The CD28 family: a T-cell rheostat for therapeutic control of T-cell activation

Systematic decoding of cis gene regulation defines context-dependent control of the multi-gene costimulatory receptor locus in human T cells

Cis-regulatory elements (CREs) interact with trans regulators to orchestrate gene expression, but how transcriptional regulation is coordinated in multi-gene loci has not been experimentally defined. We sought to characterize the CREs controlling dynamic expression of the adjacent costimulatory genes CD28, CTLA4 and ICOS, encoding regulators of T cell-mediated immunity. Tiling CRISPR interference (CRISPRi) screens in primary human T cells, both conventional and regulatory subsets, uncovered gene-, cell subset- and stimulation-specific CREs. Integration with CRISPR knockout screens and assay for transposase-accessible chromatin with sequencing (ATAC-seq) profiling identified trans regulators influencing chromatin states at specific CRISPRi-responsive elements to control costimulatory gene expression. We then discovered a critical CCCTC-binding factor (CTCF) boundary that reinforces CRE interaction with CTLA4 while also preventing promiscuous activation of CD28. By systematically mapping CREs and associated trans regulators directly in primary human T cell subsets, this work overcomes longstanding experimental limitations to decode context-dependent gene regulatory programs in a complex, multi-gene locus critical to immune homeostasis.

Involvement of expanded cytotoxic and proinflammatory CD28null T cells in primary Sjögren's syndrome

OBJECTIVE

The absence of CD28 is a feature of antigen-experienced, highly differentiated and aged T cells. The pathogenicity of CD28null T cells remains elusive in primary Sjögren's syndrome (pSS). Therefore, this study was performed to explore the characteristics of CD28null T cells in both peripheral blood and minor salivary glands (MSGs) of pSS patients.

METHODS

pSS patients and paired healthy controls (HCs) were enrolled. The phenotype of peripheral CD28null T cells was analyzed using flow cytometry. In vitro functional assays were performed to evaluate the cytotoxic and proinflammatory effects of peripheral CD28null T cells. In addition, polychromatic immunofluorescence staining was performed to investigate infiltrating CD28null T cells in MSGs.

RESULTS

A significant expansion of peripheral CD28null T cells was observed in pSS patients compared with HCs (p < 0.001), which were primarily CD8+CD28null T cells. The proportion of peripheral CD8+CD28null T cells moderately correlated with the erythrocyte sedimentation rate (r = 0.57, p < 0.01) and IgG levels (r = 0.44, p < 0.01). Peripheral CD28null T cells had stronger capacities to secrete granzyme B and perforin, but comparable capacities to secrete IFN-γ and TNF-α than their CD28+ counterparts. An abundant amount of cytotoxic and pro-inflammatory CD28null T cells was also found in MSGs. Moreover, a high expression of the chemokine receptor CXCR3 was found on peripheral and tissue-resident CD28null T cells, with its ligands CXCL9/10 abundantly present in MSGs.

CONCLUSION

Increasing CD28null T cells with strong cytotoxicity and proinflammatory effects were observed in both peripheral blood and MSGs from pSS patients. The precise mechanism of action and migration still needs further investigation.

An immune-related gene prognostic prediction risk model for neoadjuvant chemoradiotherapy in rectal cancer using artificial intelligence

Background

This study aimed to establish and validate a prognostic model based on immune-related genes (IRGPM) for predicting disease-free survival (DFS) in patients with locally advanced rectal cancer (LARC) undergoing neoadjuvant chemoradiotherapy, and to elucidate the immune profiles associated with different prognostic outcomes.

Methods

Transcriptomic and clinical data were sourced from the Gene Expression Omnibus (GEO) database and the West China Hospital database. We focused on genes from the RNA immune-oncology panel. The elastic net approach was employed to pinpoint immune-related genes significantly impacting DFS. We developed the IRGPM for rectal cancer using the random forest technique. Based on the IRGPM, we calculated prognostic risk scores to categorize patients into high-risk and low-risk groups. Comparative analysis of immune characteristics between these groups was conducted.

Results

In this study, 407 LARC samples were analyzed. The elastic net identified a signature of 20 immune-related genes, forming the basis of the IRGPM. Kaplan-Meier survival analysis revealed a lower 5-year DFS in the high-risk group compared to the low-risk group. The receiver operating characteristic (ROC) curve affirmed the model's robust predictive capability. Validation of the model was performed in the GSE190826 cohort and our institution's cohort. Gene expression differences between high-risk and low-risk groups predominantly related to cytokine-cytokine receptor interactions. Notably, the low-risk group exhibited higher immune scores. Further analysis indicated a greater presence of activated B cells, activated CD8 T cells, central memory CD8 T cells, macrophages, T follicular helper cells, and type 2 helper cells in the low-risk group. Additionally, immune checkpoint analysis revealed elevated PDCD1 expression in the low-risk group.

Conclusions

The IRGPM, developed through random forest and elastic net methodologies, demonstrates potential in distinguishing DFS among LARC patients receiving standard treatment. Notably, the low-risk group, as defined by the IRGPM, showed enhanced activation of adaptive immune responses within the tumor microenvironment.

Blocking Superantigen-Mediated Diseases: Challenges and Future Trends

Superantigens are virulence factors secreted by microorganisms that can cause various immune diseases, such as overactivating the immune system, resulting in cytokine storms, rheumatoid arthritis, and multiple sclerosis. Some studies have demonstrated that superantigens do not require intracellular processing and instated bind as intact proteins to the antigen-binding groove of major histocompatibility complex II on antigen-presenting cells, resulting in the activation of T cells with different T-cell receptor Vβ and subsequent overstimulation. To combat superantigen-mediated diseases, researchers have employed different approaches, such as antibodies and simulated peptides. However, due to the complex nature of superantigens, these approaches have not been entirely successful in achieving optimal therapeutic outcomes. CD28 interacts with members of the B7 molecule family to activate T cells. Its mimicking peptide has been suggested as a potential candidate to block superantigens, but it can lead to reduced T-cell activity while increasing the host's infection risk. Thus, this review focuses on the use of drug delivery methods to accurately target and block superantigens, while reducing the adverse effects associated with CD28 mimic peptides. We believe that this method has the potential to provide an effective and safe therapeutic strategy for superantigen-mediated diseases.

Peripheral immune responses to filoviruses in a reservoir versus spillover hosts reveal transcriptional correlates of disease

Several filoviruses, including Marburg virus (MARV), cause severe disease in humans and nonhuman primates (NHPs). However, the Egyptian rousette bat (ERB, Rousettus aegyptiacus), the only known MARV reservoir, shows no overt illness upon natural or experimental infection, which, like other bat hosts of zoonoses, is due to well-adapted, likely species-specific immune features. Despite advances in understanding reservoir immune responses to filoviruses, ERB peripheral blood responses to MARV and how they compare to those of diseased filovirus-infected spillover hosts remain ill-defined. We thus conducted a longitudinal analysis of ERB blood gene responses during acute MARV infection. These data were then contrasted with a compilation of published primate blood response studies to elucidate gene correlates of filovirus protection versus disease. Our work expands on previous findings in MARV-infected ERBs by supporting both host resistance and disease tolerance mechanisms, offers insight into the peripheral immunocellular repertoire during infection, and provides the most direct known cross-examination between reservoir and spillover hosts of the most prevalently-regulated response genes, pathways and activities associated with differences in filovirus pathogenesis and pathogenicity.

Chimeric Antigen Receptor T Cell Therapy in Acute Myeloid Leukemia: Trials and Tribulations

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy that is often associated with relapse and drug resistance after standard chemotherapy or targeted therapy, particularly in older patients. Hematopoietic stem cell transplants are looked upon as the ultimate salvage option with curative intent. Adoptive cell therapy using chimeric antigen receptors (CAR) has shown promise in B cell malignancies and is now being investigated in AML. Initial clinical trials have been disappointing in AML, and we review current strategies to improve efficacy for CAR approaches. The extensive number of clinical trials targeting different antigens likely reflects the genetic heterogeneity of AML. The limited number of patients reported in multiple early clinical studies makes it difficult to draw conclusions about CAR safety, but it does suggest that the efficacy of this approach in AML lags behind the success observed in B cell malignancies. There is a clear need not only to improve CAR design but also to identify targets in AML that show limited expression in normal myeloid lineage cells.

