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Summary: The immune system is composed of a variety of different T-cell lineages distributed through both secondary lymphoid tissue and non-lymphoid tissue. The intestinal epithelium is a critical barrier surface that contains numerous intraepithelial lymphocytes that aid in maintaining homeostasis at that barrier. This review focuses on T-cell receptor αβ (TCRαβ) CD8αα intraepithelial lymphocytes, and how recent advances in the field clarify how this unique T-cell subset is selected, matures, and functions in the intestines. We consider how the available evidence reveals a story of ontogeny starting from agonist selection of T cells in the thymus and finishing through the specific signaling environment of the intestinal epithelium. We conclude with how this story raises further key questions about the development of different ontogenic waves of TCRαβ CD8αα IEL and their importance for intestinal epithelial homeostasis. The intestine is home to a variety of T-cell subsets. One particular T-cell subset, TCRαβ CD8αα intraepithelial lymphocytes (IELs), is selected in the thymus. This review discusses the factors and events that regulate the selection of TCRαβ CD8αα IELs. [ABSTRACT FROM AUTHOR]

Clostridium perfringens epsilon toxin (ETX) is the third most lethal bacterial toxin and has been suggested to be an environmental trigger of multiple sclerosis, an immune-mediated disease of the human central nervous system. However, ETX cytotoxicity on primary human cells has not been investigated. In this article, we demonstrate that ETX preferentially binds to and kills human lymphocytes expressing increased levels of the myelin and lymphocyte protein MAL. Using flow cytometry, ETX binding was determined to be time and dose dependent and was highest for CD4+ cells, followed by CD8+ and then CD19+ cells. Similar results were seen with ETX-induced cytotoxicity. To determine if ETX preference for CD4+ cells was related to MAL expression, MAL gene expression was determined by RT-qPCR. CD4+ cells had the highest amount of Mal gene expression followed by CD8+ and CD19+ cells. These data indicate that primary human cells are susceptible to ETX and support the hypothesis that MAL is a main receptor for ETX. Interestingly, ETX bindings to human lymphocytes suggest that ETX may influence immune response in multiple sclerosis. [ABSTRACT FROM AUTHOR]

In our previous papers, we have shown that human T cells produce a unique eosinophil chemotactic factor (ECF), termed Ecalectin, with a molecular weight of about 30–50 kD during interaction with BALL-1 (a B cell line) extracts, antigen or mitogen. A 1.6-kB cDNA was isolated from a human T cell-derived expression library that encodes Ecalectin. Ecalectin is a 36-kD protein consisting of 323 amino acids based on its deduced amino acid sequence. Ecalectin was found to be a variant of human galectin-9, a member of the growing family of animal lectins exhibiting affinity for β-galactosides. Recombinant Ecalectin, expressed in COS cells, exhibited potent ECF activity in vitro and in vivo in a dose-dependent manner but not chemotactic activity for neutrophils, lymphocytes, or monocytes. The finding that the Ecalectin transcript is present in various lymphatic tissues and that its expression increases substantially in antigen-activated peripheral blood mononuclear cells suggests that Ecalectin is an important T cell-derived regulator of eosinophil recruitment in allergic reaction sites. [ABSTRACT FROM AUTHOR]

This article presents abstracts for various research papers to be presented in the European Society for Dermatological Research's symposium on September 26-28, 1997. These research papers pertain to subjects like the eortic classification for primary cutaneous lymphomas, different prognosis between cutaneous and systemic lymphoproliferative disorders, parapsoriasis and early cutaneous T cell lymphoma, immunoglobulin gene rearrangement of pseudo B-cell lymphomas and prognostic significance of polymerase chain reaction detectable dominant T lymphocyte clones.

Lactoferrin (Lf), an iron-binding protein in milk, mucosal secretions and neutrophil granules has bactericidal properties and is a source of iron for breast-fed infants. In this paper the authors show that most in vivo activated lymphocytes, i.e. freshly isolated lymphocytes from first trimester human decidua, and most in vitro activated human blood lymphocytes, express lactoferrin receptors (Lf-R), while unstimulated blood lymphocytes do not. All major lymphocyte subsets, i.e. αβ T cells, γδ T cells, CD8+ T cells, CD4+ T cells, B cells and NK cells, express Lf-R after activation. The proportion of Lf-R expressing activated γδ T cells is significantly larger than that of activated αβ T cells. Lf-R and transferrin receptors (Tr-R/CD71) show the same kinetics of appearance on activated blood lymphocytes and are, to a large extent, expressed on the same cells. However, 35% of decidual lymphocytes and 15% of activated blood lymphocytes express Lf-R only. Addition of Lf to cultures containing an optimal concentration of Tr augments the proliferative response to polyclonal T cell activators and alloantigens, suggesting that presently used standard culture conditions for in vitro activation are suboptimal in particular for γδ T cells. Lf-R on decidual lymphocytes contain bound Lf, which probably is produced locally. The results suggest that Lf is a growth-supporting factor, especially important in local immune responses in the mucosa. [ABSTRACT FROM AUTHOR]

Background Comparable T cell-containing and T cell-depleted culture systems for human IgE synthesis arc currently not available. Objective This has prompted us to develop peripheral blood mononuclear cell (PBMC) based culture systems for human IgE synthesis in the presence and absence of T cells. Methods In this paper we describe simplified conditions for in vitro synthesis of high levels of IgE by human peripheral blood B cells, both in T cell-containing cultures and in anti-CD40 stimulated T cell-depleted cultures. Results T cell-depleted cultures released approximately 20 times more IgE [range 4I0-2220ng/mL (mean 1270 ng/mL); based on six experiments using cells from three donors] than did T cell-containing cultures [range 23-105 ng/mL (mean 58ng/mL); based on 15 experiments using cells from three donors]. Reconstitution experiments were performed lo investigate the role of T cells on IgE synthesis. Adding T cells back to the anti-CD40 stimulated T cell-depleted cultures resulted in a dose-dependent inhibition of IgE production. In the absence of anti-CIMO low numbers of T cells stimulated, while high numbers suppressed, IgE production: the optimal ratio of T cells to non-T cells for maximal IgE production was found to be 1:1. At this ratio, irradiated (non-replicating) T cells supported a much greater IgE synthesis than did non-irradiated T cells. Conclusion The development of these systems provides directly comparable T cell-containing and T cell-depleted cultures for human IgE synthesis from peripheral blood, allowing further study of the role of T cells in IgE regulation. These systems will also be of use for determining whether potential modulators of IgE synthesis act on the T cells or on other cell types. [ABSTRACT FROM AUTHOR]

