In silico prediction of CD8+ and CD4+ T cell epitopes in Leishmania major proteome: Using immunoinformatics

The leishmaniases are NDTs (neglected tropical diseases) that affect people all over the world. They are brought on by protozoans from the genus Leishmania and disseminated by phlebotomine flies that are afflicted with the disease. The best option to manage and lower the incidence of these diseases has been thought by the creation of a safe and effective vaccination. This research used an in silico based mining approach to look for high potential epitopes that might bind to MHC Class I and MHC Class II molecules (mainly; HLA-A*02:01 & HLA-DRB1*03:01) from human population in order to promote vaccine development. Based on the presence of signal peptides, GPI anchors, antigenicity predictions, and a subtractive proteomic technique, we have screened 17 putative antigenic proteins from the 8083 total proteins of L. major. After that thorough immunogenic epitope prediction were done using IEDB-AR tools. We isolated five immunogenic epitopes (three 9-mer & two 15-mer) from five antigenic proteins through docking and MD simulation analysis. Finally, these five anticipated epitopes, viz., TLPEIPVNV, ELMAPVFGL, TLAAAVALL, NSINIRLDGVTSAGF and NVPLVVDASSLFRVA have considerably stronger binding potential with their respective alleles and may trigger immunological responses. The goal of this work was to identify MHC restricted epitopes for CD8+ and CD4+ T cells activation using immunoinformatics in order to identify potential vaccine candidates against L. major parasites.

EFHD2 regulates T cell receptor signaling and modulates T helper cell activation in early sepsis

EFHD2 (EF-hand domain family, member D2) has been identified as a calcium-binding protein with immunomodulatory effects. In this study, we characterized the phenotype of Efhd2-deficient mice in sepsis and examined the biological functions of EFHD2 in peripheral T cell activation and T helper (Th) cell differentiation. Increased levels of EFHD2 expression accompanied peripheral CD4+ T cell activation in the early stages of sepsis. Transcriptomic analysis indicated that immune response activation was impaired in Efhd2-deficient CD4+ T cells. Further, Efhd2-deficient CD4+ T cells isolated from the spleen of septic mice showed impaired T cell receptor (TCR)-induced Th differentiation, especially Th1 and Th17 differentiation. In vitro data also showed that Efhd2-deficient CD4+ T cells exhibit impaired Th1 and Th17 differentiation. In the CD4+ T cells and macrophages co-culture model for antigen presentation, the deficiency of Efhd2 in CD4+ T cells resulted in impaired formation of immunological synapses. In addition, Efhd2-deficient CD4+ T cells exhibited reduced levels of phospho-LCK and phospho-ZAP70, and downstream transcription factors including Nfat, Nfκb and Nur77 following TCR engagement. In summary, EFHD2 may promote TCR-mediated T cell activation subsequent Th1 and Th17 differentiation in the early stages of sepsis by regulating the intensity of TCR complex formation.

Regulation and impact of tumor-specific CD4+ T cells in cancer and immunotherapy

CD4+ T cells are crucial in generating and sustaining immune responses. They orchestrate and fine-tune mammalian innate and adaptive immunity through cell-based interactions and the release of cytokines. The role of these cells in contributing to the efficacy of antitumor immunity and immunotherapy has just started to be uncovered. Yet, many aspects of the CD4+ T cell response are still unclear, including the differentiation pathways controlling such cells during cancer progression, the external signals that program them, and how the combination of these factors direct ensuing immune responses or immune-restorative therapies. In this review, we focus on recent advances in understanding CD4+ T cell regulation during cancer progression and the importance of CD4+ T cells in immunotherapies.

Ectopic CD4+ T cells in choroid plexus mediate neuropsychiatric lupus symptoms in mice via interferon-γ induced microglia activation

