Search

The recirculation of naive lymphocytes from blood to lymph that is initiated in high endothelial venules (HEV) of secondary lymphoid organs such as lymph nodes and Peyer's patches (PP) is regulated by multiple interactions of adhesion receptor/counter-receptor pairs involving both selectins and integrins. We showed previously that blocking of only L-selectin is sufficient to ablate trafficking of naive CD4 cells and the development of their responses in peripheral lymph nodes but not in PP where α4β7 integrins are thought to primarily regulate entry. However, although antibody to α4 integrins partially inhibited homing of naive CD4 cells to PP and not to lymph nodes, there was no effect on the development primary responses in these tissues or spleens. Since previous studies indicate that both α4β7 integrins and L-selectin regulate adhesion of naive cells to PP HEV, we examined the effect a blockade of both adhesion pathways on the circulation of naive CD4 cells. There was no detectable homing of naive CD4 cells to PP or lymph nodes when interactions with both receptors were inhibited, resulting in a profound depletion of naive CD4 cells and loss of antigen responses in these sites. In contrast, increased numbers of naive CD4 cells and responses of higher magnitude were found in the spleen. The results demonstrate recirculation of naive CD4 cells through tissues where entry is controlled through HEV is essential for the local generation of primary responses. [ABSTRACT FROM PUBLISHER]

Cellular components of the tumor microenvironment, including myeloid cells, play important roles in the progression of lung adenocarcinoma (LUAD) and its response to therapy. Here, we characterize the function of the ubiquitin ligases Siah1a/2 in regulating the differentiation and activity of alveolar macrophages (AM) and assess the implication of Siah1a/2 control of AMs for carcinogen-induced LUAD. Macrophage-specific genetic ablation of Siah1a/2 promoted accumulation of AMs with an immature phenotype and increased expression of protumorigenic and pro-inflammatory Stat3 and β-catenin gene signatures. Administration of urethane to wild-type mice promoted enrichment of immature-like AMs and lung tumor development, which was enhanced by macrophage-specific Siah1a/2 ablation. The profibrotic gene signature seen in Siah1a/2-ablated immature-like macrophages was associated with increased tumor infiltration of CD14+ myeloid cells and poorer survival of patients with LUAD. Single-cell RNA-seq confirmed the presence of a cluster of immature-like AMs expressing a profibrotic signature in lungs of patients with LUAD, a signature enhanced in smokers. These findings identify Siah1a/2 in AMs as gatekeepers of lung cancer development., Significance: The ubiquitin ligases Siah1a/2 control proinflammatory signaling, differentiation, and profibrotic phenotypes of alveolar macrophages to suppress lung carcinogenesis., (©2023 American Association for Cancer Research.)

PSGL-1 (P-selectin glycoprotein-1) is a T cell-intrinsic checkpoint regulator of exhaustion with an unknown mechanism of action. Here, we show that PSGL-1 acts upstream of PD-1 and requires co-ligation with the T cell receptor (TCR) to attenuate activation of mouse and human CD8 + T cells and drive terminal T cell exhaustion. PSGL-1 directly restrains TCR signaling via Zap70 and maintains expression of the Zap70 inhibitor Sts-1. PSGL-1 deficiency empowers CD8 + T cells to respond to low-affinity TCR ligands and inhibit growth of PD-1-blockade-resistant melanoma by enabling tumor-infiltrating T cells to sustain an elevated metabolic gene signature supportive of increased glycolysis and glucose uptake to promote effector function. This outcome is coupled to an increased abundance of CD8 + T cell stem cell-like progenitors that maintain effector functions. Additionally, pharmacologic blockade of PSGL-1 curtails T cell exhaustion, indicating that PSGL-1 represents an immunotherapeutic target for PD-1-blockade-resistant tumors., Competing Interests: Declaration of interests L.M.B. and R.T. hold patents for PSGL-1 modulators and uses thereof (US10858436B2, WO2016007653A3). L.M.B. and J.L.H. hold patents for PSGL-1 antagonists and uses thereof (63/481570)., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Immune suppressive factors of the tumor microenvironment (TME) undermine viability and exhaust the activities of the intratumoral cytotoxic CD8 + T lymphocytes (CTL) thereby evading anti-tumor immunity and decreasing the benefits of immune therapies. To counteract this suppression and improve the efficacy of therapeutic regimens, it is important to identify and understand the critical regulators within CD8 + T cells that respond to TME stress and tumor-derived factors. Here we investigated the regulation and importance of activating transcription factor-4 (ATF4) in CTL using a novel Atf4 ΔCD8 mouse model lacking ATF4 specifically in CD8 + cells. Induction of ATF4 in CD8 + T cells occurred in response to antigenic stimulation and was further increased by exposure to tumor-derived factors and TME conditions. Under these conditions, ATF4 played a critical role in the maintenance of survival and activities of CD8 + T cells. Conversely, selective ablation of ATF4 in CD8 + T cells in mice rendered these Atf4 ΔCD8 hosts prone to accelerated growth of implanted tumors. Intratumoral ATF4-deficient CD8 + T cells were under-represented compared to wild-type counterparts and exhibited impaired activation and increased apoptosis. These findings identify ATF4 as an important regulator of viability and activity of CD8 + T cells in the TME and argue for caution in using agents that could undermine these functions of ATF4 for anti-cancer therapies., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Different factors may lead to hepatitis. Among which are liver inflammation and poisoning. We chose two hepatitis models, typical for these two underlying causes. Thus, we aimed to characterize the role of protease-activated receptor 2 (Par2) in liver regeneration and inflammation to reconcile Par2 conflicting role in many damage models, which sometimes aggravates the induced damage and sometimes alleviates it., Methods: WT and knockout (Par2KO) mice were injected with concanavalin A (ConA) to induce immune-mediated hepatitis or with carbon tetrachloride (CCl 4 ) to elicit direct hepatic damage. To distinguish the immune component from the liver regenerative response, we conducted bone marrow (BM) replacements of WT and Par2KO mice and repeated the damage models., Results: ConA injection caused limited damage in Par2KO mice livers, while in the WT mice severe damage followed by leukocyte infiltration was evident. Reciprocal BM replacement of WT and Par2KO showed that WT BM-reconstituted Par2KO mice displayed marked liver damage, while in Par2KO BM-reconstituted WT mice, the tissue was generally protected. In the CCl 4 direct damage model, hepatocytes regenerated in WT mice, whereas Par2KO mice failed to recover. Reciprocal BM replacement did not show significant differences in hepatic regeneration. In Par2KO mice, hepatitis was more apparent, while WT recovered regardless of the BM origin., Conclusions: We conclude that Par2 activation in the immune system aggravates hepatitis and that Par2 activation in the damaged tissue promotes liver regeneration. When we incorporate this finding and revisit the literature reports, we reconciled the conflicts surrounding Par2's role in injury, recovery, and inflammation., (© 2022. The Author(s).)