Considerations and Approaches for Cancer Immunotherapy in the Aging Host

Advances in cancer immunotherapy are improving treatment successes in many distinct cancer types. Nonetheless, most tumors fail to respond. Age is the biggest risk for most cancers, and the median population age is rising worldwide. Advancing age is associated with manifold alterations in immune cell types, abundance, and functions, rather than simple declines in these metrics, the consequences of which remain incompletely defined. Our understanding of the effects of host age on immunotherapy mechanisms, efficacy, and adverse events remains incomplete. A deeper understanding of age effects in all these areas is required. Most cancer immunotherapy preclinical studies examine young subjects and fail to assess age contributions, a remarkable deficit given the known importance of age effects on immune cells and factors mediating cancer immune surveillance and immunotherapy efficacy. Notably, some cancer immunotherapies are more effective in aged versus young hosts, while others fail despite efficacy in the young. Here, we review our current understanding of age effects on immunity and associated nonimmune cells, the tumor microenvironment, cancer immunotherapy, and related adverse effects. We highlight important knowledge gaps and suggest areas for deeper enquiries, including in cancer immune surveillance, treatment response, adverse event outcomes, and their mitigation.

B- and T-lymphocyte attenuator could be a new player in accelerated atherosclerosis associated with chronic kidney disease

BACKGROUND

In chronic kidney disease (CKD), cardiovascular morbi-mortality is higher than in general population. Atherosclerotic cardiovascular disease is accelerated in CKD, but specific CKD-related risk factors for atherosclerosis are unknown.

METHODS

CKD patients from the NEFRONA study were used. We performed mRNA array from blood of patients free from atheroma plaque at baseline, with (n=10) and without (n=10) de novo atherosclerotic plaque development 2 years later. Selected mRNA candidates were validated in a bigger sample (n=148). Validated candidates were investigated in vivo in an experimental model of CKD-accelerated atherosclerosis, and in vitro in murine macrophages.

RESULTS

mRNA array analysis showed 92 up-regulated and 67 down-regulated mRNAs in samples from CKD patients with de novo plaque development. The functional analysis pointed to a paramount role of the immune response. The validation in a bigger sample confirmed that B- and T-lymphocyte co-inhibitory molecule (BTLA) down-regulation was associated with de novo plaque presence after 2 years. However, BTLA down-regulation was not found to be associated with atherosclerotic progression in patients with plaque already present at baseline. In a model of CKD-accelerated atherosclerosis, mRNA and protein expression levels of BTLA were significantly decreased in blood samples and atheroma plaques. Plaques from animals with CKD were bigger, had more infiltration of inflammatory cells, higher expression of IL6 and IL17 and less presence of collagen than plaques from control animals. Incubation of macrophages with rat uremic serum decreased BTLA expression.

CONCLUSIONS

BTLA could be a potential biomarker or therapeutic target for atherosclerosis incidence in CKD patients.

The homodimer interfaces of costimulatory receptors B7 and CD28 control their engagement and pro-inflammatory signaling

BACKGROUND

The inflammatory response is indispensable for protective immunity, yet microbial pathogens often trigger an excessive response, 'cytokine storm', harmful to the host. Full T-cell activation requires interaction of costimulatory receptors B7-1(CD80) and B7-2(CD86) expressed on antigen-presenting cells with CD28 expressed on the T cells. We created short peptide mimetics of the homodimer interfaces of the B7 and CD28 receptors and examined their ability to attenuate B7/CD28 coligand engagement and signaling through CD28 for inflammatory cytokine induction in human immune cells, and to protect from lethal toxic shock in vivo.

METHODS

Short B7 and CD28 receptor dimer interface mimetic peptides were synthesized and tested for their ability to attenuate the inflammatory cytokine response of human peripheral blood mononuclear cells, as well as for their ability to attenuate B7/CD28 intercellular receptor engagement. Mice were used to test the ability of such peptides to protect from lethal superantigen toxin challenge when administered in molar doses far below the toxin dose.

RESULTS

B7 and CD28 homodimer interfaces are remote from the coligand binding sites, yet our finding is that by binding back into the receptor dimer interfaces, short dimer interface mimetic peptides inhibit intercellular B7-2/CD28 as well as the tighter B7-1/CD28 engagement, attenuating thereby pro-inflammatory signaling. B7 mimetic peptides exhibit tight selectivity for the cognate receptor in inhibiting intercellular receptor engagement with CD28, yet each diminishes signaling through CD28. In a prominent example of inflammatory cytokine storm, by attenuating formation of the B7/CD28 costimulatory axis, B7-1 and CD28 dimer interface mimetic peptides protect mice from lethal toxic shock induced by a bacterial superantigen even when administered in doses far submolar to the superantigen.

CONCLUSIONS

Our results reveal that the B7 and CD28 homodimer interfaces each control B7/CD28 costimulatory receptor engagement and highlight the protective potential against cytokine storm of attenuating, yet not ablating, pro-inflammatory signaling via these receptor domains.

Analysis of causes for poor persistence of CAR-T cell therapy in vivo

Chimeric antigen receptor T-cell (CAR-T-cell) therapy has been well researched to date because of its ability to target malignant tumor cells. The most common CAR-T cells are CD19 CAR-T cells, which play a large role in B-cell leukemia treatment. However, most CAR-T cells are associated with relapse after clinical treatment, so the quality and persistence of CAR-T cells need to be improved. With continuous optimization, there have been four generations of CARs and each generation of CARs has better quality and durability than the previous generation. In addition, it is important to increase the proportion of memory cells in CAR-T cells. Studies have shown that an immunosuppressive tumor microenvironment (TME) can lead to dysfunction of CAR-T cells, resulting in decreased cell proliferation and poor persistence. Thus, overcoming the challenges of immunosuppressive molecules and targeting cytokines in the TME can also improve CAR-T cell persistence. In this paper, we explored how to improve the durability of CAR-T cell therapy by improving the structure of CARs, increasing the proportion of memory CAR-T cells and improving the TME.

The effect of combining PD-1 agonist and low-dose Interleukin-2 on treating systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease involving multiple organs. It is often called "immortal cancer" due to the difficulties in disease treatment. As the cornerstone of immune regulation, the programmed cell death protein 1 (PD-1) has been extensively studied in the context of chronic inflammation due to its ability of regulating immune response and immunosuppression. Recently, more and more studies on rheumatic immune related complications have also focused on PD-1 and proposed that the use of PD-1 agonist could inhibit the activation of lymphocytes and alleviate SLE disease activity. In this review, we summarized the role of PD-1 in SLE, implicating its potential application as a biomarker to predict SLE disease activity; we also proposed that the combination of PD-1 agonist and low-dose IL-2 may have better therapeutic efficacy, shining light on a new direction for developing specific treatment approaches.

Common genetic variants associated with melanoma risk or naevus count in patients with wildtype MC1R melanoma

BACKGROUND

Hypomorphic MC1R variants are the most prevalent genetic determinants of melanoma risk in the white population. However, the genetic background of patients with wildtype (WT) MC1R melanoma is poorly studied.

OBJECTIVES

To analyse the role of candidate common genetic variants on the melanoma risk and naevus count in Spanish patients with WT MC1R melanoma.

METHODS

We examined 753 individuals with WT MC1R from Spain (497 patients and 256 controls). We used OpenArray reverse-transcriptase polymerase chain reaction to genotype a panel of 221 common genetic variants involved in melanoma, naevogenesis, hormonal pathways and proinflammatory pathways. Genetic models were tested using multivariate logistic regression models. Nonparametric multifactor dimensionality reduction (MDR) was used to detect gene-gene interactions within each biological subgroup of variants.

RESULTS

We found that variant rs12913832 in the HERC2 gene, which is associated with blue eye colour, increased melanoma risk in individuals with WT MC1R [odds ratio (OR) 1·97, 95% confidence interval (CI) 1·48-2·63; adjusted P < 0·001; corrected P < 0·001]. We also observed a trend between the rs3798577 variant in the oestrogen receptor alpha gene (ESR1) and a lower naevus count, which was restricted to female patients with WT MC1R (OR 0·51, 95% CI 0·33-0·79; adjusted P = 0·002; corrected P = 0·11). This sex-dependent association was statistically significant in a larger cohort of patients with melanoma regardless of their MC1R status (n = 1497; OR 0·71, 95% CI 0·57-0·88; adjusted P = 0·002), reinforcing the hypothesis of an association between hormonal pathways and susceptibility to melanocytic proliferation. Last, the MDR analysis revealed four genetic combinations associated with melanoma risk or naevus count in patients with WT MC1R.

