stromal cells., (© 2012 Blackwell Publishing Ltd.)

The low frequency of naturally occurring regulatory T cells (nTregs) in peripheral blood and the suboptimal protocols available for their ex vivo expansion limit the development of clinical trials based on the adoptive transfer of these cells. We have, therefore, generated a simplified, robust and cost-effective platform for the large-scale expansion of nTregs using a gas permeable static culture flask (G-Rex) in compliance with Good Manufacturing Practice. More than 10(9) putative Tregs co-expressing CD25 and CD4 molecules (92 ± 5%) and FoxP3 (69 ± 19%) were obtained within 21 days of culture. Expanded Tregs showed potent regulatory activity in vitro (80 ± 13% inhibition of CD8(+) cell division) and in vivo (suppression or delay of graft-versus-host disease in a xenograft mouse model) indicating that the cost-effective and simplified production of nTregs we propose will facilitate the implementation of clinical trials based on their adoptive transfer.

Porcine γδ T cells have two levels of TCRγδ expression. Whereas TCRγδ(med) cells are mostly CD2(+)CD8(-) and CD2(+)CD8(+), TCRγδ(hi) cells are highly enriched for CD2(-)CD8(-). This distribution is independent of bacterial colonization and it is already established in the thymus prior to export of γδ cells to the periphery. Sorting and cultivation experiments revealed that CD2(-)CD8(-) γδ cells are unable to acquire CD2 and CD8, whereas CD2(+) subsets can gain or loose CD8. There is also differential susceptibility for proliferation between CD2(+) and CD2(-) γδ cells. Although CD2(-)CD8(-) almost do not proliferate, proliferation of CD2(+)CD8(-) and CD2(+)CD8(+) is substantial. Population of CD2(-) γδ cells is also absent in CD1(+) immature thymocytes. Additionally, subpopulations of CD2(+) and CD2(-) γδ cells in the thymus differ in expression of auxiliary surface molecules such as CD25, CD45RA/RC, and MHC class II. Moreover, TCRγδ(hi) cells can generate TCRγδ(med) cells but never the opposite. The only exception is the thymus, where a few TCRγδ(med) cells can be induced to TCRγδ(hi) but only under IL-2 influence. The repertoire of TCRδ is polyclonal in all subsets, indicating that there is the same extent of diversification and equal capability of immune responses. Results collectively indicate that CD2 expression determines two lineages of γδ cells that differ in many aspects. Because CD2(-) γδ cells are missing in the blood of humans and mice but are obvious in other members of γδ-high species such as ruminants and birds, our findings support the idea that circulating CD2(-) γδ T cells are a specific lineage.

Background: We investigated whether graft produced anti-human CD2, mediated by adenovirus (Adv) transduction of pig neonatal islet cell clusters (pNICC), would protect xenografts in a humanized mouse model from immune attack and whether such immunosuppression would remain local., Methods: A mouse anti-human CD2 Ab (CD2hb11) previously generated by us was genetically engineered to produce chimeric and humanized versions. The three forms of CD2hb11 were named dilimomab (mouse), diliximab (chimeric) and dilizumab (humanized). All 3 forms of CD2hb11 Ab were tested for their ability to bind CD3(+) human T cells and to inhibit a human anti-pig xenogeneic mixed lymphocyte reaction (MLR). They were administered systemically in a humanized mouse model in order to test their ability to deplete human CD3(+) T cells and whether they induced a cytokine storm. An adenoviral vector expressing diliximab was generated for transduction of pNICC. Humanized mice were transplanted with either control-transduced pNICC or diliximab-transduced pNICC and human T cells within grafts and spleens were enumerated by flow cytometry., Results: Dilimomab and diliximab inhibited a human anti-pig xenogeneic response but dilizumab did not. All 3 forms of CD2hb11 Ab bound human T cells in vitro though dilimomab and diliximab exhibited 300-fold higher avidity than dilizumab. All 3 anti-CD2 Abs could deplete human CD3(+) T cells in vivo in a humanized mouse model without inducing upregulation of activation markers or significant release of cytokines. Humanized mice transplanted with diliximab-transduced pNICC afforded depletion of CD3(+) T cells at the graft site leaving the peripheral immune system intact., Conclusions: Local production of a single Ab against T cells can reduce graft infiltration at the xenograft site and may reduce the need for conventional, systemic immunosuppression., (© 2013 John Wiley & Sons A/S.)

