Intradermal Fractional ChAdOx1 nCoV-19 Booster Vaccine Induces Memory T Cells: A Follow-Up Study

The administration of viral vector and mRNA vaccine booster effectively induces humoral and cellular immune responses. Effector T cell responses after fractional intradermal (ID) vaccination are comparable to those after intramuscular (IM) boosters. Here, we quantified T cell responses after booster vaccination. ChAdOx1 nCoV-19 vaccination induced higher numbers of S1-specific CD8+ memory T cells, consistent with the antibody responses. Effector memory T cell phenotypes elicited by mRNA vaccination showed a similar trend to those elicited by the viral vector vaccine booster. Three months post-vaccination, cytokine responses remained detectable, confirming effector T cell responses induced by both vaccines. The ID fractional dose of ChAdOx1 nCoV-19 elicited higher effector CD8+ T cell responses than IM vaccination. This study confirmed that an ID dose-reduction vaccination strategy effectively stimulates effector memory T cell responses. ID injection could be an improved approach for effective vaccination programs.

Replication-dead gammaherpesvirus vaccine protects against acute replication, reactivation from latency, and lethal challenge in mice

Gammaherpesviruses (GHVs) are oncogenic viruses that establish lifelong infections and are significant causes of human morbidity and mortality. While several vaccine strategies to limit GHV infection and disease are in development, there are no FDA-approved vaccines for human GHVs. As a new approach to gammaherpesvirus vaccination, we developed and tested a replication-dead virus (RDV) platform, using murine gammaherpesvirus 68 (MHV68), a well-established mouse model for gammaherpesvirus pathogenesis studies and preclinical therapeutic evaluations. We employed codon-shuffling-based complementation to generate revertant-free RDV lacking expression of the essential replication and transactivator protein (RTA) encoded by ORF50 to arrest viral gene expression early after de novo infection. Inoculation with RDV-50.stop exposes the host to intact virion particles and leads to limited lytic gene expression in infected cells. Prime-boost vaccination of mice with RDV-50.stop elicited virus-specific neutralizing antibody and effector T cell responses in the lung and spleen. Vaccination with RDV-50.stop resulted in a near complete abolishment of virus replication in the lung 7 days post-challenge and virus reactivation from spleen 16 days post-challenge with WT MHV68. Ifnar1-/- mice, which lack the type I interferon receptor, exhibit severe disease upon infection with WT MHV68. RDV-50.stop vaccination of Ifnar1-/- mice prevented wasting and mortality upon challenge with WT MHV68. These results demonstrate that prime-boost vaccination with a GHV that is unable to undergo lytic replication offers protection against acute replication, reactivation, and severe disease upon WT virus challenge.

[Advances in the Role of Low-Dose Interleukin-2 in Immune-Mediated Dermatosis]

Immune-mediated dermatoses are the skin diseases caused by the breakdown of immune tolerance,including lupus erythematosus and dermatomyositis.The imbalance between regulatory T cells (Tregs) and effector T cells (Teffs) plays a key role in the pathogenesis of these diseases.Low-dose interleukin-2 can preferentially activate Tregs and reverse the imbalance between Tregs and Teffs to recover the immune tolerance,which has attracted attention in the treatment of immune-mediated dermatoses.This review summarizes the research progress in the immunomodulatory mechanism and clinical application of low-dose interleukin-2 in immune-mediated dermatoses,providing a new idea for the clinical treatment of these diseases.

Cell-Intrinsic CD38 Expression Sustains Exhausted CD8+ T Cells by Regulating Their Survival and Metabolism during Chronic Viral Infection