CONCLUSIONS

Our data suggest that epistatic interaction among common variants related to melanocyte biology or proinflammatory pathways might influence melanocytic proliferation in individuals with WT MC1R. What is already known about this topic? Genetic variants in the MC1R gene are the most prevalent melanoma genetic risk factor in the white population. Still, 20-40% of cases of melanoma occur in individuals with wildtype MC1R. Multiple genetic variants have a pleiotropic effect in melanoma and naevogenesis. Additional variants in unexplored pathways might also have a role in melanocytic proliferation in these patients. Epidemiological evidence suggests an association of melanocytic proliferation with hormonal pathways and proinflammatory pathways. What does this study add? Variant rs12913832 in the HERC2 gene, which is associated with blue eye colour, increases the melanoma risk in individuals with wildtype MC1R. Variant rs3798577 in the oestrogen receptor gene is associated with naevus count regardless of the MC1R status in female patients with melanoma. We report epistatic interactions among common genetic variants with a role in modulating the risk of melanoma or the number of naevi in individuals with wildtype MC1R. What is the translational message? We report a potential role of hormonal signalling pathways in melanocytic proliferation, providing a basis for better understanding of sex-based differences observed at the epidemiological level. We show that gene-gene interactions among common genetic variants might be responsible for an increased risk for melanoma development in individuals with a low-risk phenotype, such as darkly pigmented hair and skin.

The Regulatory Effects of MicroRNAs on Tumor Immunity

MicroRNAs are endogenous noncoding small RNAs that posttranscriptionally regulate the expressions of their target genes. Accumulating research shows that miRNAs are crucial regulators of immune cell growth and antitumor immune response. Studies on miRNAs and tumors primarily focus on the tumor itself. At the same time, relatively few studies on the indirect regulatory effects of miRNAs in the development of tumors are achieved by affecting the immune system of tumor hosts and altering their immune responses. This review discusses the influence of miRNAs on the antitumor immune system.

Recent Advances in Solid Tumor CAR-T Cell Therapy: Driving Tumor Cells From Hero to Zero?

Chimeric antigen receptor T-cells (CAR-Ts) are known as revolutionary living drugs that have turned the tables of conventional cancer treatments in certain hematologic malignancies such as B-cell acute lymphoblastic leukemia (B-ALL) and diffuse large B-cell lymphoma (DLBCL) by achieving US Food and Drug Administration (FDA) approval based on their successful clinical outcomes. However, this type of therapy has not seen the light of victory in the fight against solid tumors because of various restricting caveats including heterogeneous tumor antigen expression and the immunosuppressive tumor microenvironments (TME) that negatively affect the tumor-site accessibility, infiltration, stimulation, activation, and persistence of CAR-Ts. In this review, we explore strategic twists including boosting vaccines and designing implementations that can support CAR-T expansion, proliferation, and tumoricidal capacity. We also step further by underscoring novel strategies for triggering endogenous antitumor responses and overcoming the limitation of poor CAR-T tumor-tissue infiltration and the lack of definitive tumor-specific antigens. Ultimately, we highlight how these approaches can address the mentioned arduous hurdles.

The CD8α-PILRα interaction maintains CD8+ T cell quiescence

T cell quiescence is essential for maintaining a broad repertoire against a large pool of diverse antigens from microbes and tumors, but the underlying molecular mechanisms remain largely unknown. We show here that CD8α is critical for the maintenance of CD8⁺ T cells in a physiologically quiescent state in peripheral lymphoid organs. Upon inducible deletion of CD8α, both naïve and memory CD8⁺ T cells spontaneously acquired activation phenotypes and subsequently died without exposure to specific antigens. PILRα was identified as a ligand for CD8α in both mice and humans, and disruption of this interaction was able to break CD8⁺ T cell quiescence. Thus, peripheral T cell pool size is actively maintained by the CD8α-PILRα interaction in the absence of antigen exposure.

Structural characterization of a dimerization interface in the CD28 transmembrane domain

CD28 has a crucial role in regulating immune responses by enhancing T cell activation and differentiation. Recent studies have shown that the transmembrane helix (TMH) of CD28 mediates receptor assembly and activity, but a structural characterization of TMH is still lacking. Here, we determined the dimeric helix-helix packing of CD28-TMH using nuclear magnetic resonance (NMR) technology. Unexpectedly, wild-type CD28-TMH alone forms stable tetramers in lipid bicelles instead of dimers. The NMR structure of the CD28-TMH C165F mutant reveals that a GxxxA motif, which is highly conserved in many dimeric assemblies, is located at the dimerization interface. Mutating G160 and A164 can disrupt the transmembrane helix assembly and reduces CD28 enhancement in cells. In contrast, a previously proposed YxxxxT motif does not affect the dimerization of full-length CD28, but it does affect CD28 activity. These results imply that the transmembrane domain of CD28 regulates the signaling transduction in a complicated manner.

Important roles of the human leukocyte antigen class I and II molecules and their associated genes in the autoimmune coagulation factor XIII deficiency via whole-exome sequencing analysis

Autoimmune coagulation factor XIII deficiency is a bleeding disorder caused by the formation of autoantibodies against the coagulation factor XIII (FXIII); however, the molecular mechanism underlying this process is unknown. Therefore, in the present study, we aimed to elucidate this mechanism by performing whole-exome sequencing analysis of 20 cases of autoimmune FXIII deficiency. We identified approximately 21,788–23,916 variants in each case. In addition to their ability to activate T cells, present antigens, and immune tolerance, the candidate alleles were further narrowed down according to their allelic frequencies and the magnitude of damage caused by the substitution of amino acids. After selecting 44 candidate alleles, we investigated whether they were associated with the FXIII inhibitory titers and/or the anti-FXIII autoantibodies. We found that two polymorphisms whose variant allele frequencies were significantly lower in the patients tended to decrease FXIII inhibitory titers as the number of variant alleles increased. We also found that five polymorphisms whose variant allele frequencies were significantly higher in the patients tended to increase the levels of the anti-FXIII autoantibodies as the number of variant alleles increased. All of these polymorphisms were found in the human leukocyte antigen (HLA) class I and II molecules and their associated genes. In particular, the HLA class II molecule and its associated genes were found to be involved in the presentation of foreign antigens as well as the negative regulation of the proliferation of T-cells and the release of cytokines. Polymorphisms in the HLA class II molecules and the cytotoxic T lymphocyte antigen 4 have been reported to be associated with the development of autoantibodies in acquired hemophilia A. Therefore, we hypothesized that these polymorphisms may be associated with the development of autoantibodies in autoimmune FXIII deficiency.

Markers of Follicular Helper T Cells Are Occasionally Expressed in T-Cell or Histiocyte-Rich Large B-Cell Lymphoma, Classic Hodgkin Lymphoma, and Atypical Paracortical HyperplasiaA Diagnostic Pitfall For T-Cell Lymphomas of T Follicular Helper Origin

OBJECTIVES

Follicular helper T cell (TFH) markers are expressed in angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma of the TFH phenotype (PTCL-TFH). However, differential expression and coexpression of these markers in benign and other malignant lymphoid proliferations have not been well studied.

METHODS

We performed programmed death-1 (PD-1), C-X-C motif chemokine ligand 13 (CXCL13), inducible costimulator (ICOS), CD10, and B-cell lymphoma 6 protein (BCL-6) immunohistochemistry on AITL, PTCL not otherwise specified (PTCL-NOS), PTCL-TFH, T-cell or histiocyte-rich large B-cell lymphoma (THRLBCL), classic Hodgkin lymphoma (CHL), atypical paracortical hyperplasia (PCH), progressive transformation of germinal centers (PTGC), and reactive follicular hyperplasia (RFH).

RESULTS

CXCL13 and ICOS were more sensitive but less specific for AITL than PD-1, CD10, and BCL-6. Moreover, 74% of AITL (none of PTCL-NOS or PTCL-TFH) coexpressed more than 2 TFH markers. In background T cells of THRLBCL, 70% of cases coexpressed more than 1 marker. The background T cells of CHL expressed all TFH markers except CD10 in all cases. In addition, 13% of PCH cases coexpressed more than 1 marker. In RFH and PTGC, all markers were expressed mainly in germinal centers with rare extrafollicular staining.

CONCLUSIONS

AITL, PTCL-NOS, and PTCL-TFH show differential expression of TFH markers. AITL frequently coexpresses more than 2 TFH markers. TFH markers can be expressed in PCH and in background T cells of THRLBCL and CHL. Consequently, caution should be used before a diagnosis of AITL is established, particularly with limited samples.