Background Selected cytokines produced by allergen specific CD4+ T cells from atopic individuals contribute to both the specific and non-specific effector mechanisms of the allergic immune response. The chemokine family of cytokines and tumour necrosis factor (TNF)-α are leucocyte regulatory and proinflammatory molecules. The chemokines include interleukin (IL)-8 and the RANTES/SIS cytokines. Objective There bas been no systematic survey of chemokine production in T-cell subtypes. Because of their wide range of biological properties, it might be expected that they would be closely regulated by T cells. This paper illustrates one way (through the characterization of T-cell clones) these questions might be addressed. Methods Northern blot analysis was used to quantitate steady state transcription of selected cytokine genes and enzyme linked immunosorbent assay (ELISA) was used to quantitate soluble product. Results mRNA expression of the chemokines (IL-8. HuMIP-lα and HuMIP-lβ) and TNFα is upregulated in TH2-like cloned house dust mite reactive human CD4+ T cells under conditions of activation and during the induction phase of anergy. Although the development of anergy superinduces mRNA for both IL-8 and TNFα, protein production is low compared with that released during activation. In contrast, RANTES, a chemoattractant for CD4+ /CD45RO+ memory T cells, eosinophils and basophils, is constitutively expressed at the RNA level by the T cells and not modulated by signals of activation and anergy induction. The production of IL-2, IL-4 and IL-5 mRNA and proteins during the induction of anergy peaks at 2h after stimulation, whereas the kinetics following activation of the T cells is delayed in comparison. Conclusion These data show that the induction of the anergic state coincides with post-transcriptional regulation of selected cytokine genes. Further study of these phenomena will impact on our understanding of the mechanisms of induction of anergy and the regulation of allergic immune responses in desensitization. [ABSTRACT FROM AUTHOR]

IL-6, an important mediator of the acute phase response, has been implicated in the pathogenesis of rheumatoid arthritis (RA). Many cell types including macrophages, T cells. H cells, endothelial cells and fibroblasts can produce this cytokine and production is largely regulated at the level of gene transcription or mRNA stabilization. In this paper we have first measured the levels of IL-6 activity in synovial fluid (SF) and serum from patients with RA and then localized IL-6-producing cells in the synovium by in situ hybridization combined with immunophenotyping. Patients with RA had raised levels of IL-6 in both SF and serum compared with patients with osteoarthritis and age-matched healthy controls. in individual RA patients tested serially after admission to hospital, serum IL6 was initially raised and, unexpectedly. increased with clinical improvement, in situ hybridization of IL-6 mRNA showed positive cells both in the lymphocyte-rich aggregates and adjacent to small blood vessels. With immunophenotyping it was found that cells containing IL-6 mRNA were often in contact with CD 14+ tissue macrophages and double immunophenotyping revealed that immuno- reactive IL-6 was often associated with synovial T cells. [ABSTRACT FROM AUTHOR]

This paper describes the spontaneous occurrence of an autoimmune uveoretinitis in nude (nu/nu) mice reconstituted when 4 weeks old by the grafting of rat embryonic thymus. The uveoretinitis was characterized histologically by progressive loss of the photoreceptor layer, observed in 4.0, 17.6, 42.9% and 71.4% of such mice at 3, 5, 7 and 12 months of age, respectively. Mice with uveoretinitis were shown to have serum IgG antibody reactive by indirect immunofluorescence with retinal photoreceptors, and with interphotoreceptor retinoid-binding protein (IRBP), but not retinal S-antigen, by immunoblotting and ELISA. A uveoretinitis could be adoptively transferred to syngeneic ungrafted nude mice by splenic CD4+ T cells from diseased animals. This is the first experimental model of a (T cell mediated) autoimmune uveoretinitis which develops spontaneously and which is not dependent upon deliberate sensitization with retinal antigens and adjuvants. [ABSTRACT FROM AUTHOR]

The binding of EPF to lymphocytes stimulates the release of soluble mediators, active in T cell dependent reactions, namely the rosette inhibition test and the adoptive transfer of contact sensitivity. On the basis of their ability to inhibit the delayed type hypersensitivity reaction in this latter assay, they have been classified as suppressor factors. This paper describes the identification of two EPF-induced suppressor factors. Unlike EPF which is neither species-restricted nor strain-restricted, these factors are genetically restricted in their action in the rosette inhibition test EPF-S1 (estimated Mr 14,000) is restricted to the I region of the mouse MHC, while EPF-S2 (estimated Mr 55,000) is restricted to a locus (or loci) outside the MHC. Like other antigen non-specific factors, release of these suppressor factors can be stimulated also by Con A. [ABSTRACT FROM AUTHOR]

Freshly isolated B cells from chronic lymphocytic leukaemia patients (B-CLL) have been previously shown to induce a strong proliferative response and high levels of NK-like activity in lymphocytes from healthy donors. The present paper deals with the origin, mitotic state, target spectrum and cell surface phenotype of the NK-like effectors generated after stimulation with B-CLL. Experiments using large granular lymphocytes (LGL) and T cells as responders demonstrated that most of the precursors of the newly generated NK-like effectors express the CD3 antigen. The induction of NK-like activity paralleled cell activation, as judged by blast transformation, thymidine uptake and appearance of cell surface activation markers. The newly generated NK-like effectors displayed a T cell phenotype and a broader target repertoire than native NK cells. [ABSTRACT FROM AUTHOR]

The antigen-induced DNA synthesis in vitro in lymphocytes from patients with acute Plasmodium falciparum malaria was investigated. The patients and healthy controls from Sweden or Colombia were the same as those studied in the accompanying paper (Troye-Blomberg el al., 1983). The malarial antigens used were sonicated membrane preparations or purified and concentrated supernatants from in vitro cultures of P. facliparum, similar preparations derived from normal human erythrocytes served as control antigen. In the patients' lymphocytes P. falciparum antigens induced a weak or moderate but significant stimulation of DNA synthesis, peaking after 3-4 days of incubation. This early response was specific for P. faleiparum since it was not obtained with lymphocytes from healthy donors nor with those from patients with acute P. vivax or P. ovale malaria. No antigen-induced response was seen in about half of the P.falciparum patients. However in a few negative eases, available for consecutive testing, positive reactions were seen with lymphocytes taken 2 weeks after infection when the blood of these patients was free of parasites. The early response induced in patients' lymphocytes to the P. falciparum antigens was not obtained with RBC antigen, however, these preparations frequently induced a response rising to significant levels later during incubation (day 5-6)- Similar delayed responses were obtained when either- patients' or control donors' lymphocytes were exposed to the P. falciparum antigens. This indicates that both the RBC and the parasite preparations contained mitogenic substances affecting human lymphocytes in general and easily obscuring the P, falciparum specific responses seen only in the patients. This latter response was relatively low and short lived, suggesting that it reflected a secondary in vitro stimulation of in vivo primed lymphocytes and that it was regulated by suppressor mechanisms. [ABSTRACT FROM AUTHOR]

Peripheral lung tissue contains large numbers of T cells, strategically located for immune surveillance at the blood-air interface. Given the intensity of antigenic exposure at this site, it is clear that local T-cell activation events require strict control, in order to maintain tissue homeostasis. How this control is achieved in this unique tissue microenvironment is unknown, and the present study sought to elucidate the process via detailed analysis of the surface phenotypic characteristics of freshly isolated lung T cells. We report below that these cells display typical characteristic of ‘postactivation’, notably elevated basal Ca2+ concentrations, down-modulated T-cell receptors, expression of Ia and ‘late’ activation antigens and concomitant CD4/CD8. However, levels of interleukin-2 receptor and CD2 expression were below those expected of ‘activated’ T-cell populations, and virtually all of the cells were found to be in the G0/G1 phases of the cell cycle. These properties bear a remarkable similarity to those of T cells activated in the presence of endogenous tissue (alveolar) macrophages from the lung (see accompanying paper). We hypothesize that they reflect the in vivo operation of an endogenous macrophage-mediated T-cell anergy-induction process, the function of which is to limit the local clonal expansion of T cells in peripheral lung tissue after in situ activation. [ABSTRACT FROM AUTHOR]