Acute and chronic viral infections result in the differentiation of effector and exhausted T cells with functional and phenotypic differences that dictate whether the infection is cleared or progresses to chronicity. High CD38 expression has been observed on CD8+ T cells across various viral infections and tumors in patients, suggesting an important regulatory function for CD38 on responding T cells. Here, we show that CD38 expression was increased and sustained on exhausted CD8+ T cells following chronic lymphocytic choriomeningitis virus (LCMV) infection, with lower levels observed on T cells from acute LCMV infection. We uncovered a cell-intrinsic role for CD38 expression in regulating the survival of effector and exhausted CD8+ T cells. We observed increased proliferation and function of Cd38-/- CD8+ progenitor exhausted T cells compared to those of wild-type (WT) cells. Furthermore, decreased oxidative phosphorylation and glycolytic potential were observed in Cd38-/- CD8+ T cells during chronic but not acute LCMV infection. Our studies reveal that CD38 has a dual cell-intrinsic function in CD8+ T cells, where it decreases proliferation and function yet supports their survival and metabolism. These findings show that CD38 is not only a marker of T cell activation but also has regulatory functions on effector and exhausted CD8+ T cells. IMPORTANCE Our study shows how CD38 expression is regulated on CD8+ T cells responding during acute and chronic viral infection. We observed higher CD38 levels on CD8+ T cells during chronic viral infection compared to levels during acute viral infection. Deleting CD38 had an important cell-intrinsic function in ensuring the survival of virus-specific CD8+ T cells throughout the course of viral infection. We found defective metabolism in Cd38-/- CD8+ T cells arising during chronic infection and changes in their progenitor T cell phenotype. Our studies revealed a dual cell-intrinsic role for CD38 in limiting proliferation and granzyme B production in virus-specific exhausted T cells while also promoting their survival. These data highlight new avenues for research into the mechanisms through which CD38 regulates the survival and metabolism of CD8+ T cell responses to viral infections.

Impact of chronic alcohol exposure on conventional and regulatory murine T cell subsets

Introduction

Chronic alcohol use poses significant negative consequences to public health and, among its many biologic effects, is associated with significant T cell dysregulation within the adaptive immune system that has yet to be fully characterized. Novel, automated strategies for high dimensional flow cytometric analysis of the immune system are rapidly improving researchers' ability to detect and characterize rare cell types.

Methods

Using a murine model of chronic alcohol ingestion in conjunction with viSNE and CITRUS analysis tools, we performed a machine-driven, exploratory analysis comparing rare splenic subpopulations within the conventional CD4+, regulatory CD4+ and CD8+ T cell compartments between alcohol- and water-fed animals.

Results

While there were no differences in the absolute numbers of bulk CD3+ T cells, bulk CD4+ T cells, bulk CD8+ T cells, Foxp3- CD4+ conventional T cells (Tconv) or Foxp3+ CD4+ regulatory T cells (Treg), we identified populations of naïve Helios+ CD4+Tconv and naïve CD103+ CD8+ splenic T cells that were decreased in chronically alcohol exposed mice versus water-fed controls. In addition, we identified increased CD69+ Treg and decreased CD103+ effector regulatory T cell (eTreg) subsets in conjunction with increased frequency of a population that may represent a transitional phenotype between central regulatory T cell (cTreg) and eTreg.

Discussion

These data provide further resolution into the character of decreased naïve T cell populations known to be present in alcohol exposed mice, as well as describe alterations in effector regulatory T cell phenotypes associated with the pathogenesis of chronic alcohol-induced immune dysfunction.

Sirtuin 5 is Dispensable for CD8+ T Cell Effector and Memory Differentiation

CD8⁺ T cell effector and memory differentiation is tightly controlled at multiple levels including transcriptional, metabolic, and epigenetic regulation. Sirtuin 5 (SIRT5) is a protein deacetylase mainly located at mitochondria, but it remains unclear whether SIRT5 plays key roles in regulating CD8⁺ T cell effector or memory formation. Herein, with adoptive transfer of Sirt5^+/+ or Sirt5^−/− OT-1 cells and acute Listeria monocytogenes infection model, we demonstrate that SIRT5 deficiency does not affect CD8⁺ T cell effector function and that SIRT5 is not required for CD8⁺ T cell memory formation. Moreover, the recall response of SIRT5 deficient memory CD8⁺ T cells is comparable with Sirt5^+/+ memory CD8⁺ T cells. Together, these observations suggest that SIRT5 is dispensable for the effector function and memory differentiation of CD8⁺ T cells.

Emerging Complexity in CD4+T Lineage Programming and Its Implications in Colorectal Cancer

The intestinal immune system has the difficult task of protecting a large environmentally exposed single layer of epithelium from pathogens without allowing inappropriate inflammatory responses. Unmitigated inflammation drives multiple pathologies, including the development of colorectal cancer. CD4⁺T cells mediate both the suppression and promotion of intestinal inflammation. They comprise an array of phenotypically and functionally distinct subsets tailored to a specific inflammatory context. This diversity of form and function is relevant to a broad array of pathologic and physiologic processes. The heterogeneity underlying both effector and regulatory T helper cell responses to colorectal cancer, and its impact on disease progression, is reviewed herein. Importantly, T cell responses are dynamic; they exhibit both quantitative and qualitative changes as the inflammatory context shifts. Recent evidence outlines the role of CD4⁺T cells in colorectal cancer responses and suggests possible mechanisms driving qualitative alterations in anti-cancer immune responses. The heterogeneity of T cells in colorectal cancer, as well as the manner and mechanism by which they change, offer an abundance of opportunities for more specific, and likely effective, interventional strategies.