[Expression of integrins β1, α4 and cell adhesion molecule ICAM-1 in the presence of sodium deoxyribonucleate with ferrum complex (DNA-Na-Fe) by MT-4 cells transformed by human T-lymphotropic virus type 1 (Retroviridae: Orthoretrovirinae: Deltaretrovirus: Human T-lymphotropic virus type 1)]

INTRODUCTION

The important role of integrins (IG) in the initiation and development of cancer processes makes these structures convenient targets for the development of immunomodulatory therapeutic drugs that have an effect directly on these molecules. Among the latter, IG β1, α4 and cell adhesion receptor ICAM-1 (intercellular adhesion molecule 1) are of particular interest. Immunomodulators are capable of changing the IG activity through non-specific mechanisms, which, however, in some cases can cause a decrease in the protective functions of the immune system and health deterioration.The aim of the study was to determine the effect on the levels of cellular expression and the nature of IG metabolism of the drug sodium deoxyribonucleate with ferrum complex, DNA-Na-Fe, which is having been used in the Russian Federation as an immunomodulatory agent, but whose action has not been studied in details so far.

MATERIAL AND METHODS

We used 2 variants of the neoplastic CD4+ T-lymphocyte cell line transformed with human T-lymphotropic virus type 1 (HTLV-1) of the Retroviridae family, MT-4 (MT-4/1 and MT-4/2). The indicated variants were characterized by different levels of expression of the protein activation markers CD28 and CD38. After cell culture in the presence of 500 μg/ml DNA-Na-Fe, the expression levels of IG β1 (CD29), α4 (CD49d), and ICAM-1 (CD54) were studied by flow cytometry.

RESULTS

The cells of the both lines contained many membrane proteins CD29+ (90.4% ± 4.5) and CD54+ (97.9% ± 1.4), while small percentage of cells contained protein CD49d+ (1.9% ± 1.0). No changes in the expression of the studied proteins were observed in the presence of the drug.

DISCUSSION

The levels of IG β1, α4 and ICAM-1 expression may serve as one of the phenotypic characteristics of MT-4 cells. The obtained data are of great importance because the peculiarities of CD4+ T-lymphocytes transformation and their metabolism during HTLV-1 infection have not been sufficiently studied so far.

CONCLUSION

The results of this work may be helpful in determining the pathogenesis of HTLV-1-induced diseases, some types of malignancies, and in searching for new specific pharmacological agents, including molecularly targeted ones. The results of the study will help to expand the existing knowledge on the markers of MT-4 cell line.

Oleuropin controls miR-194/XIST/PD-L1 loop in triple negative breast cancer: New role of nutri-epigenetics in immune-oncology

Oleuropein, the main secoiridoid glucoside found in Olea europaea L., has attracted scientific community as a potential anticancer agent. Immunotherapy and RNA interference revolutionized cancer treatment. Success of PD-L1/PD-1 antibodies encouraged the investigation of PD-1/PD-L1 regulation by non-coding RNAs. This study aimed to verify the cytotoxic effect of oleuropein on MDA-MB-231 cell line and to unravel novel ceRNA interaction between miR-194-5p and XIST in breast cancer and their immunomodulatory effect on PD-L1 expression to propose a promising prophylactic and preventive role of Oleuropin in diet. For the first time, miR-194/Lnc-RNA XIST/PD-L1 triad was investigated in breast cancer, where miR-194 and PD-L1 levels were significantly upregulated in 21 BC-biopsies, yet XIST was downregulated. Ectopic expression of miR-194 enhanced cell function and viability with concomitant increase in PD-L1 expression yet XIST expression decreased, in contrast to miR-194 antagomirs that yielded opposite results. XIST knock-out elevated miR194-5p and PD-L1 levels. miR-194-5p mimics and XIST siRNAs co-transfection induced PD-L1 expression, while miR-194-5p mimics and TSIX siRNAs co-transfection showed opposite effect. Oleuropein showed anti-carcinogenic impact by decreasing miR-194 and PD-L1 levels while increasing XIST level. In conclusion, our study highlighted novel ceRNA interaction controlling PD-L1 expression in BC. Oleuropein is a promising nutraceutical for cancer therapy. Therefore, oleuropin represents a new nutri-epigenetic in immune-oncology that controls miR-194/XIST/PD-L1 loop in triple negative breast cancer.

Chromosome 2q33genetic polymorphisms in Tunisian endemic pemphigus foliaceus

Background

Several studies have suggested that polymorphisms within genes encoding T‐lymphocyte immune regulating molecules: CD28, CTLA‐4, and ICOS, may alter the signaling process and subsequently could be involved in susceptibility to a broad spectrum of autoimmune diseases.

Methods

This study aimed to replicate associations between common polymorphisms in the 2q33.2 cluster and susceptibility to pemphigus foliaceus (PF) in the Tunisian population. We investigated seven polymorphisms: rs3116496 and rs1879877 (CD28), rs231775, rs3087243, and (AT)_n repeat (CTLA4); rs11889031 and rs10932029 (ICOS) in a case–control study which enrolled 106 Tunisian PF patients and 205 matched healthy controls.

Results

We confirmed the associations with CTLA4((AT)₁₃, p = 0.00137, OR = 3.96 and (AT)₂₀, p = 0.008, OR = 5.22; respectively) and ICOS genes (rs10932029>CT, p = 0.034, OR = 2.12 and rs10932029>TT, p = 0.04 and OR = 0.41).

Conclusion

Our results indicate that susceptibility to PF is located in the proximal and the distal 3′ flanking region of the CTLA4/ICOS promoter. These findings may open avenues to the treatment of patients with biological drugs targeting CTLA4/ICOS molecules, in a personalized manner to achieve more effective treatment.

The CD28 Transmembrane Domain Contains an Essential Dimerization Motif

CD28 plays a critical role in regulating immune responses both by enhancing effector T cell activation and differentiation and controlling the development and function of regulatory T cells. CD28 is expressed at the cell surface as a disulfide linked homodimer that is thought to bind ligand monovalently. How ligand binding triggers CD28 to induce intracellular signaling as well as the proximal signaling pathways that are induced are not well-understood. In addition, recent data suggest inside-out signaling initiated by the T cell antigen receptor can enhance CD28 ligand binding, possibly by inducing a rearrangement of the CD28 dimer interface to allow for bivalent binding. To understand how possible conformational changes during ligand-induced receptor triggering and inside-out signaling are mediated, we examined the CD28 transmembrane domain. We identified an evolutionarily conserved YxxxxT motif that is shared with CTLA-4 and resembles the transmembrane dimerization motif within CD3ζ. We show that the CD28 transmembrane domain can drive protein dimerization in a bacterial expression system at levels equivalent to the well-known glycophorin A transmembrane dimerization motif. In addition, ectopic expression of the CD28 transmembrane domain into monomeric human CD25 can drive dimerization in murine T cells as detected by an increase in FRET by flow cytometry. Mutation of the polar YxxxxT motif to hydrophobic leucine residues (Y145L/T150L) attenuated CD28 transmembrane mediated dimerization in both the bacterial and mammalian assays. Introduction of the Y145L/T150L mutation of the CD28 transmembrane dimerization motif into the endogenous CD28 locus by CRISPR resulted in a dramatic loss in CD28 cell surface expression. These data suggest that under physiological conditions the YxxxxT dimerization motif within the CD28 transmembrane domain plays a critical role in the assembly and/or expression of stable CD28 dimers at the cell surface.

HIV-Resistant and HIV-Specific CAR-Modified CD4+ T Cells Mitigate HIV Disease Progression and Confer CD4+ T Cell Help In Vivo

HIV infection preferentially depletes HIV-specific CD4+ T cells, thereby impairing antiviral immunity. In this study, we explored the therapeutic utility of adoptively transferred CD4+ T cells expressing an HIV-specific chimeric antigen receptor (CAR4) to restore CD4+ T cell function to the global HIV-specific immune response. We demonstrated that CAR4 T cells directly suppressed in vitro HIV replication and eliminated virus-infected cells. Notably, CAR4 T cells containing intracellular domains (ICDs) derived from the CD28 receptor family (ICOS and CD28) exhibited superior effector functions compared to the tumor necrosis factor receptor (TNFR) family ICDs (CD27, OX40, and 4-1BB). However, despite demonstrating limited in vitro efficacy, only HIV-resistant CAR4 T cells expressing the 4-1BBζ ICD exhibited profound expansion, concomitant with reduced rebound viremia after antiretroviral therapy (ART) cessation and protection of CD4+ T cells (CAR-) from HIV-induced depletion in humanized mice. Moreover, CAR4 T cells enhanced the in vivo persistence and efficacy of HIV-specific CAR-modified CD8+ T cells expressing the CD28ζ ICD, which alone exhibited poor survival. Collectively, these studies demonstrate that HIV-resistant CAR4 T cells can directly control HIV replication and augment the virus-specific CD8+ T cell response, highlighting the therapeutic potential of engineered CD4+ T cells to engender a functional HIV cure.