Alveolar macrophages (AM) are recognized as archetypal ‘activated’ macrophages with respect to their capacity to suppress T-cell responses to antigen or mitogen, and this function has been ascribed an important role in the maintenance of local immunological homeostasis at the delicate blood: air interface. The present study demonstrates that this suppression involves a unique form of T-cell anergy, in which ‘AM-suppressed’ T cells proceed normally through virtually all phases of the activation sequence including Ca2+ flux, T-cell receptor (TCR) modulation, cytokine [including interleukin-2 (IL-2)] secretion and IL-2 receptor (IL-2R) expression. However, the ‘suppressed’ T cells fail to up-regulate CD2, and do not re-express normal levels of TCR-associated molecules after initial down-modulation; moreover, they are unable to transduce IL-2 signals leading to phosphorylation of IL-2R-associated proteins, and remained locked in G0/G1. The induction of this form of anergy is blocked by an NO-synthase inhibitor, and is reversible upon removal of AM from the T cells, which then proliferate in the absence of further stimulation. We hypothesize that this mechanism provides the means to limit the magnitude of local immune responses in this fragile tissue microenvironment, while preserving the capacity for generation of immunological memory against locally encountered antigens via clonal expansion of activated T cells after their subsequent migration to regional lymphoid organs. In an accompanying paper, we demonstrate that a significant proportion of T cells freshly isolated from lung exhibit a comparable surface phenotype. [ABSTRACT FROM AUTHOR]

A receptor which binds secretory lgA (sIgA) is expressed on human T cells from patients with systemic lupus erythematosus, rheumatoid arthritis, Behcet's syndrome and IgA nephropathy and on normal T cells following phytohaemagglutinin (PHA) stimulation. The specificity of this receptor was initially probed with a panel of normal serum immunoglobulins in competitive inhibition assays with sIgA using two-colour immunofluorescence. While the receptor showed the strongest affinity for igAl (IC5010-6 M), IgD which has a similarly glycosylated hinge region to IgAl, also bound to the receptor (IC50 10-5 M). IgA2, which lacks the 'O'-glycosylated hinge region, did not significantly inhibit the binding at these concentrations suggesting that the IgA determinants for this receptor might be the oligosaccharides present in the hinge region of IgAl. IgAl has up to 10 'O'-linked oligosaccharides and four N-linked oligosaccharides per molecule. In order to probe the role of the 'O'-linked hinge sugars in the binding event, a sugar library was prepared from IgAl by a procedure designed to release 'O'-linked oligosaccharides preferentially, and to retain them in the natural closed ring formation. The sugars were released by hydrazinolysis at 65° and the resulting oligosaccharide library analysed by high voltage paper electrophoresis (HVE) and P4 gel permeation chromatography. Competitive inhibition studies demonstrated that both the library and the individual 'O'-linked sugars associated with IgA1 were implicated in the binding of IgAl to this receptor (IC50 between 1 × 10-5 M and 6 × 10-s M). Within this range the individual sugars showed small differences in their affinity for the receptor in the following order: Galβ3GalNAc = NeuNAc2α3(6)Galβ3GalNAc > NeuNAc2α3(6)Galβ3[NeuNAc2α6]GalNAc ≥ GalNAc. [ABSTRACT FROM AUTHOR]

Mitogen-transformed human peripheral blood lymphocytes and tonsil blasts were examined by rosette formation to detect the presence of membrane-bound immunoglobulin (Ig) and surface receptors for fixed IgG and fixed C3. In addition, the capacity of these cells to rosette with sheep erythrocytes was evaluated as a reaction characteristic of T lymphocytes. In order for clear morphological recognition of the rosetting transformed lymphocytes and the rosetting tonsil blasts a cytocentrifuge technique was developed and used in conjunction with autoradiography and/or with Romanowsky stains. Using these techniques and the culture methods described in this paper phytohaemagglutinin, pokeweed mitogen, streptococcal filtrates and purified protein derivative stimulated predominantly T cells in the peripheral blood of man. A minority of the transformed cells in these mitogen-stimulated cultures (<24%) did rosette with B lymphocyte markers and presumably represent a B-cell response. No significant differences were found between the T- or B-cell specificity of the mitogens investigated. Lymphoid preparations from tonsils excised from normal donors with recurrent tonsillitis were found to contain 6-15% lymphoblasts and the iarge majority of these cells formed rosettes with the B-cell markers, less than 20% of these lymphoblasts formed spontaneous sheep erythrocyte rosettes. Using a mixed rosetting technique a small proportion (<5%) of PHA-transformed cells and tonsil lymphoblasts were found to have combined sheep Fc or combined sheep C3 receptors. The investigation of B- and T-lymphocyte surface markers on mitogentransformed lymphocytes was extended to neopiastic lymphocyte populations and it was found that the majority of transformed cells (>70%) present in chronic lymphocytic leukaemia cultures stimulated with PHA after 6 days incubation were transformed T lymphocytes. [ABSTRACT FROM AUTHOR]

Previous reports have shown abnormal responses mediated via the TCR/CD3 pathway in T lymphocytes from systemic lupus erythematosus (SLE) patients. Recently, we and others have reported augmented TCR/CD3-mediated responses in lupus T cells. It is possible that the pattern of downstream biochemical signals triggered by TCR/CD3 ligation may be altered in T lymphocytes from patients with SLE, thus leading to abnormal distal cell responses. In this paper we have examined the phosphorylation of proteins on tyrosine residues in peripheral blood T lymphocytes from a group of SLE patients and controls. We found a lower frequency of constitutively tyrosine-phosphorylated 119- and 113-kDa substrates and an enhanced frequency of tyrosine-phosphorylated 66- and 25-kDa proteins in unstimulated cultures of SLE T lymphocytes, suggesting an altered pattern of tyrosine phosphorylation in T cells from patients in vivo. Additionally, the protein tyrosine phosphatase (PTP) activity of CD45 immunoprecipitates was lower in unstimulated lupus T cells and was enhanced after stimulation via the CD3 pathway in lupus but not control T lymphocytes. The present results seem to suggest abnormal regulation of in-vivo tyrosine phosphorylation in T cells from patients with SLE. [ABSTRACT FROM AUTHOR]

In a previous work the authors demonstrated that immunization with Schistosoma mansoni 28-kDa glutathion-S-transferase (Sm28GST) was able to reduce hepatic damage in infected mice and that the adoptive transfer of Sm28GST-specific T cells reproduced the protective effect obtained with the recombinant molecule. In the present paper, the authors show that Sm28GST is also able to stimulate an antigen-specific, cytotoxic T-cell response against Sm28GST-pulsed P815 target cells in normal mice and that effector cells induced in vivo were classical Class I MHC-restricted CD8+ lymphocytes. The authors found no spontaneous CTL activity against Sm28GST-pulsed target cells during the course of the infection by S. mansoni although Sm28GST is expressed at different developmental stages of the parasite. It was observed, however, that immunization with Sm28GST is sufficient to elicit a significant level of CTL response for 6 weeks in infected mice. The role of these Class I MHC-restricted CD8+ lymphocytes in the protection observed precisely at the same period in immunized mice remains to be elucidated. The authors also observe that immunization with the lipopeptidic form of the C-terminal peptide of the molecule (190-211 peptide) led to a CTL activation comparable to that observed after immunization with the whole molecule demonstrating the feasibility of using a synthetic lipopeptide as immunogen for a CTL response against Sm28GST epitopes. Moreover, like Sm28GST-specific CTLs, 190-211 lipopeptide-specific cells were also Class I MHC-restricted lymphocytes. [ABSTRACT FROM AUTHOR]