Optical Control of CD8+ T Cell Metabolism and Effector Functions

Although cancer immunotherapy is effective against hematological malignancies, it is less effective against solid tumors due in part to significant metabolic challenges present in the tumor microenvironment (TME), where infiltrated CD8+ T cells face fierce competition with cancer cells for limited nutrients. Strong metabolic suppression in the TME is often associated with impaired T cell recruitment to the tumor site and hyporesponsive effector function via T cell exhaustion. Increasing evidence suggests that mitochondria play a key role in CD8+ T cell activation, effector function, and persistence in tumors. In this study, we showed that there was an increase in overall mitochondrial function, including mitochondrial mass and membrane potential, during both mouse and human CD8+ T cell activation. CD8+ T cell mitochondrial membrane potential was closely correlated with granzyme B and IFN-γ production, demonstrating the significance of mitochondria in effector T cell function. Additionally, activated CD8+ T cells that migrate on ICAM-1 and CXCL12 consumed significantly more oxygen than stationary CD8+ T cells. Inhibition of mitochondrial respiration decreased the velocity of CD8+ T cell migration, indicating the importance of mitochondrial metabolism in CD8+ T cell migration. Remote optical stimulation of CD8+ T cells that express our newly developed "OptoMito-On" successfully enhanced mitochondrial ATP production and improved overall CD8+ T cell migration and effector function. Our study provides new insight into the effect of the mitochondrial membrane potential on CD8+ T cell effector function and demonstrates the development of a novel optogenetic technique to remotely control T cell metabolism and effector function at the target tumor site with outstanding specificity and temporospatial resolution.

Mechanisms That Underly T Cell Immunity in Graves' Orbitopathy

Graves' orbitopathy (GO), also known as thyroid-associated ophthalmopathy, is the most common ocular abnormality of Graves' disease. It is a disfiguring, invalidating, and potentially blinding orbital disease mediated by an interlocking and complicated immune network. Self-reactive T cells directly against thyroid-stimulating hormone receptor-bearing orbital fibroblasts contribute to autoimmune inflammation and tissue remodeling in GO orbital connective tissues. To date, T helper (Th) 1 (cytotoxic leaning) and Th2 (antibody leaning) cell subsets and an emerging role of Th17 (fibrotic leaning) cells have been implicated in GO pathogenesis. The potential feedback loops between orbital native residential CD34^- fibroblasts, CD34⁺ infiltrating fibrocytes, and effector T cells may affect the T cell subset bias and the skewed pattern of cytokine production in the orbit, thereby determining the outcomes of GO autoimmune reactions. Characterization of the T cell subsets that drive GO and the cytokines they express may significantly advance our understanding of orbital autoimmunity and the development of promising therapeutic strategies against pathological T cells.

Single-cell multi-omics analysis presents the landscape of peripheral blood T-cell subsets in human chronic prostatitis/chronic pelvic pain syndrome

Cumulative evidence suggests that abnormal differentiation of T lymphocytes influences the pathogenesis of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Thus, understanding the immune activation landscape of CP/CPPS would be helpful for improving therapeutic strategies. Here, we utilized BD™ AbSeq to digitally quantify both the protein and mRNA expression levels in single peripheral blood T cells from two CP/CPPS patients and two healthy controls. We utilized an integrated strategy based on canonical correlation analysis of 10 000+ AbSeq profiles and identified fifteen unique T‐cell subpopulations. Notably, we found that the proportion of cluster 0 in the CP/CPPS group (30.35%) was significantly increased compared with the proportion in the healthy control group (9.38%); cluster 0 was defined as effector T cells based on differentially expressed genes/proteins. Flow cytometry assays confirmed that the proportions of effector T‐cell subpopulations, particularly central memory T cells, T helper (Th)1, Th17 and Th22 cells, in the peripheral blood mononuclear cell populations of patients with CP/CPPS were significantly increased compared with those of healthy controls (P < 0.05), further confirming that aberration of effector T cells possibly leads to or intensifies CP/CPPS. Our results provide novel insights into the underlying mechanisms of CP/CPPS, which will be beneficial for its treatment.