Predicting and disrupting transmission of human parasites from wildlife hosts or vectors remains challenging because ecological interactions can influence their epidemiological traits. Human schistosomes, parasitic flatworms that cycle between freshwater snails and humans, typify this challenge. Human exposure risk, given water contact, is driven by the production of free-living cercariae by snail populations. Conventional epidemiological models and management focus on the density of infected snails under the assumption that all snails are equally infectious. However, individual-level experiments contradict this assumption, showing increased production of schistosome cercariae with greater access to food resources. We built bioenergetics theory to predict how resource competition among snails drives the temporal dynamics of transmission potential to humans and tested these predictions with experimental epidemics and demonstrated consistency with field observations. This resource-explicit approach predicted an intense pulse of transmission potential when snail populations grow from low densities, i.e., when per capita access to resources is greatest, due to the resource-dependence of cercarial production. The experiment confirmed this prediction, identifying a strong effect of infected host size and the biomass of competitors on per capita cercarial production. A field survey of 109 waterbodies also found that per capita cercarial production decreased as competitor biomass increased. Further quantification of snail densities, sizes, cercarial production, and resources in diverse transmission sites is needed to assess the epidemiological importance of resource competition and support snail-based disruption of schistosome transmission. More broadly, this work illustrates how resource competition can sever the correspondence between infectious host density and transmission potential., Competing Interests: The authors declare no competing interest., (Copyright © 2022 the Author(s). Published by PNAS.)

MicroRNAs (miRNAs/miRs) are small, endogenous noncoding RNAs that are important post-transcriptional regulators with clear roles in the development of the immune system and immune responses. Using miRNA microarray profiling, we characterized the expression profile of naive and in vivo generated murine effector antiviral CD8 + T cells. We observed that out of 362 measurable mature miRNAs, 120 were differentially expressed by at least 2-fold in influenza-specific effector CD8 + CTLs compared with naive CD8 + T cells. One miRNA found to be highly downregulated on both strands in effector CTLs was miR-139. Because previous studies have indicated a role for miR-139-mediated regulation of CTL effector responses, we hypothesized that deletion of miR-139 would enhance antiviral CTL responses during influenza virus infection. We generated miR-139 -/- mice or overexpressed miR-139 in T cells to assess the functional contribution of miR-139 expression in CD8 + T cell responses. Our study demonstrates that the development of naive T cells and generation or differentiation of effector or memory CD8 + T cell responses to influenza virus infection are not impacted by miR-139 deficiency or overexpression; yet, miR-139 -/- CD8 + T cells are outcompeted by wild-type CD8 + T cells in a competition setting and demonstrate reduced responses to Listeria monocytogenes Using an in vitro model of T cell exhaustion, we confirmed that miR-139 expression similarly does not impact the development of T cell exhaustion. We conclude that despite significant downregulation of miR-139 following in vivo and in vitro activation, miR-139 expression is dispensable for influenza-specific CTL responses., (Copyright © 2022 by The American Association of Immunologists, Inc.)

Objective: To examine the role of employee, supervisor, and organizational support in the prediction of employee participation in wellness programs., Methods: Data were collected at two-time points (T1 and T2) from 194 Australian employees., Results: Hierarchical binary logistic regressions revealed that higher levels of employee and supervisor support for wellness at T1 each predicted T2 participation, and high supervisor support was more effective when organizational support was high and did not compensate for when organizational support was low. Employees with higher perceptions of T1 poor general health had a lower likelihood of T2 participation, and higher levels of T1 supervisor support was a further deterrent to participation., Conclusions: Different sources of support for wellness predict employee attendance at wellness programs and it is important to ensure that supervisor and organizational support are aligned., Competing Interests: Jimmieson, Smidt, and Bradley have no relationships/conditions/circumstances that present potential conflict of interest., (Copyright © 2021 American College of Occupational and Environmental Medicine.)