Engineering Cytoplasmic Signaling of CD28ζ CARs for Improved Therapeutic Functions

Chimeric antigen receptor modified T cells (CAR-T) have yielded impressive clinical outcomes in treating hematopoietic malignancies. However, relapses have occurred in a substantial number of patients and limited the development of CAR-T therapy. Most underlying reasons for these relapses can be attributed to poor persistence and rapid exhaustion of CAR-T cells in vivo. Despite multiple strategies having been developed, how to improve CAR-T persistence or resist exhaustion while maintaining sufficient cytotoxic functions is still a great challenge. Here we discuss engineering cytoplasmic signaling as an important strategy for CAR optimization. This review summarizes recent advances showing that the anti-tumor function of CAR-T cells can be improved by optimizing the CD3ζ domain or downstream signaling of CD28ζ CAR.

Recombinant Costimulatory Fusion Proteins as Functional Immunomodulators Enhance Antitumor Activity in Murine B16F10 Melanoma

Blocking inhibitory signaling and engaging stimulatory signaling have emerged as important therapeutic modalities for cancer immunotherapy. This study aimed to investigate immunomodulatory features of three recombinant costimulatory ligand proteins in a mouse model, which are extracellular domains of OX40-ligand (OX40L), 4-1BB-ligand (4-1BBL), or two domains in tandem, fused with the transmembrane domain of diphtheria toxin (DTT), named DTT-COS1, DTT-COS2, and DTT-COS12, respectively. In vitro study showed that DTT-COS1 and DTT-COS12 had immunological activity increasing the ratio of CD8/CD4 T cells. Treatments with DTT-COS1 and DTT-COS12 dramatically generated immune protection against the B16F10 tumor challenge in both prophylactic and therapeutic efficacy. Furthermore, regarding tumor microenvironment (TME) immunomodulation, DTT-COS1 treatment increased the proportion of CD4+ effector T cells (Teff) and decreased the expression of a suppressive cytokine. Meanwhile, DTT-COS12 reduced regulatory T cells (Treg) and improved the level of stimulatory cytokines. In addition, endogenous antibodies against OX40L/4-1BBL were generated, which may help with antitumor responses. Unexpectedly, DTT-COS2 lacked antitumor effects in vitro and in vivo. Importantly, serum analysis of liver-function associated factors and pro-inflammatory cytokines demonstrated that treatments were safe formulations in mice without signs of systemic toxicity. Remarkably, DTT-COS1 and DTT-COS12 are functional immunomodulators for mouse B16F10 melanoma, creating practical preclinical value in cancer immunotherapy.

High numbers of differentiated CD28null CD8+ T cells are associated with a lowered risk for late rejection and graft loss after kidney transplantation

Background

The hypothesis was tested that parameters of an aged T-cell compartment associate with the risk for late rejection after kidney transplantation.

Methods

Recipients of a kidney transplant in the period 2007–2013 were (N = 365) were included. T cells were characterized prior to transplantation by flow cytometry as naive (CD45RO^-CCR7⁺), central-memory (CD45RO⁺CCR7⁺), effector-memory (CD45RO^-CCR7^-) or terminally differentiated CD8⁺ Temra (CD45RO^-/CCR7^-/CD28^-) cells. T cell telomere length and thymic output were assessed prior to transplantation in 202 recipients. Follow-up was until December 2018. The date of the first time of biopsy-proven late rejection (>6 months after transplantation) was used to calculate the rejection-free survival time.

Results

Fifty cases of biopsy-proven rejection were recorded. Thymic output and T cell telomere length did not associate with late rejection-free survival. However, the percentage and absolute numbers of CD8⁺Temra and CD28null CD8⁺ T cells were significantly lower in patients with late rejection. Specifically, in the highest tertile of percentages of CD28null CD8⁺ T cells, the cumulative incidence of late rejection at 5 and 10 years was only 5% and 8% compared to 16% and 20% in the middle to lowest tertile (p = 0.002). Multivariate proportional hazard analysis showed that percentage and absolute number of CD28null CD8⁺ T cells remained significantly associated with late rejection and rejection-related graft loss.

Conclusion

High numbers of differentiated CD28null CD8⁺ T cells decrease the risk for late rejection and rejection-related graft loss after kidney transplantation.

A randomized, phase 1b study of the pharmacokinetics, pharmacodynamics, safety, and tolerability of bleselumab, a fully human, anti-CD40 monoclonal antibody, in kidney transplantation

This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of various doses of the anti-CD40 monoclonal antibody bleselumab (ASKP1240) in de novo kidney transplant recipients receiving concomitant standard immunosuppression over 90 days posttransplant. Transplant recipients were randomized (1:1:1:1:1) to bleselumab 50 mg, 100 mg, 200 mg, or 500 mg, or placebo, in addition to standard maintenance immunosuppression. The primary pharmacokinetic endpoints were AUC_inf , C_max , and AUC_last . The primary pharmacodynamic endpoint was B cell CD40 receptor occupancy over time. Overall, 50 kidney transplant recipients were randomized; 45 received their randomized treatment (bleselumab [n = 37] or placebo [n = 8]). AUC_inf and AUC_last demonstrated a more than dose-proportional increase in the range of 50-500 mg, and C_max increased linearly with increasing dose. Maximal receptor occupancy for B cell CD40 was reached at all dose levels and was prolonged as dose increased. No kidney transplant recipients experienced cytokine release syndrome or a thromboembolic event. Treatment-emergent anti-bleselumab antibodies were found in one kidney transplant recipient in the bleselumab 50 mg group; these were detected only at Day 7. Overall, bleselumab demonstrated nonlinear pharmacokinetics and dose-dependent prolonged B cell CD40 receptor occupancy and was well tolerated at all doses (ClinicalTrials.gov: NCT01279538).

Teleost cytotoxic T cells

Cell-mediated cytotoxicity is one of the major mechanisms by which vertebrates control intracellular pathogens. Two cell types are the main players in this immune response, natural killer (NK) cells and cytotoxic T lymphocytes (CTL). While NK cells recognize altered target cells in a relatively unspecific manner CTLs use their T cell receptor to identify pathogen-specific peptides that are presented by major histocompatibility (MHC) class I molecules on the surface of infected cells. However, several other signals are needed to regulate cell-mediated cytotoxicity involving a complex network of cytokine- and ligand-receptor interactions. Since the first description of MHC class I molecules in teleosts during the early 90s of the last century a remarkable amount of information on teleost immune responses has been published. The corresponding studies describe teleost cells and molecules that are involved in CTL responses of higher vertebrates. These studies are backed by functional investigations on the killing activity of CTLs in a few teleost species. The present knowledge on teleost CTLs still leaves considerable room for further investigations on the mechanisms by which CTLs act. Nevertheless the information on teleost CTLs and their regulation might already be useful for the control of fish diseases by designing efficient vaccines against such diseases where CTL responses are known to be decisive for the elimination of the corresponding pathogen. This review summarizes the present knowledge on CTL regulation and functions in teleosts. In a special chapter, the role of CTLs in vaccination is discussed.