Differential Requirement of Beclin 1 for Regulating the Balance of Naïve and Activated CD4+ T Cells

Autophagy is highly regulated and plays a multitude of roles during T cell-mediated immune responses. It has been shown that autophagy deficiency in T cells results in a decrease in total T cells, including naïve T cells in young mice, but the mechanism is still not understood. Here, similar to what happened in young mice, we showed that T cell-specific deletion of Beclin 1/Atg6 (Becn1 −/−) resulted in decreases in the percentages of CD4⁺, CD8⁺, and regulatory T cells in adult mice. In addition, we found that the effector to naïve T cell ratio was increased in older mice. Also, as mice grew older, Becn1 −/− mice progressively lost weight and developed severe colitis. Analysis of inflamed tissues demonstrated increases in the portion and cytokine production of effector T cells. In contrast, the TCR-transgenic Becn1 −/− mice had similar numbers of naïve T cells compared to WT controls. Similar to bulk T cells, the TCR-transgenic Becn1 −/− T cells generated much lower numbers of effector T cells compared to WT controls after activation in vitro. These data suggest that autophagy is not required for maintaining the naïve T cell but required for the generation of effector T cells in vivo.

Evidence for Associations Between Th1/Th17 "Hybrid" Phenotype and Altered Lipometabolism in Very Severe Graves Orbitopathy

PURPOSE

The purpose of this article is to investigate the characteristics of Th1-cell and Th17-cell lineages for very severe Graves orbitopathy (GO) development.

METHODS

Flow cytometry was performed with blood samples from GO and Graves disease (GD) patients and healthy controls, to explore effector T-cell phenotypes. Lipidomics was conducted with serum from very severe GO patients before and after glucocorticoid (GC) therapy. Immunohistochemistry and Western blotting were used to examine orbital-infiltrating Th17 cells or in vitro models of Th17 polarization.

RESULTS

In GD, Th1 cells predominated in peripheral effector T-cell subsets, whereas in GO, Th17-cell lineage predominated. In moderate-to-severe GO, Th17.1 cells expressed retinoic acid receptor-related orphan receptor-γt (RORγt) independently and produced interleukin-17A (IL-17A), whereas in very severe GO, Th17.1 cells co-expressed RORγt and Tbet and produced interferon-γ (IFN-γ). Increased IFN-γ-producing Th17.1 cells positively correlated with GO activity and were associated with the development of very severe GO. Additionally, GC therapy inhibited both Th1-cell and Th17-cell lineages and modulated a lipid panel consisting of 79 serum metabolites. However, in GC-resistant, very severe GO, IFN-γ-producing Th17.1 cells remained at a high level, correlating with increased serum triglycerides. Further, retro-orbital tissues from GC-resistant, very severe GO were shown to be infiltrated by CXCR3+ Th17 cells expressing Tbet and STAT4 and rich in triglycerides that promoted Th1 phenotype in Th17 cells in vitro.

CONCLUSIONS

Our findings address the importance of Th17.1 cells in GO pathogenesis, possibly promoting our understanding of the association between Th17-cell plasticity and disease severity of GO.

Expansion of the CD4+ effector T-cell repertoire characterizes peanut-allergic patients with heightened clinical sensitivity

BACKGROUND

Individuals with peanut allergy range in clinical sensitivity: some can consume grams of peanut before experiencing any symptoms, whereas others suffer systemic reactions to 10 mg or less. Current diagnostic testing only partially predicts this clinical heterogeneity.

OBJECTIVE

We sought to identify characteristics of the peanut-specific CD4+ T-cell response in peanut-allergic patients that correlate with high clinical sensitivity.

METHODS

We studied the T-cell receptor β-chain (TCRβ) usage and phenotypes of peanut-activated, CD154+ CD4+ memory T cells using fluorescence-activated cell sorting, TCRβ sequencing, and RNA-Seq, in reactive and hyporeactive patients who were stratified by clinical sensitivity.

RESULTS

TCRβ analysis of the CD154+ and CD154- fractions revealed more than 6000 complementarity determining region 3 sequences and motifs that were significantly enriched in the activated cells and 17% of the sequences were shared between peanut-allergic individuals, suggesting strong convergent selection of peanut-specific clones. These clones were more numerous among the reactive patients, and this expansion was identified within effector, but not regulatory T-cell populations. The transcriptional profile of CD154+ T cells in the reactive group skewed toward a polarized TH2 effector phenotype, and expression of TH2 cytokines strongly correlated with peanut-specific IgE levels. There were, however, also non-TH2-related differences in phenotype. Furthermore, the ratio of peanut-specific clones in the effector versus regulatory T-cell compartment, which distinguished the clinical groups, was independent of specific IgE concentration.