Effective T cell differentiation during acute virus infections leads to the generation of effector T cells that mediate viral clearance, as well as memory T cells that confer protection against subsequent reinfection. While inhibitory immune checkpoints have been shown to promote T cell dysfunction during chronic virus infections and in tumors, their roles in fine tuning the differentiation and responses of effector and memory T cells are only just beginning to be appreciated. We previously identified PSGL-1 as a fundamental regulator of T cell exhaustion that sustains expression of several inhibitory receptors, including PD-1. We now show that PSGL-1 can restrict the magnitude of effector T cell responses and memory T cell development to acute LCMV virus infection by limiting survival, sustaining PD-1 expression, and reducing effector responses. After infection, PSGL-1-deficient effector T cells accumulated to a greater extent than wild type T cells, and preferentially generated memory precursor cells that displayed enhanced accumulation and functional capacity in response to TCR stimulation as persisting memory cells. Although, PSGL-1-deficient memory cells did not exhibit inherent greater sensitivity to cell death, they failed to respond to a homologous virus challenge after adoptive transfer into naïve hosts indicating an impaired capacity to generate memory effector T cell responses in the context of viral infection. These studies underscore the function of PSGL-1 as a key negative regulator of effector and memory T cell differentiation and suggest that PSGL-1 may limit excessive stimulation of memory T cells during acute viral infection., 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 Tinoco, Neubert, Stairiker, Henriquez and Bradley.)

Repetitive elements (REs) compose ∼50% of the human genome and are normally transcriptionally silenced, although the mechanism has remained elusive. Through an RNAi screen, we identified FBXO44 as an essential repressor of REs in cancer cells. FBXO44 bound H3K9me3-modified nucleosomes at the replication fork and recruited SUV39H1, CRL4, and Mi-2/NuRD to transcriptionally silence REs post-DNA replication. FBXO44/SUV39H1 inhibition reactivated REs, leading to DNA replication stress and stimulation of MAVS/STING antiviral pathways and interferon (IFN) signaling in cancer cells to promote decreased tumorigenicity, increased immunogenicity, and enhanced immunotherapy response. FBXO44 expression inversely correlated with replication stress, antiviral pathways, IFN signaling, and cytotoxic T cell infiltration in human cancers, while a FBXO44-immune gene signature correlated with improved immunotherapy response in cancer patients. FBXO44/SUV39H1 were dispensable in normal cells. Collectively, FBXO44/SUV39H1 are crucial repressors of RE transcription, and their inhibition selectively induces DNA replication stress and viral mimicry in cancer cells., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Many immunotherapies act by enhancing the ability of cytotoxic T cells to kill tumor cells. Killing depends on T cell recognition of antigens presented by class I major histocompatibility complex (MHC-I) proteins on tumor cells. In this study, we showed that medulloblastomas lacking the p53 tumor suppressor do not express surface MHC-I and are therefore resistant to immune rejection. Mechanistically, this is because p53 regulates expression of the peptide transporter Tap1 and the aminopeptidase Erap1, which are required for MHC-I trafficking to the cell surface. In vitro, tumor necrosis factor (TNF) or lymphotoxin-β receptor agonist can rescue expression of Erap1, Tap1 and MHC-I on p53-mutant tumor cells. In vivo, low doses of TNF prolong survival and synergize with immune checkpoint inhibitors to promote tumor rejection. These studies identified p53 as a key regulator of immune evasion and suggest that TNF could be used to enhance sensitivity of tumors to immunotherapy.

Numerous independent studies link gut microbiota composition and disease and imply a causal role of select commensal microbes in disease etiology. In the gut, commensal microbiota or pathobionts secrete metabolites that underlie pathological conditions, often impacting proximal tissues and gaining access to the bloodstream. Here we focus on extrinsic and intrinsic factors affecting composition of gut microbiota and their impact on the immune system, as key drivers of anti-tumor immunity. In discussing exciting advances relevant to microbiome-tumor interaction, we note existing knowledge gaps that need to be filled to advance basic and clinical research initiatives., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Growing evidence supports the importance of gut microbiota in the control of tumor growth and response to therapy. Here, we select prebiotics that can enrich bacterial taxa that promote anti-tumor immunity. Addition of the prebiotics inulin or mucin to the diet of C57BL/6 mice induces anti-tumor immune responses and inhibition of BRAF mutant melanoma growth in a subcutaneously implanted syngeneic mouse model. Mucin fails to inhibit tumor growth in germ-free mice, indicating that the gut microbiota is required for the activation of the anti-tumor immune response. Inulin and mucin drive distinct changes in the microbiota, as inulin, but not mucin, limits tumor growth in syngeneic mouse models of colon cancer and NRAS mutant melanoma and enhances the efficacy of a MEK inhibitor against melanoma while delaying the emergence of drug resistance. We highlight the importance of gut microbiota in anti-tumor immunity and the potential therapeutic role for prebiotics in this process., Competing Interests: Declaration of Interests Z.A.R. is a co-founder and serves as a scientific advisor to Pangea Therapeutics. All other authors declare no competing interests. A patent application detailing the findings disclosed in this manuscript has been filed by SBP Discovery., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

The immune system, and in particular, cytotoxic CD8 + T cells (CTLs), plays a vital part in the prevention and elimination of tumors. In many patients, however, CTL-mediated tumor killing ultimately fails in the clearance of cancer cells resulting in disease progression, in large part due to the progression of effector CTL into exhausted CTL. While there have been major breakthroughs in the development of CTL-mediated "reinvigoration"-driven immunotherapies such as checkpoint blockade therapy, there remains a need to better understand the drivers behind the development of T cell exhaustion. Our study highlights the unique differences in T cell exhaustion development in tumor-specific CTL which arises over time in a mouse model of mesothelioma. Importantly, we also show that peripheral tumor-specific T cells have a unique expression profile compared to exhausted tumor-infiltrating CTL at a late-stage of tumor progression in mice. Together, these data suggest that greater emphasis should be placed on understanding contributions of individual microenvironments in the development of T cell exhaustion., (Copyright © 2020 Hope, Spantidea, Kiernan, Stairiker, Rijsbergen, van Meurs, Brouwers-Haspels, Mueller, Nelson, Bradley, Aerts and Katsikis.)