The data reviewed in this paper, suggest that besides their role in presentation of antigenic peptides to T cells, MHC-I molecules may play an important role in the fine-tuning of signal transmission across the cell membrane by their associations with a variety of cell-surface receptors regulating cell growth and differentiation. [ABSTRACT FROM AUTHOR]

In this paper the contribution of different accessory molecules to the adhesion of resting, naive and memory CD4+ T cells was examined utilizing a panel of CHO cell transfectants as model antigen-presenting cells (APCs). CD4+ T lymphocytes demonstrated strong adhesion to HLA-DR4 transfected CHO cells co-expressing B7, ICAM-1 or LFA-3 molecules, suggesting that all three adhesion pathways is utilized by resting CD4+ cells. Monoclonal antibodies (MoAbs) against the corresponding receptors on T cells, e.g. anti-CD28, anti-LFA-1β and anti-CD2. inhibited completely T-cell adhesion to natural ligands expressed on transfected CHO cells. Pretreatment of CD4+ T cells with NKI-L16 MoAb, which interact with an activation epitope on LFA-1α chain, enhanced adhesion to ICAM-1 but not B7 or LFA-3-expressing CHO cells. Analysis of T helper-cell subsets revealed that memory T cells bound several fold stronger to ICAM-1 expressing transfectants compared to the CD4+ 45RA+ naive T cells, whereas adhesion to B7, LFA-3- and B7/LFA-3-expressing CHO cells was similar in both T-cell subsets. The kinetics of adhesion of naive and memory CD4+ T cells to ICAM-1 was rapid and similar in both subsets. The NKI-L16 MoAb multiplied several times ICAM-1-dependent adhesion in naive compared to memory cells, which enabled the naive cells to reach a similar adhesion level as memory cells. The results suggest that resting naive CD4+ T cells utilize preferentially the CD2/LFA-3 or CD28/B7 adhesion pathways upon adhesion to APCs, while memory CD4+ T cells utilize the CD2/LFA-3, CD28/B7 and LFA-1/ICAM-1 adhesion pathways. The NKI-L16 MoAb-induced upregulation of adhesion involves an increased affinity of LFA-1 for its ligand and not a change in the number of LFA-1 molecules. This is compatible with a view that naive cells express a large number of inactive LFA-1 molecules, whereas memory cells express preferentially activated LFA-1 molecules. The inherent low number of active LFA-1 molecules on naive CD4+ T cells may be important in keeping these cells in a resting state. [ABSTRACT FROM AUTHOR]

This paper addresses the need for receptors involved in recirculation of T lymphocytes both during development and during an immune response or inflammation. Some known receptors present on T lymphocytes which are important in maintaining normal T-cell localization and function, i.e. the integrins, LECAMs, LPAM-1 and H-CAM (CD44) are considered in terms of the specificity which they confer on lymphocyte recirculation. A clear understanding of lymphocyte trafficking patterns and of the receptors involved may provide, for example, novel therapies for treatment of malignant cancer, alleviation of damage caused by lymphocytes during inflammatory responses, and targeting of cells to sites of infection. [ABSTRACT FROM AUTHOR]

The article presents abstracts of various research papers presented at the First International Conference on Synovitis: Characteristics and Functions of Synovial Cells Oslo, Norway, held on June 9-12, 1988. The article "The T Cell System in HA: Activated or Defective," by P.A. Bacon, focuses on Rheumatoid arthritis is classically viewed as a disease of lymphocyte activation occurring locally in the aynovium. Immunotoxins: A New Therapeutic Strategy for the Treatment of Rheumatoid Arthritis," by D.C. Blakey focuses on immunotoxins which are generally prepared by attaching the protein synthesis Inhibitory A-chain subunit of various plant toxins to monoclonal antibodies directed against cell specific antigens.

In this paper we demonstrate that the generation of cytotoxic T-cell hybridomas (CTH) that retain classically H-2 restricted and antigen-specific lytic activity is not generally feasible by fusion of cytotoxic T cells (CTL) with the AKR thymoma BW5147. However, CTH that express a nonspecific lytic activity are readily generated, as revealed by lectin-dependent assays. We analyse several such hybridomas for the nature of their lytic activity and for the expression of various function-associated T-cell molecules. We show that the lytic activity retained by CTH is atypical in that only P815 mastocytoma cells, and no other tumour targets, are lysedin the presence of phytohaemagglutinin (PHA), However, in other respects this lytic activity resembles that of normal CTL: it requires cellular contact, results in a reduction of the viability of the target cells, and is sensitive to both EDTA and low temperature. Lytic CTH express low amounts of T-cell antigen receptor (TCR), whereas non-lytic CTH have no detectable TCR on their surface. Most CTH, lytic or non-lytic, fail to express Lyt 2. We conclude that the loss of antigen specificity in CTH is due to reduced expression of T-cell antigen receptor as well as of other functionally relevant molecules. We further conclude from this work that a search for a better fusion partner may be indicated to facilitate the reliable production of cytotoxic T-cell hybridomas. [ABSTRACT FROM AUTHOR]

Highly polymorphic age-dependent differences in progression of T and B cells have been found in various strains of inbred mice. In the immune system of C57BL/6 mice these occur first in B cells and, later in life, in T cells In this paper, we have examined the progression in the functional capacity of C57BL/6 dendritic cells (DC). Age-dependent changes were found in the syngeneic mixed leucocyte reaction, in which the stimulatory capacity of OC increased with age. This increase was independent of the age of the donor of the serum that was added lo the culture, and occurred when young donors provided the T cells. Age-dependent changes in DC properties were not detected in terms of direct plaque-forming response, response lo concanavalin A, or in the allogeneic mixed leucocyte reaction. [ABSTRACT FROM AUTHOR]

Tumour-promoting phorbol diesters are mitogenic for lymphocytes and induce differentiation of B and T cell lines as well as promyelocytic leukaemia cells. This paper demonstrates that 12-O-tetradecanoyl-13-acetate (PMA), when cocultured with normal murine bone marrow cells (BMC), significantly augments an antigenic cell-surface determinant called 14D10. This antigen is present constitutively in the majority of bone-marrow lymphocytes of autoimmune lpr mice. PMA has little enhancing effect when cocultured with lpr BMC. In addition, Ia antigenic determinants are increased by PMA in normal but not lpr BMC. Retinoic acid (RA) and PMA act synergistically both to increase 14D10 and to enhance the stimulatory ability of target lymphocytes as measured by proliferation in an autologous mixed lymphocyte reaction (AMLR). We suggest that lpr mice have persistent expression of gene products like 14D10 that are usually repressed in normal adult mice. These gene products can be activated in normal mouse bone marrow by PMA which acts through a Ca2+-dependent phospholipid-dependent C protein kinase. The in vivo enhanced expression of 14D10 in lpr mice suggests activation by some mechanism or factors yet to be described. [ABSTRACT FROM AUTHOR]