CONCLUSIONS

Expansion of the peanut-specific effector T-cell repertoire is correlated with clinical sensitivity, and this observation may be useful to inform our assessment of disease phenotype and to monitor disease longitudinally.

T follicular helper and memory cell responses and the mTOR pathway in murine heart transplantation

BACKGROUND

The mammalian target of rapamycin (mTOR) inhibitors are valuable immunosuppressants in clinical transplantation; however, the mTOR regulation of allogeneic T-cell responses is not fully understood yet. Therefore, the objective of this study is to investigate the effects of T-cell-specific mTOR deletion on the allogeneic T-cell responses and heart transplant survival.

METHODS

BALB/c heart allografts, with or without BALB/c skin sensitization, were transplanted in the wild-type C57BL/6, Mtor^fl/flCd4-Cre, Stat3^fl/flCd4-Cre, and Mtor^fl/flStat3^fl/flCd4-Cre mice. Graft survival and histology, as well as T-cell frequencies and phenotypes, were evaluated after transplantation.

RESULTS

In the absence of donor skin sensitization, long-term heart allograft survival was achieved in the Mtor^fl/flCd4-Cre recipients, which was associated with significantly decreased frequencies of CD62L^-CD44⁺ effector T cells and BCL-6⁺CXCR5⁺ T follicular helper (Tfh) cells in the periphery. Long-term heart allograft survival was also achieved in the donor skin-sensitized Mtor^fl/flStat3^fl/flCd4-Cre mice, whereas the heart allograft survival was prolonged in the donor skin-sensitized Mtor^fl/flCd4-Cre and Stat3^fl/flCd4-Cre mice.

CONCLUSIONS

mTOR is required for Tfh cell response in murine heart transplantation. T-cell-specific deletion of both mTOR and Stat3 abrogates the memory response to heart transplants. These findings help us to better understand the molecular mechanisms underlying the T cell immunity to transplanted organs.

Immunomodulatory Bonds of the Partnership between Dendritic Cells and T Cells

By acquiring, processing, and presenting both foreign and self-antigens, dendritic cells (DCs) initiate T cell activation that is shaped through the immunomodulatory functions of a variety of cell-membrane-bound molecules including BTLA-HVEM, CD40-CD40L, CTLA-4-CD80/CD86, CD70-CD27, ICOS-ICOS-L, OX40-OX40L, and PD-L1-PD-1, as well as several key cytokines and enzymes such as interleukin-6 (IL-6), IL-12, IL-23, IL-27, transforming growth factor-beta 1 (TGF-β1), retinaldehyde dehydrogenase (Raldh), and indoleamine 2,3-dioxygenase (IDO). Some of these distinct immunomodulatory signals are mediated by specific subsets of DCs, therefore contributing to the functional specialization of DCs in the priming and regulation of immune responses. In addition to responding to the DC-mediated signals, T cells can reciprocally modulate the immunomodulatory capacities of DCs, further refining immune responses. Here, we review recent studies, particularly in experimental mouse systems, that have delineated the integrated mechanisms of crucial immunomodulatory pathways that enable specific populations of DCs and T cells to work intimately together as single functional units that are indispensable for the maintenance of immune homeostasis.

Individual Effector/Regulator T Cell Ratios Impact Bone Regeneration

There is increasing evidence that T lymphocytes play a key role in controlling endogenous regeneration. Regeneration appears to be impaired in case of local accumulation of CD8+ effector T cells (T_EFF), impairing endogenous regeneration by increasing a primary “useful” inflammation toward a damaging level. Thus, rescuing regeneration by regulating the heightened pro-inflammatory reaction employing regulatory CD4+ T (T_Reg) cells could represent an immunomodulatory option to enhance healing. Hypothesis was that CD4+ T_Reg might counteract undesired effects of CD8+ T_EFF. Using adoptive T_Reg transfer, bone healing was consistently improved in mice possessing an inexperienced immune system with low amounts of CD8+ T_EFF. In contrast, mice with an experienced immune system (high amounts of CD8+ T_EFF) showed heterogeneous bone repair with regeneration being dependent upon the individual T_EFF/T_Reg ratio. Thus, the healing outcome can only be improved by an adoptive T_Reg therapy, if an unfavorable T_EFF/T_Reg ratio can be reshaped; if the individual CD8+ T_EFF percentage, which is dependent on the individual immune experience can be changed toward a favorable ratio by the T_Reg transfer. Remarkably, also in patients with impaired fracture healing the T_EFF/T_Reg ratio was higher compared to uneventful healers, validating our finding in the mouse osteotomy model. Our data demonstrate for the first time the key-role of a balanced T_EFF/T_Reg response following injury needed to reach successful regeneration using bone as a model system. Considering this strategy, novel opportunities for immunotherapy in patients, which are at risk for impaired healing by targeting T_EFF cells and supporting T_Reg cells to enhance healing are possible.