A significant association of the CTLA4 gene variants with the risk of autoimmune Graves' disease in ethnic Kashmiri population

Graves' disease (GD) is the commonest cause of hyperthyroidism in populations with adequate iodine intake. It results from an abnormality in the immune system, which produces unique antibodies causing over production of thyroid hormones and glandular hyperplasia in individuals with genetic susceptibility. The Cytotoxic Lymphocyte Associated Antigen-4 (CTLA4) gene product serves the important function of immunomodulation, thereby helping in maintenance of peripheral self-tolerance. Studies on the association of the CTLA4 SNPs with GD have shown variations in the results from different populations. Since no such study has been carried out in ethnic Kashmiri population, we aimed to study a possible association of the CTLA4 SNPs (+49 A/G, -318C/T, CT 60 A/G and -1661 A/G) with GD. A total of 285 individuals (135 patients with GD and 150 healthy individuals) were genotyped using PCR-RFLP method and the results showed statistically significant differences in genotypic and allelic frequencies of cases and controls for + 49 A/G SNP (p=<0.001; OR = 5.14; CI = 2.17-12.19) and CT 60 A/G SNP (p = < 0.001; OR = 6.9; CI = 2.8-16.6), while -318C/T and -1661 A/G SNPs showed no significant association. We also studied the mRNA expression of the CTLA4 in patients with GD and healthy individuals by Real-Time PCR and found a decreased expression of the CTLA4 mRNA in PBMCs of patients with GD as compared to healthy controls with a -3.71-fold change. We conclude that the CTLA4 + 49 A/G and CT 60 A/G SNPs have a significant association with the risk of GD development in Kashmiri population and CTLA4 mRNA expression is significantly decreased in GD.

Microglial Drug Targets in AD: Opportunities and Challenges in Drug Discovery and Development

Alzheimer’s disease (AD) is a large and increasing unmet medical need with no disease-modifying treatment currently available. Genetic evidence from genome-wide association studies (GWASs) and gene network analysis has clearly revealed a key role of the innate immune system in the brain, of which microglia are the most important element. Single-nucleotide polymorphisms (SNPs) in genes predominantly expressed in microglia have been associated with altered risk of developing AD. Furthermore, microglia-specific pathways are affected on the messenger RNA (mRNA) expression level in post-mortem AD tissue and in mouse models of AD. Together these findings have increased the interest in microglia biology, and numerous scientific reports have proposed microglial molecules and pathways as drug targets for AD. Target identification and validation are generally the first steps in drug discovery. Both target validation and drug lead identification for central nervous system (CNS) targets and diseases entail additional significant obstacles compared to peripheral targets and diseases. This makes CNS drug discovery, even with well-validated targets, challenging. In this article, we will illustrate the special challenges of AD drug discovery by discussing the viability/practicality of possible microglia drug targets including cluster of differentiation 33 (CD33), K_Ca3.1, kynurenines, ionotropic P2 receptor 7 (P2X7), programmed death-1 (PD-1), Toll-like receptors (TLRs), and triggering receptor expressed in myeloid cells 2 (TREM2).

Role of CTLA4 A49G polymorphism in systemic lupus erythematosus and its geographical distribution

CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) or CD152 is an inhibitory receptor expressed constitutively on CD4+ CD25+ T regulatory lymphocytes and transiently on activated CD4+ and CD8+ T lymphocytes. Its inhibitory function promotes long-lived anergy in immune cells and prevents autoimmunity. Therefore, it plays a crucial role in T cell-mediated autoimmunity, and thus in susceptibility to autoimmune diseases, including systemic lupus erythematosus (SLE). It is encoded by CTLA4 gene in humans. AtoG polymorphism at position +49 of CTLA4 gene is the only polymorphism which changes amino acid sequence from alanine to threonine in the leader sequence, which may affect the function of CTLA-4. Association of CTLA4 polymorphisms with SLE has been investigated in several reports in different ethnic populations from different countries, which have shown highly inconsistent findings. In this review, we have compiled previous studies which have reported the association of CTLA4 A49G polymorphism in SLE and its geographical distribution.

Striking a Balance-Cellular and Molecular Drivers of Memory T Cell Development and Responses to Chronic Stimulation

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.

Immune inhibitory proteins and their pathogenic and therapeutic implications in autoimmunity and autoimmune hepatitis

Key inhibitory proteins can blunt immune responses to self-antigens, and deficiencies in this repertoire may promote autoimmunity. The goals of this review are to describe the key immune inhibitory proteins, indicate their possible impact on the development of autoimmune disease, especially autoimmune hepatitis, and encourage studies to clarify their pathogenic role and candidacy as therapeutic targets. English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Cytotoxic T lymphocyte antigen-4 impairs ligation of CD28 to B7 ligands on antigen presenting cells and inhibits the adaptive immune response by increasing anti-inflammatory cytokines, generating regulatory T cells, and reducing T cell activation and proliferation. Programed cell death antigen-1 inhibits T cell selection, activation, and proliferation by binding with two ligands at different phases and locations of the immune response. A soluble alternatively spliced variant of this protein can dampen the inhibitory signal. Autoimmune hepatitis has been associated with polymorphisms of the cytotoxic T lymphocyte antigen-4 gene, reduced hepatic expression of a ligand of programed cell death antigen-1, an interfering soluble variant of this key inhibitory protein, and antibodies against it. Findings have been associated with laboratory indices of liver injury and suboptimal treatment response. Abatacept, belatacept, CD28 blockade, and induction of T cell exhaustion are management considerations that require scrutiny. In conclusion, deficiencies in key immune inhibitory proteins may promote the occurrence of autoimmune diseases, such as autoimmune hepatitis, and emerging interventions may overcome these deficiencies. Investigations should define the nature, impact and management of these inhibitory disturbances in autoimmune hepatitis.

Staphylococcal and Streptococcal Superantigens Trigger B7/CD28 Costimulatory Receptor Engagement to Hyperinduce Inflammatory Cytokines

Staphylococcal and streptococcal superantigens are virulence factors that cause toxic shock by hyperinducing inflammatory cytokines. Effective T-cell activation requires interaction between the principal costimulatory receptor CD28 and its two coligands, B7-1 (CD80) and B7-2 (CD86). To elicit an inflammatory cytokine storm, bacterial superantigens must bind directly into the homodimer interfaces of CD28 and B7-2. Recent evidence revealed that by engaging CD28 and B7-2 directly at their dimer interface, staphylococcal enterotoxin B (SEB) potently enhances intercellular synapse formation mediated by B7-2 and CD28, resulting in T-cell hyperactivation. Here, we addressed the question, whether diverse bacterial superantigens share the property of triggering B7-2/CD28 receptor engagement and if so, whether they are capable of enhancing also the interaction between B7-1 and CD28, which occurs with an order-of-magnitude higher affinity. To this end, we compared the ability of distinct staphylococcal and streptococcal superantigens to enhance intercellular B7-2/CD28 engagement. Each of these diverse superantigens promoted B7-2/CD28 engagement to a comparable extent. Moreover, they were capable of triggering the intercellular B7-1/CD28 interaction, analyzed by flow cytometry of co-cultured cell populations transfected separately to express human CD28 or B7-1. Streptococcal mitogenic exotoxin Z (SMEZ), the most potent superantigen known, was as sensitive as SEB, SEA and toxic shock syndrome toxin-1 (TSST-1) to inhibition of inflammatory cytokine induction by CD28 and B7-2 dimer interface mimetic peptides. Thus, superantigens act not only by mediating unconventional interaction between MHC-II molecule and T-cell receptor but especially, by strongly promoting engagement of CD28 by its B7-2 and B7-1 coligands, a critical immune checkpoint, forcing the principal costimulatory axis to signal excessively. Our results show that the diverse superantigens use a common mechanism to subvert the inflammatory response, strongly enhancing B7-1/CD28 and B7-2/CD28 costimulatory receptor engagement.

Endocrine Toxicity of Cancer Immunotherapy Targeting Immune Checkpoints

Immune checkpoints are small molecules expressed by immune cells that play critical roles in maintaining immune homeostasis. Targeting the immune checkpoints cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) with inhibitory antibodies has demonstrated effective and durable antitumor activity in subgroups of patients with cancer. The US Food and Drug Administration has approved several immune checkpoint inhibitors (ICPis) for the treatment of a broad spectrum of malignancies. Endocrinopathies have emerged as one of the most common immune-related adverse events (irAEs) of ICPi therapy. Hypophysitis, thyroid dysfunction, insulin-deficient diabetes mellitus, and primary adrenal insufficiency have been reported as irAEs due to ICPi therapy. Hypophysitis is particularly associated with anti-CTLA-4 therapy, whereas thyroid dysfunction is particularly associated with anti-PD-1 therapy. Diabetes mellitus and primary adrenal insufficiency are rare endocrine toxicities associated with ICPi therapy but can be life-threatening if not promptly recognized and treated. Notably, combination anti-CTLA-4 and anti-PD-1 therapy is associated with the highest incidence of ICPi-related endocrinopathies. The precise mechanisms underlying these endocrine irAEs remain to be elucidated. Most ICPi-related endocrinopathies occur within 12 weeks after the initiation of ICPi therapy, but several have been reported to develop several months to years after ICPi initiation. Some ICPi-related endocrinopathies may resolve spontaneously, but others, such as central adrenal insufficiency and primary hypothyroidism, appear to be persistent in most cases. The mainstay of management of ICPi-related endocrinopathies is hormone replacement and symptom control. Further studies are needed to determine (i) whether high-dose corticosteroids in the treatment of ICPi-related endocrinopathies preserves endocrine function (especially in hypophysitis), and (ii) whether the development of ICPi-related endocrinopathies correlates with tumor response to ICPi therapy.