Understanding the mechanisms underlying anti-tumor immunity is pivotal for improving immune-based cancer therapies. Here, we report that growth of BRAF-mutant melanoma cells is inhibited, up to complete rejection, in Siah2 -/- mice. Growth-inhibited tumors exhibit increased numbers of intra-tumoral activated T cells and decreased expression of Ccl17, Ccl22, and Foxp3. Marked reduction in Treg proliferation and tumor infiltration coincide with G1 arrest in tumor infiltrated Siah2 -/- Tregs in vivo or following T cell stimulation in culture, attributed to elevated expression of the cyclin-dependent kinase inhibitor p27, a Siah2 substrate. Growth of anti-PD-1 therapy resistant melanoma is effectively inhibited in Siah2 -/- mice subjected to PD-1 blockade, indicating synergy between PD-1 blockade and Siah2 loss. Low SIAH2 and FOXP3 expression is identified in immune responsive human melanoma tumors. Overall, Siah2 regulation of Treg recruitment and cell cycle progression effectively controls melanoma development and Siah2 loss in the host sensitizes melanoma to anti-PD-1 therapy.

Placenta percreta is the abnormal invasion of the placenta through the myometrium and serosa of the uterus. It is the most invasive of the placenta accreta spectrum followed by placenta increta. This paper presents a case of a maternal and fetal death in the second trimester due to rupture of the uterus at the site of placenta percreta in a C-section scar. Postmortem MRI showed a large hemoperitoneum and thinning of the anterolateral uterine wall. Internal examination revealed two liters of blood in the abdomen and rupture of the anterolateral uterine wall at the site of placenta percreta in a previous C-section scar. Placenta percreta is a rare complication of pregnancy, however, it is becoming more common with the increasing rate of C-section, the most common and significant risk factor.

Effective adaptive immune responses are characterized by stages of development and maturation of T and B cell populations that respond to disturbances in the host homeostasis in cases of both infections and cancer. For the T cell compartment, this begins with recognition of specific peptides by naïve, antigen-inexperienced T cells that results in their activation, proliferation, and differentiation, which generates an effector population that clears the antigen. Loss of stimulation eventually returns the host to a homeostatic state, with a heterogeneous memory T cell population that persists in the absence of antigen and is primed for rapid responses to a repeat antigen exposure. However, in chronic infections and cancers, continued antigen persistence impedes a successful adaptive immune response and the formation of a stereotypical memory population of T cells is compromised. With repeated antigen stimulation, responding T cells proceed down an altered path of differentiation that allows for antigen persistence, but much less is known regarding the heterogeneity of these cells and the extent to which they can become "memory-like," with a capacity for self-renewal and recall responses that are characteristic of bona fide memory cells. This review focuses on the differentiation of CD4 + and CD8 + T cells in the context of chronic antigen stimulation, highlighting the central observations in both human and mouse studies regarding the differentiation of memory or "memory-like" T cells. The importance of both the cellular and molecular drivers of memory T cell development are emphasized to better understand the consequences of persisting antigen on T cell fates. Integrating what is known and is common across model systems and patients can instruct future studies aimed at further understanding T cell differentiation and development, with the goal of developing novel methods to direct T cells toward the generation of effective memory populations.

Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5 -/- and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5 -/- mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5 -/- mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth.

Acquired perforating dermatosis (APD) is characterized by pruritic craterlike lesions with a predilection for patients affected by chronic kidney disease or diabetes mellitus (DM). We present a case of a 57-year-old black woman admitted for chest pain and dyspnea who was found to have 2 teardrop-shaped yellow-white-chalky plaques consistent with APD that developed at the site of a preexisting split-thickness skin graft (STSG). We also review the literature on APD.

Inflammatory bowel disease (IBD) is prevalent, but the mechanisms underlying disease development remain elusive. We identify a role for the E3 ubiquitin ligase RNF5 in IBD. Intestinal epithelial cells (IECs) express a high level of RNF5, while the colon of Rnf5 -/- mice exhibits activated dendritic cells and intrinsic inflammation. Rnf5 -/- mice exhibit severe acute colitis following dextran sodium sulfate (DSS) treatment. S100A8 is identified as an RNF5 substrate, resulting in S100A8 ubiquitination and proteasomal-dependent degradation that is attenuated upon inflammatory stimuli. Loss of RNF5 from IECs leads to enhanced S100A8 secretion, which induces mucosal CD4 + T cells, resulting in Th1 pro-inflammatory responses. Administration of S100A8-neutralizing antibodies to DSS-treated Rnf5 -/- mice attenuates acute colitis development and increases survival. An inverse correlation between RNF5 and S100A8 protein expression in IECs of IBD patients coincides with disease severity. Collectively, RNF5-mediated regulation of S100A8 stability in IECs is required for the maintenance of intestinal homeostasis., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Nuclear pore complexes (NPCs) are channels connecting the nucleus with the cytoplasm. We report that loss of the tissue-specific NPC component Nup210 causes a severe deficit of naïve CD4 + T cells. Nup210-deficient CD4 + T lymphocytes develop normally but fail to survive in the periphery. The decreased survival results from both an impaired ability to transmit tonic T cell receptor (TCR) signals and increased levels of Fas, which sensitize Nup210 -/- naïve CD4 + T cells to Fas-mediated cell death. Mechanistically, Nup210 regulates these processes by modulating the expression of Cav2 (encoding Caveolin-2) and Jun at the nuclear periphery. Whereas the TCR-dependent and CD4 + T cell-specific upregulation of Cav2 is critical for proximal TCR signaling, cJun expression is required for STAT3-dependent repression of Fas. Our results uncover an unexpected role for Nup210 as a cell-intrinsic regulator of TCR signaling and T cell homeostasis and expose NPCs as key players in the adaptive immune system.