Staphylococcus aureus Lipoprotein Induces Skin Inflammation, Accompanied with IFN-γ-Producing T Cell Accumulation through Dermal Dendritic Cells

Staphylococcus aureus (S. aureus) is a commensal bacteria on the human skin, which causes serious skin inflammation. Several immune cells, especially effector T cells (Teff), have been identified as key players in S. aureus-derived skin inflammation. However, the bacterial component that induces dramatic host immune responses on the skin has not been well characterized. Here, we report that S. aureus lipoprotein (SA-LP) was recognized by the host immune system as a strong antigen, so this response induced severe skin inflammation. SA-LP activated dendritic cells (DCs), and this activation led to Teff accumulation on the inflamed skin in the murine intradermal (ID) injection model. The skin-accumulated Teff pool was established by IFN-ɤ-producing CD4⁺ and CD8⁺T (Th1 and Tc1). SA-LP activated dermal DC (DDC) in a dominant manner, so that these DCs were presumed to possess the strong responsibility of SA-LP-specific Teff generation in the skin-draining lymph nodes (dLN). SA-LP activated DC transfer into the mice ear, which showed similar inflammation, accompanied with Th1 and Tc1 accumulation on the skin. Thus, we revealed that SA-LP has a strong potential ability to establish skin inflammation through the DC-Teff axis. This finding provides novel insights not only for therapy, but also for the prevention of S. aureus-derived skin inflammation.

αEβ7 Integrin Identifies Subsets of Pro-Inflammatory Colonic CD4+ T Lymphocytes in Ulcerative Colitis

BACKGROUND AND AIMS

The αEβ7 integrin is crucial for retention of T lymphocytes at mucosal surfaces through its interaction with E-cadherin. Pathogenic or protective functions of these cells during human intestinal inflammation, such as ulcerative colitis [UC], have not previously been defined, with understanding largely derived from animal model data. Defining this phenotype in human samples is important for understanding UC pathogenesis and is of translational importance for therapeutic targeting of αEβ7-E-cadherin interactions.

METHODS

αEβ7+ and αEβ7- colonic T cell localization, inflammatory cytokine production and expression of regulatory T cell-associated markers were evaluated in cohorts of control subjects and patients with active UC by immunohistochemistry, flow cytometry and real-time PCR of FACS-purified cell populations.

RESULTS

CD4+αEβ7+ T lymphocytes from both healthy controls and UC patients had lower expression of regulatory T cell-associated genes, including FOXP3, IL-10, CTLA-4 and ICOS in comparison with CD4+αEβ7- T lymphocytes. In UC, CD4+αEβ7+ lymphocytes expressed higher levels of IFNγ and TNFα in comparison with CD4+αEβ7- lymphocytes. Additionally the CD4+αEβ7+ subset was enriched for Th17 cells and the recently described Th17/Th1 subset co-expressing both IL-17A and IFNγ, both of which were found at higher frequencies in UC compared to control.

CONCLUSION

αEβ7 integrin expression on human colonic CD4+ T cells was associated with increased production of pro-inflammatory Th1, Th17 and Th17/Th1 cytokines, with reduced expression of regulatory T cell-associated markers. These data suggest colonic CD4+αEβ7+ T cells are pro-inflammatory and may play a role in UC pathobiology.