Bacterial Superantigen Toxins, CD28, and Drug Development

During severe bacterial infections, death and disease are often caused by an overly strong immune response of the human host. Acute toxic shock is induced by superantigen toxins, a diverse set of proteins secreted by Gram-positive staphylococcal and streptococcal bacterial strains that overstimulate the inflammatory response by orders of magnitude. The need to protect from superantigen toxins led to our discovery that in addition to the well-known MHC class II and T cell receptors, the principal costimulatory receptor, CD28, and its constitutively expressed coligand, B7-2 (CD86), previously thought to have only costimulatory function, are actually critical superantigen receptors. Binding of the superantigen into the homodimer interfaces of these costimulatory receptors greatly enhances B7-2/CD28 engagement, leading to excessive pro-inflammatory signaling. This finding led to the design of short receptor dimer interface mimetic peptides that block the binding of superantigen and thus protect from death. It then turned out that such a peptide will protect also from Gram-negative bacterial infection and from polymicrobial sepsis. One such CD28 mimetic peptide is advancing in a Phase 3 clinical trial to protect from lethal wound infections by flesh-eating bacteria. These host-oriented therapeutics target the human immune system itself, rendering pathogens less likely to become resistant.

On the Road to Immunotherapy-Prospects for Treating Head and Neck Cancers With Checkpoint Inhibitor Antibodies

Head and neck cancers (HNC) represent a heterogeneous cluster of aggressive malignancies that account for 3% of all cancer cases in the UK. HNC is increasing in frequency particularly in the developing world, which is related to changes in risk factors. Unfortunately, the mortality rate is high, which is chiefly attributed to late diagnosis at stages where traditional treatments fail. Cancer immunotherapy has achieved great successes in anti-tumor therapy. Checkpoint inhibitor (CI) antibodies enhance anti-tumor activity by blocking inhibitory receptors to drive tumor-specific T and NK cell effector responses. Since their introduction in 2011, CI antibodies have been approved for many cancer types including HNC. Here, we examine the development of CI therapies and look forward to future developments for treatment of HNC with CI therapies.

Enhanced IL-6/phosphorylated STAT3 signaling is related to the imbalance of circulating T follicular helper/T follicular regulatory cells in patients with rheumatoid arthritis

Background

Follicular helper T (Tfh) cells are specialized in helping B lymphocytes, which play a central role in autoimmune diseases that have a major B cell component, such as in rheumatoid arthritis (RA). Follicular regulatory T (Tfr) cells control the over-activation of Tfh and B cells in germinal centers. Dysregulation of Tfh cells and Tfr cells has been reported to be involved in the pathogenesis of some autoimmune diseases. However, the balance of Tfh and Tfr cells, and their roles in the development and progression of RA are still not clear.

Methods

In this study, we enrolled 44 patients with RA (20 patients with active RA and 24 patients with inactive RA) and 20 healthy controls, and analyzed the frequencies of circulating Tfh and Tfr cells, expression of programmed death-1 (PD-1), inducible co-stimulator (ICOS), intracellular IL-21, and pSTAT3 in Tfh cells, and serum levels of IL-6. The correlation among these parameters and that of Tfh or Tfr cells with disease activity were also analyzed.

Results

Patients with RA (especially active RA) had higher frequencies of Tfh cells, but lower percentages of Tfr cells, thereby resulting in elevated ratios of Tfh/Tfr. Expression levels of PD-1 and IL-21 in Tfh cells were higher in patients with RA than in healthy subjects, while no difference in ICOS expression was observed between patients and controls. Both pSTAT3 expression and serum IL-6 levels increased in patients with RA, and positive correlation between them was observed. Additionally, pSTAT3 expression was positively correlated with Tfh cell frequency. The Disease Activity Score in 28 joints based on C-reactive protein (DAS28-CRP) was negatively correlated with Tfr cell frequency, but was positively correlated with both Tfh/Tfr ratio and PD-1 expression.

Conclusions

Results demonstrated that enhanced IL-6/pSTAT3 signaling may contribute to promotion of Tfh cells, consequently skewing the ratio of Tfh to Tfr cells, which may be crucial for disease progression in RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1690-0) contains supplementary material, which is available to authorized users.

Regulation of cancer immune escape: The roles of miRNAs in immune checkpoint proteins

Immune checkpoint proteins (ICPs) are regulators of immune system. The ICP dysregulation silences the host immune response to cancer-specific antigens, contributing to the occurrence and progress of various cancers. MiRNAs are regulatory molecules and function in mRNA silencing and post-transcriptional regulation of gene expression. MiRNAs that modulate the immunity via ICPs have received increasing attention. Many studies have shown that the expressions of ICPs are directly or indirectly repressed by miRNAs in multiple types of cancers. MiRNAs are also subject to regulation by ICPs. In this review, recent studies of the relationship between miRNAs and ICPs (including the PD-1, PD-L1, CTLA-4, ICOS, B7-1, B7-2, B7-H2, B7-H3, CD27, CD70, CD40, and CD40L) in cancer immune escape are comprehensively discussed, which provide critical detailed mechanistic insights into the functions of the miRNA-ICP axes and their effects on immune escape, and will be beneficial for the potential applications of immune checkpoint therapy and miRNA-based guidance for personalized medicine as well as for predicting the prognosis.

The shortening telomere length of T lymphocytes maybe associated with hyper‑function in servere aplastic anemia

Severe aplastic anemia (SAA) is a primary disorder of severe bone marrow failure characterizing with extreme pancytopenia and a profound diminution of bone marrow progenitor cells, which is associated with T cell hyper‑function. Abnormal telomere shortening of bone marrow mononuclear cell has been reported in AA, which may lead to genomic instability, and result in cell senescence or apoptosis. Notably, certain studies identfieid that lymphocytes of shortening telomere length have undergone apoptosis escape in autoimmune diseases. In order to investigate the association between telomere lengths and function of T lymphocytes in SAA, the relative telomere lengths (RTLs) of different subtypes of T lymphocytes were investigated by flow‑fluorescent in situ hybridization in 30 patients with SAA and 25 healthy controls. Then the levels of expression of cluster of differentiation 28 (CD28), CD158 and CD70 were measured, which represent the function of T lymphocytes. The apoptosis rate and the cell cycle progression of CD8+T lymphocytes, and the level of secretion interferon‑γ and tumor necrosis factor‑α were also measured. Finally, the correlation between telomere length and these functional events of CD8+T lymphocytes was analyzed in patients with SAA. The results showed that RTLs of CD8+T lymphocytes in SAA were significantly shorter compared with those in controls. Furthermore, in patients with SAA, CD8+T lymphocytes are associated with T cell hyper‑function, which is related to the RTL. Thus, the shorter RTLs of CD8+T lymphocytes in SAA may be associated with hyper‑function of these cells, which contribute to the pathogenesis of SAA.

Distinct patterns of infiltrating CD8+ T cells in HPV+ and CD68 macrophages in HPV- oropharyngeal squamous cell carcinomas are associated with better clinical outcome but PD-L1 expression is not prognostic

Immunotherapies are beginning to revolutionise treatment paradigms in oncology with monoclonal antibodies (mAb) targeting T-cell co-inhibitory (e.g. PD-1/PD-L1) and co-stimulatory pathways (e.g. CTLA-4/CD28) demonstrating clinical utility. Some clinical studies demonstrate that responsiveness to PD-1/PD-L1 mAb therapy is greater in patients with expression of PD-L1 in the tumour microenvironment. However, robust responses have also been observed in patients with low or absent expression of PD-L1. Using multiplex immuno-fluorescent labelling we sought to determine how infiltration of tumours by CD8⁺ T-cells, their expression of PD-1, and the expression of PD-L1 on both tumours and CD68 cells (macrophages) correlated with HPV status and outcome in a cohort of 124 oropharyngeal squamous cell carcinomas (OPSCC).