Neuropsychiatric systemic lupus erythematosus (NPSLE) is a disabling and potentially life-threatening complication of SLE. This study aims to investigate whether ectopic CD4+ T cells in the choroid plexus mediate NPSLE in mice. Intracerebroventricular (ICV) injection of anti-CD4 antibody effectively depleted CP-resident CD4+ T cells and alleviated NPSLE-like symptoms in MRL/lpr mice. Following ICV injection, the majority of isolated lupus CD4+ T cells from donor MRL/lpr mice predominantly stayed in the CP for at least 28 days in recipient C57BL/6 mice, while nearly all isolated CD4+ T cells from MRL/MpJ mice disappeared within 7 days. ICV injection of lupus CD4+ T cells resulted in NPSLE-like symptoms, including impaired behavioral performances, increased microglial activation, and abnormal microstructure changes. Flow cytometry analysis revealed that the majority of isolated lupus CD4+ T cells were positive for IFN-γ. Neutralizing intracerebral IFN-γ alleviated NPSLE-like symptoms in MRL/lpr mice. Moreover, ICV injection of anti-IFN-γ antibody or microglial depletion by PLX3397 benefited most NPSLE-like symptoms in lupus CD4+ T-treated mice, while ICV injection of IFN-γ mimicked most NPSLE-like symptoms. In conclusion, CP-resident lupus CD4+ T cells contribute to NPSLE-like symptoms in mice via Interferon-γ induced microglia activation. Depleting CP-resident lupus CD4+ T cells, interferon-γ, or activated microglia may be potential therapeutic targets for NPSLE.

Costimulatory Molecule CD226 Regulates Atopic Dermatitis in a Mouse Model

This study investigated the role of CD226 in a 2,4-dinitrochlorobenzene (DNCB)-induced mouse model of atopic dermatitis. The results showed that the lack of CD226 (global and CD4+ T-cell specific) significantly increased ear thickness, reddening, swelling, and scaling of the skin as well as inflammatory cell and mast cell infiltration. RT-qPCR results demonstrated that the mRNA expressions of atopic dermatitis-related inflammatory cytokines and chemokines were markedly increased in the draining lymph nodes and lesioned ear skin tissues of global and CD4+ T-cell-specific CD226-deficient mice compared with that in control mice. In vitro assessment revealed that CD226 directly modulates TGFβ-mediated regulatory T (Treg) cell differentiation and proliferation. Notably, Treg cell-specific deletion of CD226 (Cd226fl/flFoxp3cre mice) resulted in more severe dermatitis and epidermal thickening than those observed in littermate mice upon DNCB treatment. Subsequent analysis showed that the infiltration of Treg cells in ear lesions and the number of Tregs in the spleen were significantly reduced in Cd226fl/flFoxp3cre mice after DNCB treatment. In addition, the lack of CD226 induced apoptosis of Treg cells through the activation of caspase 3. Therefore, these results suggest that CD226 has potential efficacy in atopic dermatitis, correlating with Treg cell inhibition.

The HLA-II immunopeptidome of SARS-CoV-2

Targeted synthetic vaccines have the potential to transform our response to viral outbreaks, yet the design of these vaccines requires a comprehensive knowledge of viral immunogens. Here, we report severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) peptides that are naturally processed and loaded onto human leukocyte antigen-II (HLA-II) complexes in infected cells. We identify over 500 unique viral peptides from canonical proteins as well as from overlapping internal open reading frames. Most HLA-II peptides colocalize with known CD4+ T cell epitopes in coronavirus disease 2019 patients, including 2 reported immunodominant regions in the SARS-CoV-2 membrane protein. Overall, our analyses show that HLA-I and HLA-II pathways target distinct viral proteins, with the structural proteins accounting for most of the HLA-II peptidome and nonstructural and noncanonical proteins accounting for the majority of the HLA-I peptidome. These findings highlight the need for a vaccine design that incorporates multiple viral elements harboring CD4+ and CD8+ T cell epitopes to maximize vaccine effectiveness.

NKG2D receptor regulates CD4+T cell differentiation via interaction with dendritic cells in patients with juvenile idiopathic arthritis

NKG2D provides a costimulatory signal for activation of CD4+ T cells. We explored its role in interactions of CD4+ T cells and dendritic cells (DCs) in juvenile idiopathic arthritis (JIA) patients by using NKG2D genetically modified CD4+ T cells. We found active JIA patients had significantly higher content of CD4 + NKG2D+ T cells than healthy controls. Expression of NKG2D on CD4+ T cells, and MICA and MICB on DCs were significantly greater in articular JIA than systemic JIA. NKG2D induced IL- 12 and suppressed IL-10 and TGF-β from CD4+ T cells, increased IFN-γ + CD4+ T and IL-17+ CD4+ T cells, RORc and T-bet, but reduced CD25+ Foxp3+ CD4+ T cells, IL-4+ CD4+ T cells, Foxp3, and GATA3 in JIA patients. NKG2D decreased IL-10 and increased CD83, MICA, and MICB of DCs in JIA and controls. So NKG2D regulates differentiation of CD4+ T cells directly and the maturation of DCs indirectly.