Neonates are highly susceptible to infectious diseases and defective antiviral pDC immune responses have been proposed to contribute to this phenomenon. Isolated cord blood pDCs innately responded to a variety of TLR7 and TLR9 dependent viruses, including influenza A virus (IAV), human immunodeficiency virus (HIV) or herpes-simplex virus (HSV) by efficiently producing IFN-α, TNF-α as well as chemokines. Interestingly, following activation by CpGA, but not viruses, cord pDCs tend to survive less efficiently. We found that a hallmark of pDCs in neonates is an extended CD2+pDCs compartment compared to adult pDCs without affecting the antiviral IFN-α response. Within CD2+pDCs, we identified a subpopulation expressing CD5 and responsible for IL-12p40 production, however this population is significantly decreased in cord blood compared to adult blood. Therefore, neonatal pDCs clearly display variation in phenotype and subset composition, but without major consequences for their antiviral responses.

Introduction: Aberrant expression of T-cell markers is occasionally observed in B-cell lymphomas. We conducted a retrospective study to establish its incidence and to determine its relationship with clinical features of patients with diffuse large B-cell lymphoma (DLBCL)., Patients and Methods: We reviewed DLBCL patients diagnosed between January 2002 and April 2009. Patients fulfilled the following criteria: (1) age >18 years, (2) HIV negative, (3) B-cell lymphoma confirmed by restricted expression of surface immunoglobulin light chains by flow cytometry (FCM). Aberrant T-cell marker expression (ATCME) was defined as positivity for CD2, CD3, CD4, CD7, and/or CD8 on DLBCL cells by FCM. Phenotyping was also performed by immunohistochemistry (IHC). Patients were grouped according to positive or negative ATCME and their clinical features including survival were compared., Results: Of 150 patients, 11 (7.3%) showed ATCME; CD2 and CD7 were most often expressed. ATCME was less often detected and the signal was weaker using IHC. There were no statistically significant differences in clinical features between the two groups., Conclusions: FCM may be useful to detect ATCME in a small amount of lymphoma cells. The mechanism responsible for ATCME, and whether it contributes in any way to the pathogenesis of B-cell neoplastic transformation, requires clarification., (Copyright © 2013 S. Karger AG, Basel.)

T cells bearing chimeric antigen receptors (CARs) are broadly categorised into first- and second-generation receptors. Second-generation CARs contain a co-stimulatory signalling molecule and have been shown to secrete IL-2, undergo greater proliferation and to have enhanced persistence in vivo. However, we have shown that T cells bearing a first-generation CAR containing a CD19-targeting scFv (single-chain variable fragment) and the CD3ζ-signalling domain are able to produce IL-2 upon co-culture with CD19(+) B-cell lymphomas independent of CD28 activity. Here, we report that signalling through endogenous CD2 following ligation with its ligands, CD48 in mouse and CD58 in humans, drives IL-2 production by first-generation CD19-specific CAR. Moreover, the high levels of IL-2 produced by human T cells engrafted with a second-generation CD28-containing CAR during target-cell recognition are dependent to a degree upon CD2 receptor activity. These observations highlight the fact that the functional activity induced by T-cell-expressed CARs is dependent upon endogenous 'natural' receptor interactions. A deeper understanding of the role of these activities will serve to further refine the design of future CARs to either exploit or avoid these interactions.