CTLA-4-expression on VZV-specific T cells in CSF and blood is specifically increased in patients with VZV related central nervous system infections

VZV-reactivation may lead to symptomatic central nervous system (CNS) diseases, but identification of VZV as causative pathogen of CNS-diseases is challenging. This study was performed to characterize VZV-specific T cells from cerebrospinal fluid (CSF) and blood of patients with active CNS-disease and to determine whether this may improve differential diagnosis. 27 patients with pleocytosis in the CSF were recruited and classified into three groups (10 VZV-related, 10 non-VZV-related, 7 unclear). VZV-specific CD4⁺ T cells were quantified in CSF and blood after simultaneous stimulation with a VZV-antigen lysate and detection of cytokines (IFN-γ, IL-2, TNF-α) and CTLA-4. Polyclonal stimulation served as positive control. VZV-specific CD4⁺ T-cell frequencies were highest in both CSF (p = 0.0001) and blood (p = 0.011) of patients with VZV-infection, and were enriched at the site of infection (p = 0.002). While cytokine-expression profiles only showed minor differences between the groups, CTLA-4-expression levels on VZV-specific T cells from CSF and blood were significantly increased in VZV-related CNS-infections (p = 0.0002 and p<0.0001) and clearly identified VZV-related CNS-diseases (100% sensitivity and 100% specificity). Polyclonally stimulated T cells did not show any quantitative and phenotypical differences between the groups. Increased frequency and CTLA-4-expression of VZV-specific T cells from CSF or blood are specifically found in patients with VZV-related CNS-infection.

Correlation analysis of the HLA-DPB1*05:01 and BTNL2 genes within the histocompatibility complex region with a clinical phenotype of psoriasis vulgaris in the Chinese Han population

BACKGROUND

The human major histocompatibility complex (MHC) is known to be highly polymorphic and has been identified to be associated with numerous diseases. The HLA-DPB1 and BTNL2 genes were associated with psoriasis for the first time. The present study aims to investigate the relevance of the HLA-DPB1 and BTNL2 genes with respect to clinical phenotypes of psoriasis vulgaris (PV).

METHODS

To investigate whether the HLA-DPB1 and BTNL2 polymorphisms were associated with clinical phenotypes of PV in Chinese Han population, we conducted an analysis in case-controls and case-only subjects (9906 controls and 8744 cases) via MHC targeted sequencing stratified analysis.

RESULTS

In cases and controls, analysis showed that the genotype of HLA-DPB1*05:01 was associated with type of guttate [p = 3.914 × 10^-2 , odds ratio (OR = 0.9335)] and northern region (p = 1.182 × 10^-3 , OR = 0.9108). In the case-only analysis, the genotype of HLA-DPB1*05:01 was significantly correlated with geographical region (p = 1.36 × 10^-3 , OR = 1.134). In cases and controls, analysis showed that the genotype of BTNL2 (rs 41355746) was associated with being male (p = 2.563 × 10^-2 , OR = 0.8897), early-onset (p = 9.399 × 10^-3 , OR = 0.8856), guttate (p = 2.469 × 10^-2 , OR = 0.8558) and family history (p = 1.51 × 10^-4 , OR = 0.772). In the case-only analysis, the genotype of BTNL2 (rs41355746) was significantly correlated with family history (p = 1.768 × 10^-3 , OR = 0.757) and age of onset (p = 3.818 × 10^-2 , OR = 1.195).

CONCLUSIONS

The results of the present study indicate that the HLA-DPB1*05:01 gene was associated with the geographical region of PV and the BTNL2 gene was significantly associated with family history and age of onset of PV. In conclusion, the HLA-DPB1*05:01 and BTNL2 genes might be responsible for the complicacy of clinical features.

Chimeric PD-1:28 Receptor Upgrades Low-Avidity T cells and Restores Effector Function of Tumor-Infiltrating Lymphocytes for Adoptive Cell Therapy

Inherent intermediate- to low-affinity T-cell receptors (TCR) that develop during the natural course of immune responses may not allow sufficient activation for tumor elimination, making the majority of T cells suboptimal for adoptive T-cell therapy (ATT). TCR affinity enhancement has been implemented to provide stronger T-cell activity but carries the risk of creating undesired cross-reactivity leading to potential serious adverse effects in clinical application. We demonstrate here that engineering of low-avidity T cells recognizing a naturally processed and presented tumor-associated antigen with a chimeric PD-1:28 receptor increases effector function to levels seen with high-avidity T cells of identical specificity. Upgrading the function of low-avidity T cells without changing the TCR affinity will allow a large arsenal of low-avidity T cells previously thought to be therapeutically inefficient to be considered for ATT. PD-1:28 engineering reinstated Th1 function in tumor-infiltrating lymphocytes that had been functionally disabled in the human renal cell carcinoma environment without unleashing undesired Th2 cytokines or IL10. Involved mechanisms may be correlated to restoration of ERK and AKT signaling pathways. In mouse tumor models of ATT, PD-1:28 engineering enabled low-avidity T cells to proliferate stronger and prevented PD-L1 upregulation and Th2 polarization in the tumor milieu. Engineered T cells combined with checkpoint blockade secreted significantly more IFNγ compared with T cells without PD-1:28, suggesting a beneficial combination with checkpoint blockade therapy or other therapeutic strategies. Altogether, the supportive effects of PD-1:28 engineering on T-cell function make it an attractive tool for ATT. Cancer Res; 77(13); 3577-90. ©2017 AACR.

IL-21 restricts T follicular regulatory T cell proliferation through Bcl-6 mediated inhibition of responsiveness to IL-2

T follicular regulatory (Tfr) cells control the magnitude and specificity of the germinal centre reaction, but how regulation is contained to ensure generation of high-affinity antibody is unknown. Here we show that this balance is maintained by the reciprocal influence of interleukin (IL)-2 and IL-21. The number of IL-2-dependent FoxP3+ regulatory T cells is increased in the peripheral blood of human patients with loss-of-function mutations in the IL-21 receptor (IL-21R). In mice, IL-21:IL-21R interactions influence the phenotype of T follicular cells, reducing the expression of CXCR4 and inhibiting the expansion of Tfr cells after T-cell-dependent immunization. The negative effect of IL-21 on Tfr cells in mice is cell intrinsic and associated with decreased expression of the high affinity IL-2 receptor (CD25). Bcl-6, expressed in abundance in Tfr cells, inhibits CD25 expression and IL-21-mediated inhibition of CD25 is Bcl-6 dependent. These findings identify a mechanism by which IL-21 reinforces humoral immunity by restricting Tfr cell proliferation.

Loss of CD28 within CD4+ T cell subsets from cervical cancer patients is accompanied by the acquisition of intracellular perforin, and is further enhanced by NKG2D expression

CD28 is well characterized as an essential co-stimulatory receptor critical for activation, proliferation and survival processes in CD4⁺ T cells. Populations of CD4⁺CD28^null T cells, with apparently contradictory physiological roles, have recently been reported, along with the co-expression of the NK activating receptor NKG2D, in autoimmune diseases and chronic viral inflammation. Paradoxically, studies in cancer suggest that an expanded CD4⁺NKG2D⁺ population may be armed with immunosuppressive properties. We have recently reported the existence of two separate CD4⁺NKG2D⁺ T cell populations, which were defined by the presence or absence of the co-stimulatory molecule CD28, with the CD4⁺CD28^nullNKG2D⁺ population more frequently observed in women with cervical cancer. This has led to the present effort to further characterize this population and to determine if the loss of CD28 influences the acquisition of cytotoxic or regulatory markers. In the present work, a multicolor flow cytometry protocol was used to analyze the expression of cytotoxic and immunoregulatory markers on circulating CD4⁺ T cells characterized by the presence or absence of CD28 and NKG2D in patients with invasive cervical carcinoma and age/gender-matched healthy controls. A noticeable expansion of CD4⁺CD28^null cells, many of them NKG2D⁺, were observed in selected cervical cancer samples. This CD4⁺CD28^null T cell population was characterized by a lack of immunoregulatory markers, as well as very low basal levels of intracellular IFN-γ, TNF-α, TGF-β, and IL-10. Intracellular perforin, however, was found to be significantly increased in this CD4⁺CD28^null population, and increases in the mean fluorescence intensity of perforin were found to be enhanced by the presence of NKG2D. In conclusion, our data provide the first evidence of a strict link between the absence of CD28 and the expression of perforin, which is likewise enhanced by the expression of NKG2D, within selected CD4⁺ T cells from cervical cancer patients.