The effect of the BK polyomavirus large T antigen on the function and maturity of the CD4+ T cell subsets in kidney transplant recipients

BACKGROUND

In kidney transplant recipients (KTRs) who are immunosuppressed, human BK polyomavirus (BKPyV) infection can be reactivated, resulting in BKPyV-associated nephropathy (BKPyVN). Considering that BKPyV inhibits CD4+ T cell differentiation, we investigated the effect of BKPyV large T antigen (LT-Ag) on the maturation of CD4+ T cell subsets during active BKPyV infection.

METHODS

In this cross-sectional study, we examined the following groups: 1) five KTRs with active viral infection (BKPyV+ KTRs), 2) five KTRs without active viral infection (BKPyV-KTRs), and 3) five healthy controls. We measured the frequency of CD4+ T cells and their different subsets, such as naive T cells, central memory T cells (Tcm), and effector memory T cells (Tem). All these subsets were analyzed by flow cytometry in peripheral blood mononuclear cells (PBMCs) stimulated with the overlapping BKPyV LT-Ag peptide pool. In addition, CD4+ T cell subsets were analyzed by flow cytometry for the presence of CD4, CCR7, CD45RO, CD107a, and granzyme B (GB). In addition, mRNA expression of transcription factors (TFs) such as T-bet, GATA-3, STAT-3, and STAT-6 was examined. The probability of inflammation with perforin protein was examined by SYBR Green real-time PCR.

RESULTS

After stimulation of PBMCs, naive T cells (CD4+CCR7+CD45RO-) (p = 0.9) and CD4+ T cells which release CD107a+ (CD4+CD107a+Geranzyme B-) (p = 0.9) T cells were more abundant in BKPyV+ KTRs than in BKPyV- KTRs. In contrast, central memory T cells (CD4+CCR7+CD45RO+) (p = 0.1) and effector memory T cells (CD4+CCR7-CD45RO+) (p = 0.1) were more abundant in BKPyV- KTRs than in BKPyV+ KTRs. The mRNA expression levels of T-bet, GATA-3, STAT-3, and STAT-6 were significantly higher (p < 0.05) in BKPyV- KTRs than in BKPyV+ KTRs which may be due to a higher differentiation level of CD4+ T cells. Due to inflammation, the mRNA expression level of perforin was higher in BKPyV+ KTRs, than in BKPyV- KTRs, but the difference was not significant (p = 0.175).

CONCLUSIONS

The high number of naive T cells after PBMC stimulation with the LT-Ag peptide pool was observed in BKPyV+ KTRs due to the interaction of LT-Ag with T cells. This means that BKPyV by using its LT-Ag can inhibit the naive T cell differentiation to other T cell subsets like central and effector memory T cells. However, the frequency of CD4+ T cell subsets and the combination of the activities of these cells with the expression profile of the target genes in this study may be efficient in treating and diagnosing BKPyV infections in kidney recipients.

The relationship between CD4+ T cell glycolysis and their functions

CD4⁺ T cells are effector T cells (Teffs) produced by the differentiation of initial T cells in peripheral lymphoid tissue after being attacked by antigens, and have an indispensable role in the development and activation of B cells and CD8⁺ T cells to regulate and assist immunity. In this review, we provide a new perspective on the relationship between CD4⁺ T cell glycolysis and its function. We summarize the effects of changes in the glycolysis level of CD4⁺ T cells on their activation, differentiation, proliferation, and survival. In addition, we emphasize that regulation of the glycolysis level of CD4⁺ T cells changes their inflammatory phenotypes and function. The study of immune metabolism has received more attention recently, but more work is needed to answer many open questions.

T cells in ocular autoimmune uveitis: Pathways and therapeutic approaches

Autoimmune uveitis is a non-infectious intraocular condition that affects the uveal tract of the eye and threatens vision if not treated properly. Increasing evidence suggests that activated CD4⁺ T cells are associated with progressive and permanent destruction of photoreceptors in ocular autoimmune diseases. As such, the purpose of this review is to offer an overview of the role of CD4⁺ T cells in autoimmune uveitis as well as a justification for the current development and assessment of innovative autoimmune uveitis medications targeting CD4⁺ T cells. With an emphasis on T helper (Th)17, Th1, and Th2 cells, follicular helper CD4⁺ T cells, and regulatory T cells, this review presents a summary of recent research related to the pathways and signaling that encourage CD4⁺ T cells to develop into specialized effector cells. We also describe immunotherapeutic approaches based on CD4⁺ T cell subsets and their potential as therapeutic agents for autoimmune disorders.