The Fc receptor on NK cells, FcγRIIIA (CD16), has been extensively studied for its role in mediating antibody-dependent cellular cytotoxicity (ADCC). A homozygous missense mutation in CD16 (encoding a L66H substitution) is associated with severe herpesvirus infections in rare patients. Here, we identified a new patient with this CD16 mutation and compared the patient's NK cells to those of the originally reported patient. Patients with the L66H mutation had intact ADCC, but deficient spontaneous NK cell cytotoxicity and decreased surface expression of CD2, a coactivation receptor. Mechanistic studies in a human NK cell line, NK-92, demonstrated that CD16 expression correlated with CD2 surface levels and enabled killing of a melanoma cell line typically resistant to CD16-deficient NK-92 cells. An association between CD16 and CD2 was identified biochemically and at the immunological synapse, which elicited CD16 signaling after CD2 engagement. Stable expression of CD16 L66H in NK-92 cells recapitulated the patient phenotype, abrogating association of CD16 with CD2 as well as CD16 signaling after CD2 ligation. Thus, CD16 serves a role in NK cell-mediated spontaneous cytotoxicity through a specific association with CD2 and represents a potential mechanism underlying a human congenital immunodeficiency.

We have evaluated the effect of combining CD2 with conventional antimonial (sb) therapy in protection in BALB/c mice infected with either drug sensitive or resistant strain of Leishmania donovani with 3×10(7) parasites via-intra-cardiac route. Mice were treated with anti CD2 adjunct SAG sub-cutaneously twice a week for 4 weeks. Assessment for measurement of weight, spleen size, anti-Leishmania antibody titer, T cell and anti-leishmanial macrophage function was carried out day 0, 10, 22 and 34 post treatments. The combination therapy was shown boosting significant proportion of T cells to express CD25 compared to SAG monotherapy. Although, the level of IFN-γ was not statistically different between combination vs monotherapy (p=0.298) but CD2 treatment even alone significantly influenced IFN-γ production than either SAG treatment (p=0.045) or with CD2 adjunct SAG treatment (p=0.005) in Ld-S strain as well as in Ld-R strain. The influence of CD2 adjunct treatment was also documented in anti-leishmanial functions in macrophages. As shown, the super-oxide generation began enhancing very early on day 10 after SAG treatment with CD2 during which SAG action was at minimum. Interestingly, the super-oxide generation ability remained intact in macrophage after treatment with immuno-chemotherapy even in mice infected with Leishmania resistant strain. Unlike SAG treatment, treatment of SAG with CD2 also led to production of nitric oxide and TNF-α, resulting in resulting in most effective clearance of L. donovani from infected macrophages. Our results indicate that CD2, which can boost up a protective Th1 response, might also be beneficial to enable SAG to induce Macrophages to produce Leishmanicidal molecules and hence control the infection in clinical situation like Kala-azar. Drug resistance is the major impedance for disease control but the encouraging results obtained after infecting mice with resistant strain of the parasite strongly imply that this drug can be effective even in treating resistant cases of Kala-azar., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The estimated prevalence of extranodal non-Hodgkin lymphoma ranges from 10 to 35% of all cases; a finding in the larynx is extremely rare. We describe the case of a 77-year-old man who presented for evaluation of a 1-month history of minor swallowing difficulty, cough, and a foreign-body sensation in the throat. Fiberoptic endoscopy detected a tumor mass on the left aryepiglottic fold. Vocal fold mobility was normal. A biopsy specimen was obtained, and microscopic analysis revealed that the stratified squamous epithelium was partially eroded by abundant infiltrate that had occupied the entire submucosa. The submucosal infiltration consisted of lymphatic cells, including small, medium-sized, and large cells with an anaplastic appearance. On immunohistochemical analysis, the lymphoma cell population stained positive for CD3 and CD2, focally positive for CD56, and negative for CD4, CD5, and CD7. In addition, tumor cells expressed TIA-1, perforin, and granzyme B. A complete radiologic, pulmonologic, and hematologic workup found no other tumor. The patient underwent two cycles of chemotherapy followed by radiotherapy, and he experienced complete tumor regression. At the 1-year follow-up, findings on fiberoptic endoscopy of the larynx were normal, and positron-emission tomography found no evidence of a recurrence. The prognosis for this type of tumor is good when the diagnosis is made in the early phase of the disease. Long-term follow-up is advisable for the timely detection of possible local or distant recurrences, which are common.