We have developed a new assay for quantitative detection of all helper T cells that can induce normal B lymphocytes to proliferation and Ig secretion. To establish the optima] assay conditions, we have used cloned I helper cells of defined specificities that had previously been shown to activate normal B lymphocytes expressing the specific antigen(s) on direct cellular interactions. As shown in this paper, "irrelevant" B lymphocytes-that is, those that do not express either antigen or restriction elements recognized by the effector helper T cells-can also be induced in the presence of appropriate concentrations of pokeweed mitogen which are not mitogenic for the "target" B lymphocytes. 'Nonspecific" plaque-forming cell responses are of the same magnitude as those provided to specifically triggered targets and equal or better than those induced by lipopolysaecharide. The assay is highly sensitive and enables "semiquantitative' detection of less than 20-30 effector T cells per culture. Since effeetor helper T cells can be detected regardless of the clonal specificity, the assay appears useful for quantitative studies of various populations of T helper cells displaying mixed specificities and for the classification of cells with unknown functions. [ABSTRACT FROM AUTHOR]

The recirculation of lymphocytes through the tissues and their return to the blood were compared in nude and euthymic rats. Three approaches were used: the organ distribution of 15Cr-labelled lymphocytes from nude or euthymic donors at 24 h after injection; the compartmental distribution of B and T lymphocytes as assessed by autoradiography of the spleen, lymph nodes, and Peyer's patches; and the tempo of recirculation from blood to thoracic duct lymph as estimated by counting timed fractions of lymph from a recipient of labelled lymphocytes. The following conclusions were drawn: (1) The distribution of lymphocytes between organs and within organs is very similar in nude and euthymic recipients. In particular, B lymphocytes proceed normally to the follicular areas in the absence of T cells. (2) The recirculation from blood to lymph is delayed in nude rats. (3) For equal numbers of B and T cells injected intravenously about half as many B cells as T cells enter mesenteric and cervical lymph nodes, but approximately equal numbers of B and T cells enter the spleen and Peyer's patches. [ABSTRACT FROM AUTHOR]

Immune responsiveness of guinea pigs to dinitrophenyl-poly-L-lysine and to the lysine rich random co-polymer of L-glutamic acid and L-lysine are both controlled by a single gene, the `poly-L-Iysine gene'. This paper reviews recent experiments which demonstrate that these two antigens specifically compete with one another for being presented to T cells by the same antigen-presenting cells. This finding is interpreted to mean that antigens to which responsiveness is controlled by the same single gene compete for the Ir gene product of antigen-presenting cells. The review discusses if the products of the immune response genes-presumably the Ia antigens-may constitute a third specific antigen recognition system. It further speculates if this idea may help to provide insight into the phenomenon of histocompatibility-restriction and into the nature of the mixed leucocyte reaction. [ABSTRACT FROM AUTHOR]

Optimal proliferative response of T lymphocytes to purified protein derivative of tuberculin (PPD) in vitro requires that antigen be presented by autologous macrophages or allogeneic macrophages sharing HLA-D/DR determinants with the T cell donor. In some cases, however, T cells may respond to a limited extent to PPD in association with macrophages expressing different HLA-D/DR determinants. In this paper experiments are presented where various combinations of T cells and HLA-D/DR disparate macrophages were stimulated with PPD. We often found a strong PPD-specific response in HLA-D/DR-incompatible combinations in which the macrophages carried HLA-DR antigens known from serological studies to be cross-reactive with those of the T cell donor than in combinations in which this was not the case. Thus, the cross-reactions detected by serology may sometimes be reflected on a functional level in T lymphocyte/macrophages cooperation. [ABSTRACT FROM AUTHOR]

The proliferative response of sensitized human T cells to low concentrations of purified protein derivative of tuberculin (PPD) in vitro has previously been shown to depend on the presence of autologous or HLA-D-compatible macrophages (M ϕ). In this paper we present evidence that the M ϕ/T cell interaction requires viable M ϕ and does not involve a soluble factor. T cells from neonates do not respond to PPD in our system, while M ϕ from neonates are able 10 present PPD to T cells from HLA-D matched sensitized adults. It is also demonstrated that the previously reported HLA-D restriction of T cell/M ϕ cooperation is not due to T cell mediated killing of allogeneic macrophages in vitro. [ABSTRACT FROM AUTHOR]

This paper describes a technique utilizing rosette formation with sheep red blood cells as a human T lymphocyte marker, and separation of T cells by rosette sedimentation. [ABSTRACT FROM AUTHOR]

This paper describes a T-cell targeting strategy based on the use of an antigen-monoclonal antibody heteroconjugate. A rat anti-idiotypic monoclonal antibody specific for a murine B-cell lymphoma was conjugated to the purified protein derivative (PPD) of tuberculin. This construct selectively delivered up to 4.5 &times 104 molecules of PPD onto each tumour cell. Targeted PPD was internalized for endosomal processing and was presented in association with the I-A class II restriction element to PPD-reactive T-helper (Th) cells. Activated Th cells were demonstrated to proliferate and secrete significant levels of tumour necrosis factor (TNF). Such lymphokine secretion was observed at a PPD concentration as low as 1 ng/mI. Despite the secretion of TNF, the S-cell lymphoma was found to be resistant to autonomous Th-mediated cytotoxicity. Targeted Th cells did, however, activate tumourcidal macrophages that subsequently mediated significant tumour cytostasis. Based on this observation, it is proposed that the targeting system described may be exploited as the basis for a future immunotherapeutic strategy. [ABSTRACT FROM AUTHOR]

Lectins can be used to detect changes in cell-surface glycosylation. In this paper we examine the lectin-binding characteristics of murine T cells as measured by flow cytometry. A large panel of labelled lectins was used to stain naive, activated and resting murine T cells. Some lectins did not detectably bind any T cells, some bound to all T cells and some bound to only a subset of splenic T cells. Three lectins which preferentially bind to previously activated T cells were identified: Bandeiraea simplicifolia BS-I, Bauhinia purpurea and Lycopersicon esculentum. In addition, two lectins were found to bind preferentially to activated T cells; Glycine max and Triticum vulgaris. Finally, no differences were found in the ability of a large panel of lectins to bind to Th1 and Th2 clones. Lectin binding may be a powerful tool for distinguishing naive, activated and memory T cells. [ABSTRACT FROM AUTHOR]

The experiments described in this paper have examined the migration of three fluorochrome-labelled T-lymphocyte subsets (CD4+, CD8+ and γδ+T19+) on a single passage from blood to lymph, through prescapular lymph nodes. Lymphocytes obtained from prescapular efferent lymph were labelled in vitro with fluorochrome and returned to the blood of the same animal. Over the next 2 days, lymph was continuously monitored and the cells in all collections, including the one used for intravenous infusion, were phenotyped and analysed by flow cytometry. Significant differences in the subset ratios between the infused, starting population and the recirculated population iodicated that CD4+ and γδ+T19+ lymphocytes are extracted by a resting lymph node at the same rate and that both are extracted at a faster rate than CD8+ lymphocytes. The results presented here also suggest that a unique subset of γδ+T19+ lymphocytes may be present in blood that does not recirculate through peripheral lymph nodes. [ABSTRACT FROM AUTHOR]