Alleviating experimental allergic eye disease by inhibiting pro-lymphangiogenic VEGFR3 signal

PURPOSE

Ocular allergy leads to acute and chronic inflammation that may deteriorate the conjunctiva and other ocular tissue. The conjunctiva is covered with abundant lymphatic vessels but how the conjunctival lymphatic system patriciates in the development of allergic eye disease (AED) remains to be elucidated.

METHODS AND RESULTS

By using ovalbumin (OVA)+pertussis toxin (PTX) as a sensitizer followed by daily OVA challenges, we induced optimized AED manifestations in mice. We show that conjunctival lymphatics underwent significant expansion after 28 days of chronic OVA challenge, and this process can be prevented by inducible genetic ablation of lymphatic Vegfr3. Through transcriptomic profile analysis in combination with histopathological examinations, we found that pro-lymphangiogenic VEGFR3 signal promoted allergy-induced activation of T helper 2 (Th2) type immune responses, including antigen presentation, and Th2 cells, B cells and mast cell-related pathways in the conjunctiva, thereby critically contributing to the immunoglobulin E (IgE) production and AED manifestations. As a result, ocular allergy can be alleviated by genetic inhibition of lymphatic Vegfr3. Interestingly, pro-lymphangiogenic VEGFR3 signal did not appear to affect the obstruction of meibomian glands (MGs) or the activation of Th17 type and neutrophil pathways that are associated with AED.

CONCLUSIONS

These data reveal the key role of pro-lymphangiogenic VEGFR3 signaling in the development of AED and provide experimental evidence that VEGFR3 inhibition may be useful in treating ocular allergy in patients.

KLF10 deficiency in CD4+ T cells promotes atherosclerosis progression by altering macrophage dynamics

BACKGROUND AND AIMS

Accumulating evidence supports a critical role for CD4⁺ T cells as drivers and modifiers of the chronic inflammatory response in atherosclerosis. Effector T cells have pro-atherogenic properties, whereas CD4⁺ regulatory T cells (Tregs) exert suppressive activity in atherosclerosis through increased secretion of inhibitory cytokines such as transforming growth factor-β or interleukin-10. In addition, Tregs have been shown to suppress inflammatory macrophages and promote the resolution of atherosclerosis plaques. Impaired Treg numbers and function have been associated with atherosclerosis plaque development. However, the underlying mechanisms remain unclear.

METHODS AND RESULTS

Here, we investigated a cell-autonomous role of a transcription factor, Krüppel-like factor 10 (KLF10), in CD4⁺ T cells in regulating atherosclerosis progression. Using CD4⁺ T-cell-specific KLF10 knockout (TKO) mice, we identified exaggerated plaque progression due to defects in immunosuppressive functions of Tregs on macrophages. TKO mice exhibited increased lesion size as well as higher CD4⁺ T cells and macrophage content compared to WT mice. TKO plaques also showed increased necrotic cores along with defective macrophage efferocytosis. In contrast, adoptive cellular therapy using WT Tregs abrogated the accelerated lesion progression and deleterious effects in TKO mice. Intriguingly, RNA-seq analyses of TKO lesions revealed increased chemotaxis and cell proliferation, and reduced phagocytosis compared to WT lesions. Mechanistically, TKO-Tregs impaired the efferocytosis capacity of macrophages in vitro and promoted a pro-inflammatory macrophage phenotype via increased IFN-γ and decreased TGF-β secretion.

CONCLUSIONS

Taken together, these findings establish a critical role for KLF10 in regulating CD4⁺ Treg-macrophage interactions and atherosclerosis.

Developmental trichloroethylene exposure enhances predictive markers of autoimmunity in a sex-specific manner in disease-resistant female mice

Trichloroethylene (TCE) is a widely used industrial chemical and common environmental pollutant. Exposure to TCE promotes CD4⁺ T cell-driven autoimmunity including autoimmune hepatitis (AIH) in both humans and female autoimmune-prone mice. Because the developing immune system is more sensitive during development, we predicted that non- autoimmune-prone, C57/Bl6 (B6) mice would exhibit some autoimmune-related changes using the Developmental Origins of Health and Disease (DOHaD) model of exposure. Both male and female mice were exposed to vehicle or an environmentally relevant dose of 5 μg/ml TCE (0.9 mg/kg/day) beginning at 2 weeks pre-conception and ending at weaning. CD4+ T cells were assessed for phenotypic markers by flow cytometry. An assessment of cytokines elicited ex vivo after 4d polarization from naïve to CD4⁺ T helper subsets (i.e., Th1, Th17, and T reg) was conducted. mRNA expression of liver genes associated with inflammation, regeneration/repair associated with AIH disease progression in autoimmune-prone mice were evaluated by qRT-PCR. The results demonstrated TCE's ability to induce autoimmune- related biomarkers in B6 mice to an even greater degree in females compared to males when exposed during development.