Earlier studies investigating the cross-reactivity of antibodies submitted to the HLDA8 had used flow cytometry as a method of choice to screen mAbs for reactivity with equine leukocytes, including two-color flow-cytometry to characterize the lymphocyte population they detect. In addition, immuno-histochemistry (IHC) was used to detect distribution of positive cells in lymphoid tissue sections. In this study we performed immunoprecipitation (IP) to complement the previous results and add valuable information regarding the molecules detected by the cross-reacting antibodies. Surface molecules from primary equine PBMC or the equine cell line T8888 were biotinylated prior to precipitation to determine the molecular weight of the corresponding molecules in a western blot using streptavidin-AP. 21 out of 24 mAbs precipitated the molecules with a MW corresponding to its human orthologue. Positive mAbs were directed against CD2, CD5, CD11a, CD11b, CD14, CD18, CD21, CD44, CD83, CD91, CD172a, MHCI and MHCII. Three mAbs directed against CD49d, CD163, and CD206 which were unambiguously identified earlier by flow cytometry failed to immunoprecipitate the corresponding CD molecule. MAbs detecting CD molecules which are expressed internally like CD68 and mAbs of IgM class could not be included into this approach., (Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.)

Membrane nanotubes are thin membranous projections that physically connect two cells. While nanotubes have been studied in human natural killer (NK) cells and are implicated in aiding NK cell cytotoxic function, requirements for their formation to susceptible target cells remain incompletely understood. Here we demonstrate that the CD2-CD58/48 receptor-ligand interaction promotes and is required for nanotube formation in human NK cells. In the CD2(-) NK cell line YTS, a stable CD2 expression variant enabled effective nanotube formation, and was associated with better cytotoxic function. Importantly, only interactions between an NK cell and a susceptible target cell were associated with multiple nanotubes and the number of nanotubes was inversely correlated with their length. Quantitative live cell fluorescence microscopy of CD2 nanotubes revealed time-dependent enrichment and localization of CD2 to the nanotube tip, and blocking CD2 receptor-ligand interactions prevented nanotube formation. Increased nanotube formation was not simply a feature of receptor-ligand pairing, as a KIR-MHC interaction in the same cell line system failed to promote nanotube formation. Additionally, blocking LFA-1-ICAM and 2B4-CD48 receptor-ligand interactions failed to inhibit nanotube formation. Thus only specific receptor-ligand pairs promote nanotubes. CD2 also promoted nanotube formation in ex vivo NK cells suggesting that CD2 plays a crucial role in the generation of nanotubes between an NK cell and its target.

Background: According to the World Health Organization (WHO) classification the diagnosis of systemic mastocytosis (SM) relies on bone marrow (BM) examination and is based on one major and four minor criteria. Herein, we used WHO criteria to compare flow cytometry (FC) with other available techniques in the diagnosis of SM after BM examination., Methods: We analyzed a cohort of 95 patients with suspect SM. All patients underwent comprehensive BM examination by using cytology, immunohistochemistry, FC and molecular study for mutation of c-Kit and serum tryptase dosage. FC evaluation was based on a combination of monoclonal antibodies, specifically CD25/CD2/CD45/CD34/CD117., Results: Seventy-four out of ninety-five patients were diagnosed with indolent SM (n = 59) or monoclonal mast cell activation syndrome (n = 15) because satisfying less than 3 minor criteria. Thirty-nine out of these seventy-four patients fulfilled the major histological criterion, whereas the presence of a minor criterion was assessed by FC, molecular study, cytology, and tryptase level in 70/74, 52/67, 56/74, and 42/74 patients, respectively. FC showed higher sensitivity than IHC in detection of CD25+ mast cells (MC) (92.9% vs. 73.8%; P = 0.019), especially in the absence of the major histological criterion (90.5% vs. 47.6%; P = 0.003). Moreover, CD2 expression was documented by FC and IHC in 97.1% and 35.3% of cases, respectively (P < 0.001)., Conclusions: FC showed the best sensitivity for identifying abnormal MC compared to other techniques, especially in cases with low MC burden. Therefore, we hope for a major role of FC in the diagnostic work-up of clonal MC disorders., (2011 International Clinical Cytometry Society.)