T cells mediating influenza viral control are instructed in lymphoid and nonlymphoid tissues to differentiate into memory T cells that confer protective immunity. The mechanisms by which influenza virus-specific memory CD4 + T cells arise have been attributed to changes in transcription factors, cytokines and cytokine receptors, and metabolic programming. The molecules involved in these biosynthetic pathways, including proteins and lipids, are modified to varying degrees of glycosylation, fucosylation, sialation, and sulfation, which can alter their function. It is currently unknown how the glycome enzymatic machinery regulates CD4 + T cell effector and memory differentiation. In a murine model of influenza virus infection, we found that fucosyltransferase enzymatic activity was induced in effector and memory CD4 + T cells. Using CD4 + T cells deficient in the Fut4/7 enzymes that are expressed only in hematopoietic cells, we found decreased frequencies of effector cells with reduced expression of T-bet and NKG2A/C/E in the lungs during primary infection. Furthermore, Fut4/7 -/- effector CD4 + T cells had reduced survival with no difference in proliferation or capacity for effector function. Although Fut4/7 -/- CD4 + T cells seeded the memory pool after primary infection, they failed to form tissue-resident cells, were dysfunctional, and were unable to re-expand after secondary infection. Our findings highlight an important regulatory axis mediated by cell-intrinsic fucosyltransferase activity in CD4 + T cell effectors that ensure the development of functional memory CD4 + T cells., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Sweet syndrome (SS), also known as acute febrile neutrophilic dermatosis, is an uncommon condition that is clinically characterized by painful, well-demarcated, indurated, erythematous plaques or nodules that typically favor the head, neck, and arms, and are accompanied by fever. The disease is divided into several categories based on the underlying etiology, with the drug-induced variant comprising a rising number of the total cases and being reported in association with an increasing number of medications. We report a rare case of SS induced by an oral acetaminophen-codeine suspension and tablets. The importance of this case lies in the ability to educate both physicians and pharmacists alike regarding a newly recognized cutaneous adverse effect of acetaminophen-codeine so that the medication may be discontinued or substituted upon recognition of this adverse reaction to decrease patient morbidity.

P-selectin glycoprotein ligand-1 (PSGL-1) has long been studied as an adhesion molecule involved in immune cell trafficking and is recognized as a regulator of many facets of immune responses by myeloid cells. PSGL-1 also regulates T cell migration during homeostasis and inflammatory settings. However, recent findings indicate that PSGL-1 can also negatively regulate T cell function. Because T cell differentiation is finely tuned by multiple positive and negative regulatory signals that appropriately scale the magnitude of the immune response, PSGL-1 has emerged as an important checkpoint during this process. We summarize what is known regarding PSGL-1 structure and function and highlight how it may act as an immune checkpoint inhibitor in T cells., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Curing type 1 diabetes (T1D) will require lasting control of the autoimmune response that destroys insulin-producing islet β-cells. Re-establishing tolerance by restoring/replacing Tregs has significant potential for treatment of T1D but will require strategies to augment and maintain their efficacy. We previously showed that polyclonal in vitro-induced Tregs can reverse recent onset of T1D in ∼ 50% of NOD mice. Here we report that treatment of newly hyperglycemic animals with a short course of anti-CD44 at the time of Treg transfer improved diabetes reversal to >90%. Anti-CD44 treatment alone delayed diabetes onset and increased the frequencies of pancreatic CD4(+) T cells producing IL-2 or TGF-β, cytokines that support Treg function and survival, without altering production of IFN-γ. These anti-CD44 effects on endogenous T cells were also observed in the context of polyclonal Treg transfer, and the combination treatment also reduced pancreatic infiltrates. The results provide compelling evidence that approaches to modulate the pancreatic milieu to support Treg function and counteract inflammation in the pancreas can greatly enhance the efficacy of adoptively transferred Tregs, and suggest that approaches achieving these outcomes hold promise for long-term control of autoimmunity in T1D., (Copyright © 2014 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.)

Type I diabetes (T1D) is an autoimmune disease in which an immune response to pancreatic β-cells results in their loss over time. Although the conventional view is that this loss is due to autoimmune destruction, we present evidence of an additional phenomenon in which autoimmunity promotes islet endocrine cell transdifferentiation. The end result is a large excess of δ-cells, resulting from α- to β- to δ-cell transdifferentiation. Intermediates in the process of transdifferentiation were present in murine and human T1D. Here, we report that the peptide caerulein was sufficient in the context of severe β-cell deficiency to induce efficient induction of α- to β- to δ-cell transdifferentiation in a manner very similar to what occurred in T1D. This was demonstrated by genetic lineage tracing and time course analysis. Islet transdifferentiation proceeded in an islet autonomous manner, indicating the existence of a sensing mechanism that controls the transdifferentiation process within each islet. The finding of evidence for islet cell transdifferentiation in rodent and human T1D and its induction by a single peptide in a model of T1D has important implications for the development of β-cell regeneration therapies for diabetes.