The thoracic duct or efferent prescapular duct was cannulated in four fetal calves aged 121-259 days post-conception. The duration of lymph flow ranged from 2 to 20 days and the mean flow rates sustained over these collection periods varied from 54 to 488 ml/hr. Lymphocyte output ranged from 44 × 106 cells/hr in thoracic duct lymph from a 121-day fetus to 3.9 × 108 cells/hr in efferent prescapular lymph from a 259-day fetus. The circulating lymphocyte pool in fetal calves of about 120 and 190 days gestational age was calculated to contain, respectively, 4 × 108 cells and 2 × 1010 cells. The proportion of lymphocytes bearing surface immunoglobulin detected in fetal lymph ranged from 2.1% to 8.7%. Recirculating lymphocytes from fetal calves produced strong proliferative responses when stimulated by T-cell mitogens but responded poorly to B-cell mitogens. Fetal lymphocytes also responded to stimulation by allogeneic cells and stimulated other cells to proliferate during mixed lymphocyte culture. When stimulated with Con A, fetal lymphocytes secreted IL-2 to a degree that was indistinguishable from the secretory behaviour of lymphocytes from adult animals. The results presented in this paper show that chronic lymphatic fistulae can be established successfully in fetal calves to give access to recirculating lymphocytes. This provides a new experimental approach for studying the development of the bovine immune system. [ABSTRACT FROM AUTHOR]

In different murine systems, delayed-type hypersensitivity (DTH) swelling responses at 24–48 hr after antigen challenge were preceeded by an early 2-hr swelling response. The 24-hr DTH response is thought to depend on this early (DTH-initiating) hypersensitivity response. In this paper we show that in the syngeneic DBA/2-SL2 routine turnout system only an early 2-hr swelling response can be evoked. This early hypersensitivity response was tumour specific and serotonin dependent. The early hypersensitivity response in contact hypersensitivity has been ascribed to antigen-specific T-cell factors. To test whether similar T-cell factors were involved in the early hypersensitivity response in this syngencic turnout system, we have transferred lymph node, spleen lymphocytes and scram from immunized mice into naive recipients. The serum was fractionated in two fractions, a 50,000–80,000 MW fraction, and a 120,000–190,000 MW fraction. In recipients of lymphocytes, total serum and the 50,000–80,000 MW fraction of the serum, an early hypersensitivity response can be evoked. So, these data suggest the involvement of specific T-cell factors in the development of an early hypersensitivity response against syngeneic tumour cells. Despite the development of an early (DTH initiating) hypersensitivity swelling response these immunized animals cannot develop a classical 24-hr swelling response. This absence of the 24-hr response in the presence of the 2-hr response is discussed in relation to the frequently observed immune suppression in tumour-bearing mice. [ABSTRACT FROM AUTHOR]

MRL-+, MRL-lpr and B6-lpr have been shown to be useful models in studying systemic lupus erythematosus. MRL-lpr and B6-lpr differ from their congenic counterparts by the presence and expression of the homozygous recessive lymphoproliferation (Ipr) gene. One manifestation of this gene is a massive Tall proliferation that results in a generalized lymphadenopathy in older animals. A paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigate the basis for this hypo responsiveness in antigen-induced activation of proliferation and antibody synthesis. We have demonstrated that spleen cells from both MRL-+ and MRL-lpr mice gave minimal stimulation in a one-way mixed lymphocyte reaction against allogeneic T cells. These findings were extended to include antigen-specific proliferation involving antigen that must be processed and presented to responder lymphocytes in a H-2 restricted manner. Thus, MRL- + and MRL-lpr spleen cells pulsed with ferredoxin also failed to stimulate ferredoxin-primed T cells from B10.Br animals in vitro. We then investigated whether any T-cell defect(s) was also contributing to this proliferative hyporesponsiveness. T lymphocytes from the spleen of MRL- +, 2-month-old MRL-lpr, and 6-month-old MRL-lpr were tested in a one-way mixed lymphocyte reaction. It was found that only the MRL- + T cells gave responses approaching normal, suggesting lpr gene involvement in T-cell non-responsiveness. This was confirmed by the demonstration of an age-onset T-cell proliferative hyporesponsiveness in B6. lpr mice. This lpr gene-linked non-responsiveness was also shown to extend to T-cell helper function in a positive allogeneic effect assay. We can conclude from these studies that antigenic non-responsiveness in MRL congenic mice can be explained by two defects: (i) the failure of antigen-presenting cells in MRL- + and MRL-lpr mice to provide the necessary signal(s) to immunocompetent T cells, this defect not being associated with the lpr gene, and (ii) the Ip gene controlled outgrowth of a unique T-cell population that cannot respond in our assay systems. [ABSTRACT FROM AUTHOR]

Previous work from this laboratory has shown that preimmunization of syngeneic hosts with Rous sarcoma virus (RSV)-transformed cells elicits a strong immune response against the growth of transplantable RSV sarcomas, mediated by T lymphocytes expressing the surface phenotype of helper cell precursors (Prat, Di Renzo & Comoglio, 1983). This paper shows that anti-tumour immunity may be elicited in tumour-bearing animals by triggering an experimentally pre-amplified T-helper cell population at the site of tumour growth. Mice were treated with cyclophosphamide (which inactivates suppressor T cells) followed by skin sensitization to trinitrochlorobenzene (TNCB) according to a protocol that has been shown to induce an appreciably amplified generation of trinitrophenyl (TNP)-reactive helper T cells (Fujiwara et al., 1984). Five weeks after TNCB painting, mice were transplanted s.c. with a lethal dose of RSV-induced syngeneic sarcoma cells; the injection at the tumour site of TNCB induced the regression of the tumour in mice in which the TNP-helper cell population has been amplified, but not in controls, including those injected with a non-related hapten or sensitized to TNCB without inactivation of suppressors. [ABSTRACT FROM AUTHOR]

In this paper we present experiments that indicate that, in man, most T-celI subpopulations produce interleukin-2 (IL-2), but that the main cell subpopulation which produces it, both upon activation with phytohaemagglutinin or in autologous mixed lymphocyte cultures, is that of autologous rosette-forming (Tar) T4+ T cells. Conversely, the main IL-2-responding T-cell subpopulation is that composed of T cells depleted of Tar (T-Tar) that are T8+ IL-2 was also found to be more effectively produced by Tar cells that do not bind peanut agglutinin (PNA) than by those that do. The PNA T4+ Tar cells were also found to respond best to interleukin- I (IL-I). [ABSTRACT FROM AUTHOR]