Immunosuppression is an important treatment modality in transplantation and human diseases that are associated with aberrant T cell activation. There are considerable differences regarding the cellular processes targeted by the immunosuppressive drugs that are in clinical use. Drugs like azathioprine (Aza) mainly act by halting proliferation of fast dividing cells, whereas others like cyclosporine A (CsA) specifically target signaling pathways in T cells. Since the outcome of T cell responses critically depends on the quality and strength of costimulatory signals, this study has addressed the interplay between costimulation and the immunosuppressive agents CsA and Aza during the in vitro activation of human T cells. We used an experimental system that allows analyzing T cells activated in the presence of selected costimulatory ligands to study T cells stimulated via CD28, CD2, LFA-1, ICOS or 4-1BB. The mean inhibitory concentrations (IC(50)) for Aza and CsA were determined for the proliferation of T cells receiving different costimulatory signals as well as for T cells activated in the absence of costimulation. CD28 signals but not costimulation via CD2, 4-1BB, ICOS or LFA-1 greatly increased the IC(50) for CsA. By contrast, the inhibitory effects of Aza were not influenced by T cell costimulatory signals. Our results might have implications for combining standard immunosuppressive drugs with CTLA-4Ig fusion proteins, which act by blocking CD28 costimulation., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The human CD2 (hCD2) locus control region (LCR) inserted in the mouse CD8 gene complex activates expression of the CD8 genes in T cell subsets in which the CD8 locus is normally silenced (e.g., CD4(+) single-positive T cells). In this article, we show that, in conditional mCD8/hCD2-LCR (CD8/LCR) knock-in mice, the continuous presence of the hCD2-LCR is required for this effect. Deletion of the inserted hCD2-LCR in a developmental stage and cell lineage-specific manner revealed that the temporary presence of the LCR during early development does not permanently alter the expression pattern of the CD8 genes. As a result, cells that have been affected by the insertion of the LCR can convert to their destined phenotype once the LCR is removed. DNaseI hypersensitive sites 1 and 2 of the hCD2-LCR influence the expression of the CD8 genes in a similar manner as does the full LCR, whereas insertion of hypersensitive site 3 alone of the LCR does not result in a changed expression pattern. This analysis revealed a dynamic interaction between the hCD2-LCR and the endogenous regulatory elements of the CD8 genes.

Objective: To determine peripheral frequencies of CD4+CD25highFoxp3+ regulatory T cells (Treg) in prostate cancer (PCa) patients, and to investigate if there is a correlation between peripheral Treg and total serum prostate specific antigen (PSA) levels in PCa patients., Methods: Peripheral blood mononuclear cells from 56 subjects undergoing diagnostic prostate biopsies PSA>/=2.5 ng/ml were analyzed for Treg numbers. Association between the peripheral Treg and serum PSA values was first determined in the entire population, including people with no prostate pathology, PCa, and benign prostate hyperplasia (BPH) patients, and second, in 9 PCa patients before and after curative prostatectomy. In this study, the 3 groups were compared. This project was performed in the Akdeniz University Immunology laboratory, and the Urology outpatient clinic, Antalya, Turkey from December 2008 to January 2010., Results: Peripheral Treg frequencies were significantly increased in the PCa patients (n=19, 3.23+/-1.59) compared with BPH patients (n=27, 1.66+/-0.80), and healthy subjects (n=10, 1.08+/-0.43) (p=0.007). The percentage of Treg in BPH patients was also significantly higher than healthy subjects (p=0.007). The increase of Treg in BPH and PCa patients was positively correlated with total serum PSA levels (r=0.75; p=0.007)., Conclusion: Peripheral Treg densities are correlated with PSA in BPH and PCa patients, suggesting that PSA may have a role in Treg induction and/or maintenance.