Type 1 diabetes (T1D) results from autoimmune destruction of pancreatic β-cells. Although Th1 cells are key orchestrators of T1D, the function(s) of the more recently identified Th17 subset are unclear due to inherent plasticity. In this study, we analyzed Th17 cells for stability and diabetogenicity in NOD mice. We found that like Th1 cells, Th17 are a distinct population throughout the prediabetic phase. At diabetes onset, there were marked increases in IL-17-producing Th17 cells and IFN-γ-producing Th1 cells in the pancreas as well as in the serum levels of these cytokines, indicating that these proinflammatory mediators serve as biomarkers of advanced autoimmunity. Although naturally occurring Th17 cells in diabetic mice did not contribute to diabetes development in transfer models, islet-specific Th17 cells were diabetogenic independently of IL-17 and displayed inflammation-induced Th17-to-Th1 reprogramming that could be elicited by Th1 cells. However, an inability to generate Th1 cells because of Stat4, Ifngr, and Ifng deficiencies did not prevent diabetes. Instead, TNF-α could mediate diabetes in response to either Th17 cells or Th1 cells. The results identify a previously unknown mechanism by which Th17 cells can contribute to T1D. Our studies also suggest that when developing interventions for T1D, it will be potentially advantageous to focus on mechanisms common to effector T cells rather than on the signature cytokines of various subsets.

T cell migration is crucial for an effective adaptive immune response to invading pathogens. Naive and memory T cells encounter pathogen antigens, become activated, and differentiate into effector cells in secondary lymphoid tissues, and then migrate to the site(s) of infection where they exert effector activities that control and eliminate pathogens. To achieve activation, efficient effector function, and good memory formation, T cells must traffic between lymphoid and non-lymphoid tissues within the body. This complex process is facilitated by chemokine receptors, selectins, CD44, and integrins that mediate the interactions of T cells with the environment. The expression patterns of these migration receptors (MR) dictate the tissues into which the effector T cells migrate and enable them to occupy specific niches within the tissue. While MR have been considered primarily to facilitate cell movement, we highlight how the heterogeneity of signaling through these receptors influences the function and fate of T cells in situ. We explore what drives MR expression heterogeneity, how this affects migration, and how this impacts T cell effector function and memory formation.

Successful replication of the influenza A virus requires both viral proteins and host cellular factors. In this study we used a cellular assay to screen for small molecules capable of interfering with any of such necessary viral or cellular components. We used an established reporter assay to assess influenza viral replication by monitoring the activity of co-expressed luciferase. We screened a diverse chemical compound library, resulting in the identification of compound 7, which inhibits a novel yet elusive target. Quantitative real-time PCR studies confirmed the dose-dependent inhibitory activity of compound 7 in a viral replication assay. Furthermore, we showed that compound 7 is effective in rescuing high-dose influenza infection in an in vivo mouse model. As oseltamivir-resistant influenza strains emerge, compound 7 could be further investigated as a new and potentially suitable scaffold for the development of anti-influenza agents that act on novel targets., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Whether differences between naive cell-derived primary (1°) and memory cell-derived secondary (2°) CD4(+) T-cell effectors contribute to protective recall responses is unclear. Here, we compare these effectors directly after influenza A virus infection. Both develop with similar kinetics, but 2° effectors accumulate in greater number in the infected lung and are the critical component of memory CD4(+) T-cell-mediated protection against influenza A virus, independent of earlier-acting memory-cell helper functions. Phenotypic, functional, and transcriptome analyses indicate that 2° effectors share organ-specific expression patterns with 1° effectors but are more multifunctional, with more multicytokine (IFN-γ(+)/IL-2(+)/TNF(+))-producing cells and contain follicular helper T-cell populations not only in the spleen and draining lymph nodes but also in the lung. In addition, they express more CD127 and NKG2A but less ICOS and Lag-3 than 1° effectors and express higher levels of several genes associated with survival and migration. Targeting two differentially expressed molecules, NKG2A and Lag-3, reveals differential regulation of 1° and 2° effector functions during pathogen challenge.

Despite the widespread use of the cell-surface receptor CD44 as a marker for antigen (Ag)-experienced, effector and memory T cells, surprisingly little is known regarding its function on these cells. The best-established function of CD44 is the regulation of cell adhesion and migration. As such, the interactions of CD44, primarily with its major ligand, the extracellular matrix (ECM) component hyaluronic acid (HA), can be crucial for the recruitment and function of effector and memory T cells into/within inflamed tissues. However, little is known about the signaling events following engagement of CD44 on T cells and how cooperative interactions of CD44 with other surface receptors affect T cell responses. Recent evidence suggests that the CD44 signaling pathway(s) may be shared with those of other adhesion receptors, and that these provide contextual signals at different anatomical sites to ensure the correct T cell effector responses. Furthermore, CD44 ligation may augment T cell activation after Ag encounter and promote T cell survival, as well as contribute to regulation of the contraction phase of an immune response and the maintenance of tolerance. Once the memory phase is established, CD44 may have a role in ensuring the functional fitness of memory T cells. Thus, the summation of potential signals after CD44 ligation on T cells highlights that migration and adhesion to the ECM can critically impact the development and homeostasis of memory T cells, and may differentially affect subsets of T cells. These aspects of CD44 biology on T cells and how they might be modulated for translational purposes are discussed.