Heterogeneity, subsets, and plasticity of T follicular helper cells in allergy

Antibody responses are critical for protection against pathogens. However, diseases such as allergic rhinitis or food allergy result from aberrant production of IgE antibodies against otherwise innocuous environmental antigens. The production of allergen-specific IgE requires interaction between B cells and CD4⁺ T cells, and a granular understanding of these interactions is required to develop novel therapies for allergic disease. CD4⁺ T cells are exceptionally heterogeneous in their transcriptional, epigenetic, and proteomic profiles, which poses significant challenges when attempting to define subsets relevant to the study of allergy among a continuum of cells. Defining subsets such as the T follicular helper (T_FH) cell cluster provides a shorthand to understand the functions of CD4⁺ T cells in antibody production and supports mechanistic experimentation for hypothesis-driven discovery. With a focus on allergic disease, this Rostrum article broadly discusses heterogeneity among CD4⁺ T cells and provides a rationale for subdividing T_FH cells into both functional and cytokine-skewed subsets. Further, it highlights the plasticity demonstrated by T_FH cells during the primary response and after recall, and it explores the possibility of harnessing this plasticity to reprogram immunity for therapeutic benefit in allergic disease.

Evaluation of tuberculosis diagnostic biomarkers in immunocompromised hosts based on cytokine levels in QuantiFERON-TB Gold Plus

Tuberculosis (TB) remains a serious health concern globally. QuantiFERON-TB (QFT) is a diagnostic tool for TB detection, and its sensitivity is reduced in immunocompromised hosts with low T lymphocyte counts or abnormal T cell function. This study aimed to evaluate the correlation between T cell and cytokine levels in patients with active TB using QFT-Plus. Forty-five patients with active TB were enrolled, and the cytokines in QFT-Plus tube supernatants were quantified using the MAGPIX System. CD4⁺ T cell count negatively correlated with patient age (p < 0.001, r = -0.51). The levels of TB1-responsive interleukin-1 receptor antagonist (IL-1Ra) and IL-2 correlated with CD4⁺ T cell count, whereas the levels of TB2-responsive IL-1Ra and IFN-γ-induced protein 10 correlated with both CD4⁺ and CD8⁺ T cell counts. Cytokines that correlated with CD4⁺ and CD8⁺ T cell counts might not be suitable TB diagnostic biomarkers in immunocompromised hosts. Notably, cytokines that did not correlate with the T cell counts, such as monocyte chemoattractant protein-1, might be candidate biomarkers for TB in immunocompromised hosts. Our findings might help improve TB diagnosis, which could enable prompt treatment and minimize poor disease outcomes.

The pro-inflammatory effect of triglyceride on human CD4+ T cells and experimental autoimmune uveitis

Aberrant lipid metabolism plays a role in inflammation and progression of autoimmune diseases but the definite mechanism remains unclear. In this study we investigate lipidomic profiles in Behçet's disease (BD) and the role of triglyceride (TAG) in the pathogenesis of autoimmune uveitis. Lipidomics revealed a distinct lipid metabolite profile including increased TAG metabolites in plasma of active BD patients. TAG could stimulate the proliferation, IL-17 and IFN-γ expression by CD4⁺ T cells and Th1, Th17 cell differentiation in vitro, but did not influence neutrophils. A922500 inhibited the TAG generation, ameliorated the EAU severity, decreased Th17 frequency and IL-17 expression by CD4⁺ T cells in vivo. The proteomocis analysis showed an up-regulation of apoptosis-related protein, Pik3r2, in CD4⁺ T cells from A922500-treated mice. In conclusion, TAG can stimulate human CD4⁺ T cells and the inhibition of its generation could significantly ameliorate EAU activity in association with down-regulated Th17 cell response.