This paper investigates desensitization in vitro, e.g. the inhibition of the transfer of contact sensitivity to picryl chloride by incubation of the passive transfer population with picrylated spleen cells. It asks whether desensitization is based on the same T-suppressor circuit which is responsible for the inhibition of passive transfer by antigen-specific T-suppressor factor (TsF). In this circuit, the T-suppressor cell which acts at the efferent stage (Ts-eff) makes TsF. This TsF depresses contact sensitivity indirectly by arming a T-acceptor cell (Tacc). The armed Tacc, when exposed to antigen (picrylated spleen cells), liberates a non-specific inhibitor which blocks the transfer of contact sensitivity. The three elements of this T-suppressor circuit occur in nylon wool-purified T cells prepared from the lymph nodes and spleens of mice four days after immunization with picryl chloride. This population transfers contact sensitivity and can be desensitized in vitro. It contains Ts-eff which can be isolated by panning (adherence) on picrylated albumin and detected by their ability to inhibit passive transfer. The 24 hr supernatant of cultures of these cells contains TsF. Finally the population contains Tacc which appear in the spleen 2 days after immunization and virtually disappear by 10 days. Further experiments demonstrated that the Ts-eff and the Tacc were not merely present but actually required for desensitization in vitro. Immune cells depleted of both Ts-eff (by panning on picrylated albumin) and Tacc (by arming with anti-oxazolone TsF and panning on oxazolonated albumin) cannot be desensitized. To restore desensitization both Ts-eff and Tacc must be added back. The Ts-eff were characterized as cyclophosphamide resistant, adult thymectomy sensitive cells (Cyr, ATx5), which adhered to antigen and were produced only by specific immunization. The Tacc were characterized as CF5, ATx5 cells which adhered to antigen only after arming with antigen-specific T-suppressor factor and were produced after immunization with an unrelated contact sensitizer, 'oxazolone'. It was concluded that desensitization in vitro was due to the interaction of two distinct T cells: the T-suppressor cell which acts at the efferent stage of the contact sensitivity reaction and the T-acceptor cell which becomes armed with the specific T-suppressor factor produced by the Ts-eff. [ABSTRACT FROM AUTHOR]

Sera from mice with large tumours from a variety of tissue types and sources have been shown to contain substances capable of suppressing the proliferative response of normal mouse lymphocytes to concanavalin A (Con A), bacterial endotoxin (LPS) and allogeneic cells. The present paper deals with studies on the nature of these inhibitory materials using mainly a methylcholanthreneinduced rhabdomyosarcoma in DBA/2J mice. It was found that a material responsible for inhibition of the Con A response eluted with immunoglobulins on Sephadex G-150 and eluted with monomeric immunoglobulin on Sephadex G-200. The component of tumour-bearer serum responsible for the suppression of the LPS response of normal lymphocytes eluted from Sephadex G-150 with the α and β globulins and albumin (molecular weight < 150,000). The immunoglobulin-containing serum fraction from tumour-bearing animals inhibited the mixed lymphocyte response, Con A response, and specific immune response to purified protein derivative (PPD) in allogeneic cell systems. It also inhibited the in vitro primary response of mouse cells to sheep red blood cells, and, to a lesser extent, the response to a T cell-independent antigen (DNP-dextran). The inhibitory activity continued to elute with monomeric IgG on Sephadex G-200 when columns were run in 1640 medium and adjusted to pH 2.5, indicating that an acid dissociable complex was not responsible for inhibitory activity. Inhibitor activity could be removed by absorption on immunoadsorbents containing goat anti-mouse immunoglobulin, and could be recovered by acid elution from the adsorbent. Inhibitor activity was not removed by immunoadsorption on columns prepared with antisera to chicken immunoglobulin. [ABSTRACT FROM AUTHOR]

Presents several abstracts for papers presented at the British Society for Investigative Dermatology Annual Meeting at the Oxford University in Oxford, England. "Lymphocyte Chemotactic Factor Produced by Cultured Human Keratinocytes," by A. C. Chu and J. Morris; "In vivo Detection of Interleukin-I-Like Activity in Normal Human Skin and Cutaneous T-cell Lymphoma," by J. A. Miller, P. M. Dowd, B. N. Hudspith, J. Brostoff, R. M. Barr, and M. W. Greaves; "Cell Mediated Immune Mechanisms in Atopic Dermatitis," by P. F. Dupuy, L. W. Poulter, C. B. Zachary, and D. M. MacDonald.

Introduction: Melanoma is a common and aggressive type of skin cancer with rising incidence rate globally. Gender is one of the determining factors, and overall males have a higher risk of developing melanoma as well as worse prognosis. Emerging evidence show that GPR68, a G protein-coupled receptor that is sensitive to acid and mechanical stimulations for cellular microenvironment, plays an important role in tumor biology. However, whether GPR68 is involved in gender-dependent regulation of tumor growth is unclear. Methods: We established a syngeneic melanoma model in Gpr68-deficient mice and investigated tumor growth in males and females. The GPR68 activation-induced cellular responses of melanocytes, including intracellular calcium dynamics, proliferation and migration were measured. The landscape of tumor-infiltrating immune cells were analyzed by flow cytometry and the expression various cytokines were checked by qRT-PCR. Results: GPR68 is required for melanoma growth in males but dispensable in females. GPR68 is expressed and functional in B16-F10 melanocytes, but the activity of the receptor does not directly contribute to proliferation and migration of the cells. GPR68 inhibits infiltration of CD45+ lymphocytes, CD8+ T cells and NK cells in melanoma in male mice, but has no apparent effect in females. Furthermore, GPR68 functionally inhibits the expression of IFNγ in the tumor infiltrating CD8+ T cells and NK cells as well as the inflammatory cytokine expression in the spleen in male mice but not in females. Our results show the gender-dependent modulatory effect of GPR68 on tumor-infiltrating immune cells and their tumor-killing capacity. Discussion: GPR68 is sensor for acid and mechanical stimulations, which are two important factors in the microenvironment associated with tumor growth and metastasis. Our results suggest a prominent role of the receptor molecules in tumor biology in a gender-dependent manner. Since GPCRs are more feasible to develop small molecule drugs compared to transcription factors, our study demonstrates the potential of GPR68 as a novel druggable therapeutic target for melanoma in male patients. [ABSTRACT FROM AUTHOR]

Over the past decades, it has become increasingly clear that higher order chromatin folding and organization within the nucleus is involved in the regulation of genome activity and serves as an additional epigenetic mechanism that modulates cellular functions and gene expression programs in diverse biological processes. In particular, dynamic allelic interactions and nuclear locations can be of functional importance during the process of lymphoid differentiation and the regulation of immune responses. Analyses of the proximity between chromatin and/or nuclear regions can be performed on populations of cells with high-throughput sequencing approaches such as chromatin conformation capture ("3C"-based) or DNA adenine methyltransferase identification (DamID) methods, or, in individual cells, by the simultaneous visualization of genomic loci, their primary transcripts and nuclear compartments within the 3-dimensional nuclear space using Fluorescence In Situ Hybridization (FISH) and immunostaining. Here, we present a detailed protocol to simultaneously detect nascent RNA transcripts (3D RNA FISH), their genomic loci (3D DNA FISH) and/or their chromosome territories (CT paint DNA FISH) combined with the antibody-based detection of various nuclear factors (immunofluorescence). We delineate the application and effectiveness of this robust and reproducible protocol in several murine T lymphocyte subtypes (from differentiating thymic T cells, to activated splenic and peripheral T cells) as well as other murine cells, including embryonic stem cells, B cells, megakaryocytes and macrophages. [ABSTRACT FROM AUTHOR]