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing β-cells in the pancreatic islets. There is an immediate need to restore both β-cell function and immune tolerance to control disease progression and ultimately cure T1D. Currently, there is no effective treatment strategy to restore glucose regulation in patients with T1D. FoxP3-expressing CD4(+) regulatory T cells (Tregs) are potential candidates to control autoimmunity because they play a central role in maintaining self-tolerance. However, deficiencies in either naturally occurring Tregs (nTregs) themselves and/or their ability to control pathogenic effector T cells have been associated with T1D. Here, we hypothesize that nTregs can be replaced by FoxP3(+) adaptive Tregs (aTregs), which are uniquely equipped to combat autoreactivity in T1D. Unlike nTregs, aTregs are stable and provide long-lived protection. In this review, we summarize the current understanding of aTregs and their potential for use as an immunological intervention to treat T1D.

The early inflammatory response to influenza virus infection contributes to severe lung disease and continues to pose a serious threat to human health. The mechanisms by which neutrophils gain entry to the respiratory tract and their role during pathogenesis remain unclear. Here, we report that neutrophils significantly contributed to morbidity in a pathological mouse model of influenza virus infection. Using extensive immunohistochemistry, bone marrow transfers, and depletion studies, we identified neutrophils as the predominant pulmonary cellular source of the gelatinase matrix metalloprotease (MMP) 9, which is capable of digesting the extracellular matrix. Furthermore, infection of MMP9-deficient mice showed that MMP9 was functionally required for neutrophil migration and control of viral replication in the respiratory tract. Although MMP9 release was toll-like receptor (TLR) signaling-dependent, MyD88-mediated signals in non-hematopoietic cells, rather than neutrophil TLRs themselves, were important for neutrophil migration. These results were extended using multiplex analyses of inflammatory mediators to show that neutrophil chemotactic factor, CCL3, and TNFα were reduced in the Myd88⁻/⁻ airways. Furthermore, TNFα induced MMP9 secretion by neutrophils and blocking TNFα in vivo reduced neutrophil recruitment after infection. Innate recognition of influenza virus therefore provides the mechanisms to induce recruitment of neutrophils through chemokines and to enable their motility within the tissue via MMP9-mediated cleavage of the basement membrane. Our results demonstrate a previously unknown contribution of MMP9 to influenza virus pathogenesis by mediating excessive neutrophil migration into the respiratory tract in response to viral replication that could be exploited for therapeutic purposes.

Type 1 diabetes (T1D) develops as a consequence of a progressive autoimmune response that destroys insulin-producing β-cells in pancreatic islets. Because of their role(s) in controlling immune responses, considerable effort has been directed toward resolving whether regulatory T cells (Tregs) offer a clinical treatment to restore tolerance in T1D. We previously reported that in vitro-induced adaptive Treg cells (aTregs) can reverse T1D and persist as protective memory cells in the NOD mouse model. In the current study, we investigated mechanisms that regulate aTregs. We found that these FoxP3(+) aTregs expressed high levels of the IL-7 receptor, IL-7Rα, without the high affinity receptor for IL-2, CD25, which is found on natural Treg cells (nTregs). IL-7Rα expression was mirrored by the dependency of aTregs on IL-7 for persistence. IL-10 and TGF-β, effector cytokines of aTregs, were not essential for their maintenance at the level of systemic antibody blocking. Nevertheless, IL-10 modulated cytokine production by aTregs and TGF-β was critical for protection. aTregs were found to infiltrate islets and the expression of integrin-β7 was required for their localization in the pancreas. Furthermore, blocking aTreg entry into the pancreas prevented their control of diabetogenic effector T cells, implying the need for local control of the autoimmune response. The distinct homeostatic regulation of aTregs independently of a response to IL-2, which is defective in T1D patients, suggests that these cells represent a translatable candidate to control the autoimmune response., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

CD44 is a widely-expressed adhesion receptor that is associated with diverse biological processes involving migrating cells, including inflammation, angiogenesis, bone metabolism and wound healing. In the immune system, CD44 is upregulated after activation of naive T lymphocytes during their responses against invading microbes. Once an infection is cleared, elevated levels of CD44 remain on the surface of memory T cells that mediate protection against re-infection. While this has led to the use of highly sustained CD44 expression on T cells as an indicator of a previous immune response, the relevance to T-cell responses or homeostasis has been largely unexplored. Our recent studies demonstrate that CD44 selectively regulates the survival of the Th1 subset of CD4 T cells, but not other T-cell subpopulations. These findings, together with studies of CD44 in other cell types, suggest that differences in the engagement of signaling mechanisms are likely to underlie differential regulation of T-cell responses and underscore the importance of this adhesion receptor to immune cell regulation and protection against viruses and intracellular bacteria.

Optimal immunity to microorganisms depends upon the regulated death of clonally expanded effector cells and the survival of a cohort of cells that become memory cells. After activation of naive T cells, CD44, a widely expressed receptor for extracellular matrix components, is upregulated. High expression of CD44 remains on memory cells and despite its wide usage as a "memory marker," its function is unknown. Here we report that CD44 was essential for the generation of memory T helper 1 (Th1) cells by promoting effector cell survival. This dependency was not found in Th2, Th17, or CD8(+) T cells despite similar expression of CD44 and the absence of splice variants in all subsets. CD44 limited Fas-mediated death in Th1 cells and its ligation engaged the phosphoinositide 3-kinase-Akt kinase signaling pathway that regulates cell survival. The difference in CD44-regulated apoptosis resistance in T cell subpopulations has important implications in a broad spectrum of diseases., (Copyright 2010 Elsevier Inc. All rights reserved.)