Novel model of double transgenic mouse results in autoimmune diabetes in males

Identifying the type of diabetogenic CD8⁺ T cells that initiate autoimmune diabetes (AID) is a critical step in designing appropriate strategies for the early detection of beta cell-directed autoimmunity and its progression to diabetes. We generated a novel double transgenic (Tg) mouse model on the naturally diabetes resistant C57Bl/6 background, co-expressing two transgenes including a specific TCR anti-lymphocytic choriomeningitis virus nucleoprotein (LCMV-NP) carried by CD8⁺ T cells and LCMV-NP (as neo-self antigen) expressed by pancreatic beta cells. The resulting double Tg mouse showed partial thymic deletion of the NP-specific CD8⁺ T cells. The escaping autoreactive NP-specific CD8⁺ T cells joining the periphery were activated and gained effector functions. Both male and female mice mounted anti-NP antibodies, but only one-fourth adult males spontaneously developed AID. Significant upregulation of the CD44 and CD122 markers as compared to healthy male and female mice characterized the phenotype of diabetogenic CD8⁺ T cells in diabetic male mice. We also show that only 10% of these CD8⁺T cells expressed programmed death 1 receptor (PD-1). Together, these results suggest that in our double Tg mouse model, Ag-specific effector CD44⁺CD122⁺PD-1^-CD8⁺ T cell subpopulation is associated with the pathogenesis of AID.

High-dose wogonin exacerbates DSS-induced colitis by up-regulating effector T cell function and inhibiting Treg cell

Wogonin exerts anti‐tumour activities via multiple mechanisms. We have identified that high‐dose wogonin (50 or 100 mg/kg) could inhibit the growth of transplanted tumours by directly inducing tumour apoptosis and promoting DC, T and NK cell recruitment into tumour tissues to enhance immune surveillance. However, wogonin (20–50 μM) ex vivo prevents inflammation by inhibiting NF‐κB and Erk signalling of macrophages and epithelial cells. It is elusive whether high‐dose wogonin promotes or prevents inflammation. To investigate the effects of high‐dose wogonin on murine colitis induced by dextran sodium sulphate (DSS), mice were co‐treated with DSS and various doses of wogonin. Intraperitoneal administration of wogonin (100 mg/kg) exacerbated DSS‐induced murine colitis. More CD4⁺CD44⁺ and CD8⁺CD44⁺ cells were located in the inflamed colons in the wogonin (100 mg/kg) treatment group than in the other groups. Frequencies of CD4⁺CD25⁺CD127⁻ and CD4⁺CD25⁺ Foxp3⁺ cells in the colons and spleen respectively, were reduced by wogonin treatment. Ex vivo stimulations with high‐dose wogonin (50–100 μg/ml equivalent to 176–352 μM) could synergize with IL‐2 to promote the functions of CD4⁺ and CD8⁺ cells. However, regulatory T cell induction was inhibited. Wogonin stimulated the activation of NF‐κB and Erk but down‐regulated STAT3 phosphorylation in the CD4⁺ T cells. Wogonin down‐regulated Erk and STAT3‐Y705 phosphorylation in the regulatory T cells but promoted NF‐κB and STAT3‐S727 activation. Our study demonstrated that high‐dose wogonin treatments would enhance immune activity by stimulating the effector T cells and by down‐regulating regulatory T cells.

Regulation of chemo-sensitivity in ovarian cancer via a stroma dependent glutathione pathway

The primary chemotherapeutic agents for epithelial ovarian cancer are platinum-based drugs, which are commonly used in combination with a taxane regimen. These treatments are generally effective at achieving remission, but the remission is often followed by a relapse and acquired resistance to chemotherapy. In order to overcome these barriers of drug resistance, it is important to understand the underlying mechanisms regulating the development of drug-resistant tumors. Tumors evolve through interactions with the surrounding microenvironment, which are comprised of a complex mixture of cells including fibroblasts and immune cells. In ovarian cancer, fibroblasts can make up a significant component of the primary tumor. While fibroblasts are known to influence the behavior of cancer cells directly through secretion of growth factors, and extracellular matrix (ECM) proteins, the interactions between fibroblasts and immune cells are less understood. In a recently published study from Cell, Wang and colleagues present intriguing work characterizing the role of fibroblast and T cells in modulating platinum resistance in ovarian cancer. Here, we briefly summarize and comment on their findings in relation to the tumor microenvironment and chemoresistance.

Co-Stimulatory Blockade of the CD28/CD80-86/CTLA-4 Balance in Transplantation: Impact on Memory T Cells?