T-cell large granular lymphocyte leukemia (T-LGL) is often accompanied by pure red cell aplasia (PRCA). A high depth of next generation sequencing (NGS) was used for detection of the mutational profiles in T-LGL alone (n = 25) and T-LGL combined with PRCA (n = 16). Beside STAT3 mutation (41.5%), the frequently mutated genes included KMT2D (17.1%), TERT (12.2%), SUZ12 (9.8%), BCOR (7.3%), DNMT3A (7.3%), and RUNX1 (7.3%). Mutations of the TERT promoter showed a good response to treatment. 3 of 41 (7.3%) T-LGL patients with diverse gene mutations were revealed as T-LGL combined with myelodysplastic syndrome (MDS) after review of bone marrow slide. T-LGL combined with PRCA showed unique features (low VAF level of STAT3 mutation, low lymphocyte count, old age). Low ANC was detected in a STAT3 mutant with a low level of VAF, suggesting that even the low mutational burden of STAT3 is sufficient for reduction of ANC. In retrospective analysis of 591 patients without T-LGL, one MDS patient with STAT3 mutation was revealed to have subclinical T-LGL. T-LGL combined with PRCA may be classified as unique subtype of T-LGL. High depth NGS can enable sensitive detection of concomitant MDS in T-LGL. Mutation of the TERT promoter may indicate good response to treatment of T-LGL, thus, its addition to an NGS panel may be recommended. [ABSTRACT FROM AUTHOR]

Simple Summary: Currently, multiple myeloma is mostly an incurable disease. Given the poor survival and frequent disease relapses, there is an urgent need for new treatment approaches and patient stratification. In an attempt to predict response to treatment, we comprehensively analyzed the immune profiles of longitudinal bone marrow samples collected from 18 multiple myeloma patients, separating them into good and poor responders to therapy. We identified several distinctive features that might have an influence on the therapy response, such as the abundance of tumor cells and the functional state of T and NK cells. These results suggest that deep immune profiling could be used for the guidance of treatment. The bone marrow microenvironment interacts with malignant cells and regulates cancer survival and immune evasion in multiple myeloma (MM). We investigated the immune profiles of longitudinal bone marrow samples from patients with newly diagnosed MM (n = 18) using cytometry by time-of-flight. The results before and during treatment were compared between patients with good (GR, n = 11) and bad (BR, n = 7) responses to lenalidomide/bortezomib/dexamethasone-based treatment. Before treatment, the GR group had a lower tumor cell burden and a higher number of T cells with a phenotype shifted toward CD8+ T cells expressing markers attributed to cytotoxicity (CD45RA and CD57), a higher abundance of CD8+ terminal effector cells, and a lower abundance of CD8+ naïve T cells. On natural killer (NK) cells, increased expression of CD56 (NCAM), CD57, and CD16 was seen at baseline in the GR group, indicating their maturation and cytotoxic potential. During lenalidomide-based treatment, the GR patients showed an increase in effector memory CD4+ and CD8+ T-cell subsets. These findings support distinct immune patterns in different clinical contexts, suggesting that deep immune profiling could be used for treatment guidance and warrants further exploration. [ABSTRACT FROM AUTHOR]

Graves' disease (GD) is a thyroid-specific autoimmune disease with a high prevalence worldwide. The disease is primarily mediated by B cells, which produce autoantibodies against the thyroid-stimulating hormone receptor (TSHR), chronically stimulating it and leading to high levels of thyroid hormones in the body. Interest in characterizing the immune response in GD has motivated many phenotyping studies. The immunophenotype of the cells involved and the interplay between them and their secreted factors are crucial to understanding disease progression and future treatment options. T cell populations are markedly distinct, including increased levels of Th17 and follicular helper T cells (Tfh), while Treg cells appear to be impaired. Some B cells subsets are autoreactive, and anti-TSHR antibodies are the key disease-causing outcome of this interplay. Though some consensus across phenotyping studies will be discussed here, there are also complexities that are yet to be resolved. A better understanding of the immunophenotype of Graves' disease can lead to improved treatment strategies and novel drug targets. [ABSTRACT FROM AUTHOR]

Endometriosis is a benign, chronic inflammatory disease that presents alterations in immune response that can be detected in eutopic endometrium, peritoneal fluid and peripheral blood of affected women. Regulatory T (T Reg ) cells are a subpopulation of T lymphocytes specialized in immune regulation that seem to participate in the development of endometriosis, by suppressing the immune response and favoring the establishment of lesions. Our aim was to review the scientific literature that evaluates T Reg cell phenotypes in the context of endometriosis. PRISMA statement for systematic reviews was applied, using “regulatory T cells” and “endometriosis” as keywords in the following databases: PubMed, Cochrane, EMBASE and Lilacs. The initial search and abstract review yielded 41 papers relating to the subject. At the end, 12 studies, published between 2009 and 2016, were included. Most studies that analyzed T Reg cells did not characterize these cells with current Bona Fide markers. In peritoneal fluid and endometriotic lesions, there was a higher concentration of T Reg cell phenotype and/or T Reg cell expression markers in patients with endometriosis when compared with controls. However, there is still not a consensus about T Reg cells concentration in eutopic endometrium and peripheral blood between the revised studies. Taken together, this data collection suggests that endometriosis is related to T Reg cells alterations, although further studies are necessary to reach more precise conclusions, especially regarding the percentage of these cells in eutopic endometrium and peripheral blood. This systematic review attempted to provide instructive and up-to-date collection of data that may help better design future studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Flow cytometry is a technique that allows identifying different cell populations based on their morphological characteristics and the presence of proteins in the membrane or inside the cell. It is widely used in biomedical research and clinical diagnosis; however, in the veterinary area, its use has been limited due to the reduced availability of fluorochrome-conjugated antibodies that recognize specific proteins. In order to implement multiparametric analyses in the study of bovine tuberculosis, this work designed two panels composed of different conjugates and tested them to identify helper, cytotoxic, activated, and memory T cells in heifers positively and negatively tested for tuberculin (diagnostic test for bovine tuberculosis). Both panels allowed the identification of the cells of interest; in addition, a higher number of activated and memory cells were observed in tuberculin-positive heifers. These panels can also be used in immunopathogenesis studies, as well as in the evaluation of vaccines in cattle. Flow cytometry (FC) is widely used in microbiology, immunology, hematology, and oncology. In the veterinary field, FC enabled the study of the immune response in cattle infected with different pathogens, as well as vaccine testing. However, few fluorochrome-conjugated antibodies recognize bovine antigens, limiting the possible benefits of FC and the implementation of multiparametric analysis for more complex studies. Two cytometry panels with five colors each were designed and implemented for the study and identification of populations and subpopulations of T cells derived from the peripheral blood mononuclear cells of dairy heifers. Both panels detected differences in T cell subpopulations between heifers positively and negatively tested for tuberculin; they detected overexpression of CD25+ and CD45RO+ in tuberculin-positive heifers after stimulation with a culture filtrate protein extract (CFPE) from Mycobacterium bovis (M. bovis). We identified subpopulations of T cells from peripheral blood mononuclear cells using two multicolor panels. These panels could be used to analyze total bovine blood in immunopathogenic studies and vaccine development. The same strategy could be implemented in other species of veterinary interest. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndrome (MDS) immunity plays an important role in the proliferation and apoptosis of aberrant cells. Immune dysregulation has been studied in various prognostic subgroups. This study analyzed 60 patients with MDS via multidimensional flow cytometry to evaluate the expression of aberrant markers, such as CD7 and cytoplasmic CD3 on lymphocytes. The Revised International Prognostic Scoring System (IPSS-R) scores were used to classify the patients into risk groups. The results showed a significant downregulation of CyCD3− T cells in low–intermediate versus high-risk patients (p = 0.013). This study is the first to show that a significant decrease in cyCD3− T cells in patients with a lower IPSS-R score may indicate microenvironmental changes conducive to transformation in MDS [ABSTRACT FROM AUTHOR]