Type 1 diabetes is a CD4 cell-dependent disease that results from destruction of insulin-producing beta cells in pancreatic islets. An ideal therapy would reverse diabetes shortly after onset when islet function in not yet fully ablated, and also prevent re-emergence of disease through the generation of memory cells that control the autoimmune response. In this study, we show that adaptive/induced polyclonal regulatory (TR) cells, which contain islet-reactive cells, fulfill these criteria in the NOD mouse model. CD4 cells induced to express FoxP3, IL-10, and TGF-beta1 in response to TCR signaling and TGF-beta1 can reverse diabetes with clinical restoration of prediabetic serum levels of IL-10. Unlike naturally occurring TR cells, these adaptive TR cells persist indefinitely (>1 year) as FoxP3(+), CD25(-) memory cells that self-renew. Establishment of memory is accompanied by narrowing of the T cell repertoire to usage of a single TCR beta-chain, Vbeta11, implying selection by Ag. With islet-specific adaptive TR cells, we show that memory is functionally stable and transferable. Therefore, adaptive TR cells, which can be readily generated from normal CD4 populations and become focused by Ag with induction of memory, may provide a treatment and a vaccine for the long-term cure of diabetes making them attractive as immunotherapeutic agents.

We previously established that exposure of the estrogen receptor (ER) alpha positive MCF-7 human breast cancer cell line to 17-beta-estradiol (E2) results in the post-confluent development of multilayered cellular aggregates (foci) which is consistent with the in vivo cancer phenotype of uncontrolled cellular proliferation. In this investigation, the interaction between the insulin-like growth factor receptor (IGF-IR) and ER-signaling systems in regard to post-confluent focus development was studied. We demonstrated that focus development requires the presence of E2 and insulin-like growth factor I (IGF-I) or insulin-like growth factor II (IGF-II), as well as intact ER and IGF-IR. Focus development in MCF-7 cultures, which occurs only after formation of a confluent monolayer, coincides with E2 regulation of key members of the IGF-signaling system such as IGF-IR, IGF-II, insulin receptor substrate 1 (IRS-1), and insulin-like growth factor binding protein 3 (IGFBP-3), as demonstrated by real-time polymerase chain reaction (PCR). To establish the relevancy of an intact IGF-signaling system for foci formation, we generated stable clones from MCF-7 with IGF-IR suppressed by siRNA. Results from these studies implicate signaling through the IGF-IR to be an integral requirement for E2-dependent post-confluent proliferation and focus formation. In summary, these studies establish the interactive roles of IGFs and E2 in the post-confluent development of foci, and will allow subsequent identification of targets for therapeutic intervention in the control and treatment of estrogen-dependent breast cancer.

Adaptive regulatory T cells that develop from naive CD4 cells in response to exposure to Ag can act as immunotherapeutic agents to control immune responses. We show that effectors generated from murine islet-specific CD4 cells by TCR stimulation with IL-2 and TGF-beta1 have potent suppressive activity. They prevent spontaneous development of type 1 diabetes in NOD mice and inhibit development of pancreatic infiltrates and disease onset orchestrated by Th1 effectors. These regulatory T cells do not require innate CD25+ regulatory cells for generation or function, nor do they share some characteristics typically associated with them, including expression of CD25. However, the adaptive population does acquire the X-linked forkhead/winged helix transcription factor, FoxP3, which is associated with regulatory T cell function and maintains expression in vivo. One mechanism by which they may inhibit Th1 cells is via FasL-dependent cytotoxicity, which occurs in vitro. In vivo, they eliminate Th1 cells in lymphoid tissues, where Fas/FasL interactions potentially play a role because Th1 cells persist when this pathway is blocked. The results suggest that adaptive regulatory CD4 cells may control diabetes in part by impairing the survival of islet-specific Th1 cells, and thereby inhibiting the localization and response of autoaggressive T cells in the pancreatic islets.

A coculture system was developed to investigate the interactions between MCF-10A breast epithelial cells and MCF-7 breast cancer cells stably expressing the green fluorescent protein (MCF-7-GFP). Studies with this MCF-10A/MCF-7-GFP coculture system on microtiter plates and on reconstituted basement membrane (Matrigel), revealed paracrine inhibition of MCF-7-GFP cell proliferation. Epidermal growth factor, which in monocultures modestly enhanced MCF-7-GFP and markedly increased MCF-10A cell proliferation, greatly inhibited MCF-7-GFP cell proliferation in MCF-10A/MCF-7-GFP cocultures. 17beta-Estradiol, which stimulated MCF-7-GFP but not MCF-10A cell proliferation in monoculture, inhibited MCF-7-GFP cell proliferation in MCF-10A/MCF-7-GFP cocultures, an effect that was blocked by the antiestrogen, ICI 182,780. On Matrigel, complex MCF-10A/MCF-7-GFP cellular interactions were observed in real time that resulted in the formation of acinus-like structures. These results indicate a role of normal epithelial cells in inhibiting tumor-cell proliferation and demonstrate the utility of this coculture system as a model of early paracrine control of breast cancer.

To track epitope-specific CD4(+) T cells at a single-cell level during influenza infection, the MHC class II-restricted OVA(323-339) epitope was engineered into the neuraminidase stalk of influenza/A/WSN, creating a surrogate viral antigen. The recombinant virus, influenza A/WSN/OVA(II), replicated well, was cleared normally, and stimulated both wild-type and DO11.10 or OT-II TCR transgenic OVA-specific CD4(+) T cells. OVA-specific CD4 T cells proliferated during infection only when the OVA epitope was present. However, previously primed (but not naive) transgenic CD4(+) T cells were recruited to the infected lung both in the presence and absence of the OVA(323-339) epitope. These data show that, when primed, CD4(+) T cells may traffic to the lung in the absence of antigen, but do not proliferate. These results also document a useful tool for the study of CD4 T cells in influenza infection.