CD28 and CTLA-4 are prototypal co-stimulatory and co-inhibitory cell surface signaling molecules interacting with CD80/86, known to be critical for immune response initiation and regulation, respectively. Initial “bench-to-beside” translation, two decades ago, resulted in the development of CTLA4-Ig, a biologic that targets CD80/86 and prevents T-cell costimulation. In spite of its proven effectiveness in inhibiting allo-immune responses, particularly in murine models, clinical experience in kidney transplantation with belatacept (high-affinity CTLA4-Ig molecule) reveals a high incidence of acute, cell-mediated rejection. Originally, the etiology of belatacept-resistant graft rejection was thought to be heterologous immunity, i.e., the cross-reactivity of the pool of memory T cells from pathogen-specific immune responses with alloantigens. Recently, the standard view that memory T cells arise from effector cells after clonal contraction has been challenged by a “developmental” model, in which less differentiated memory T cells generate effector cells. This review delineates how this shift in paradigm, given the differences in co-stimulatory and co-inhibitory signal depending on the maturation stage, could profoundly affect our understanding of the CD28/CD80-86/CTLA-4 blockade and highlights the potential advantages of selectively targeting CD28, instead of CD80/86, to control post-transplant immune responses.

Inflammation, immunity, and hypertensive end-organ damage

For >50 years, it has been recognized that immunity contributes to hypertension. Recent data have defined an important role of T cells and various T cell-derived cytokines in several models of experimental hypertension. These studies have shown that stimuli like angiotensin II, deoxycorticosterone acetate-salt, and excessive catecholamines lead to formation of effector like T cells that infiltrate the kidney and perivascular regions of both large arteries and arterioles. There is also accumulation of monocyte/macrophages in these regions. Cytokines released from these cells, including interleukin-17, interferon-γ, tumor necrosis factorα, and interleukin-6 promote both renal and vascular dysfunction and damage, leading to enhanced sodium retention and increased systemic vascular resistance. The renal effects of these cytokines remain to be fully defined, but include enhanced formation of angiotensinogen, increased sodium reabsorption, and increased renal fibrosis. Recent experiments have defined a link between oxidative stress and immune activation in hypertension. These have shown that hypertension is associated with formation of reactive oxygen species in dendritic cells that lead to formation of gamma ketoaldehydes, or isoketals. These rapidly adduct to protein lysines and are presented by dendritic cells as neoantigens that activate T cells and promote hypertension. Thus, cells of both the innate and adaptive immune system contribute to end-organ damage and dysfunction in hypertension. Therapeutic interventions to reduce activation of these cells may prove beneficial in reducing end-organ damage and preventing consequences of hypertension, including myocardial infarction, heart failure, renal failure, and stroke.

Tissue specific heterogeneity in effector immune cell response

Post pathogen invasion, migration of effector T-cell subsets to specific tissue locations is of prime importance for generation of robust immune response. Effector T cells are imprinted with distinct “homing codes” (adhesion molecules and chemokine receptors) during activation which regulate their targeted trafficking to specific tissues. Internal cues in the lymph node microenvironment along with external stimuli from food (vitamin A) and sunlight (vitamin D₃) prime dendritic cells, imprinting them to play centre stage in the induction of tissue tropism in effector T cells. B cells as well, in a manner similar to effector T cells, exhibit tissue-tropic migration. In this review, we have focused on the factors regulating the generation and migration of effector T cells to various tissues along with giving an overview of tissue tropism in B cells.

Human effector T cells derived from central memory cells rather than CD8(+)T cells modified by tumor-specific TCR gene transfer possess superior traits for adoptive immunotherapy

Adoptive cell therapy provides an attractive treatment of cancer, and our expanding capacity to target tumor antigens is driven by genetically engineered human T lymphocytes that express genes encoding tumor-specific T cell receptors (TCRs). The intrinsic properties of cultured T cells used for therapy were reported to have tremendous influences on their persistence and antitumor efficacy in vivo. In this study, we isolated CD8(+) central memory T cells from peripheral blood lymphocytes of healthy donors, and then transferred with the gene encoding TCR specific for tumor antigen using recombinant adenovirus vector Ad5F35-TRAV-TRBV. We found effector T cells derived from central memory T cells improved cell viability, maintained certain level of CD62L expression, and reacquired the CD62L(+)CD44(high) phenotype of central memory T cells after effector T cells differentiation. We then compared the antitumor reactivity of central memory T cells and CD8(+)T cells after TCR gene transferred. The results indicated that tumor-specific TCR gene being transferred to central memory T cells effectively increased the specific killing of antigen positive tumor cells and the expression of cytolytic granule protein. Furthermore, TCR gene transferred central memory T cells were more effective than TCR gene transferred CD8(+)T cells in CTL activity and effector cytokine secretion. These results implicated that isolating central memory T cells rather than CD8(+)T cells for insertion of gene encoding tumor-specific TCR may provide a superior tumor-reactive T cell population for adoptive transfer.