Elevated β-secretase 1 expression mediates CD4+ T cell dysfunction via PGE2 signalling in Alzheimer's disease

Circulating CD4⁺ T cells are dysfunctional in Alzheimer's disease (AD), however, the underlying molecular mechanisms are not clear. In this study, we demonstrate that CD4⁺ T cells from AD patients and 5xFAD transgenic mice exhibit elevated levels of β-secretase 1 (BACE1). Overexpression of BACE1 in CD4⁺ T cells potentiated CD4⁺ T-cell activation and T-cell-dependent immune responses. Mechanistically, BACE1 modulates prostaglandin E2 (PGE2) synthetase-microsomal prostaglandin E synthase 2 (mPGES2)-to promote mPGES2 maturation and PGE2 production, which increases T-cell receptor (TCR) signalling. Moreover, administration of peripheral PGE2 signalling antagonists partially ameliorates CD4⁺ T cell overactivation and AD pathology in 5xFAD mice. Overall, our results reveal a potential role for BACE1 in mediating CD4⁺ T-cell dysfunction in AD.

Treg and IL-1 receptor type 2-expressing CD4+ T cell-deleted CD4+ T cell fraction prevents the progression of age-related hearing loss in a mouse model

We investigated the association between cellular immunity and age-related hearing loss (ARHL) development using three CD4⁺ T cell fractions, namely, naturally occurring regulatory T cells (Treg), interleukin 1 receptor type 2-expressing T cells (I1R2), and non-Treg non-I1R2 (nTnI) cells, which comprised Treg and I1R2-deleted CD4⁺ T cells. Inoculation of the nTnI fraction into a ARHL murine model, not only prevented the development of ARHL and the degeneration of spiral ganglion neurons, but also suppressed serum nitric oxide, a source of oxidative stress. Further investigations on CD4⁺ T cell fractions could provide novel insights into the prevention of aging, including presbycusis.

CD4+ T cell depletion does not affect the level of viremia in chronically SHIVSF162P3N-infected Chinese cynomolgus monkeys

Chronically SHIV_SF162P3N-infected cynomolgus monkeys were used to determine the effects of the antibody-mediated acute CD4⁺ T cell depletion on viral load as well as on the immunological factors associated with disease progression. Compared with the control animals, CD4⁺ T cell-depleted animals with SHIV infection showed (i) little alteration in plasma viral load over the period of 22 weeks after the depletion; (ii) increased CD4⁺ T cell proliferation and turnover of macrophages at the early phase of the depletion, but subsequent decline to the basal levels; and (iii) little impact on the expression of the inflammatory cytokines and CC chemokines associated with disease progression. These findings indicate that the antibody-mediated acute CD4⁺ T cell depletion had minimal impact on plasma viral load and disease progression in chronically SHIV_SF162P3N-infected cynomolgus monkeys. Future investigations are necessary to identify the key factor(s) related to the immune activation and macrophage infection during the CD4 deletion in chronic viral infection.

CD4+ and CD8+ cell populations in HIV-positive women with cervical squamous intra-epithelial lesions and squamous cell carcinoma

INTRODUCTION

This study aimed to analyse cervical lymphocytic populations in HIV+ and HIV- patients and correlate different cervical lesions with HIV viral load and presence of high-risk HPV types.

MATERIAL AND METHODS

A total of 132 histological specimens from 40 HIV+ and 72 HIV- patients were evaluated for CD4⁺ and CD8⁺ T cell distribution, presence of high-risk HPV types, peripheral blood HIV viral load and CD4⁺/CD8⁺ ratio.

RESULTS

High-grade squamous intraepithelial lesions (HSIL) and squamous cell carcinoma (SCC) from HIV+ patients had lower CD4⁺ T cell scores compared with HIV- patients. In all lesion groups, HIV+ patients presented higher epithelial and stromal CD8⁺ T cell scores. HIV viral load was more often detectable in patients with SCC than in those with low-grade squamous intraepithelial lesion (LSIL) (p = 0.0409). HSIL HIV+ patients had lower circulating CD4⁺ T cell counts (p = 0.0434) and CD4⁺/CD8⁺ ratio (p = 0.0378) compared with LSIL HIV+ patients. High-risk HPV types other than 16 and 18/45 were more prevalent in the HIV+ group.

DISCUSSION

These results support an imbalance between cervical CD4⁺ and CD8⁺ T lymphocytes of HIV+ patients with SIL and SCC, with increased CD8+ infiltrate density with lesion severity, even in patients with immune system recovery under cART.

N-Acetyldopamine derivatives from Periostracum Cicadae and their regulatory activities on Th1 and Th17 cell differentiation

Bioassay-guided fractionation of a 90% ethanol extract of Periostracum Cicadae led to the isolation of two new N-acetyldopamine dimers (1a/1b) along with six known dimers (2a/2b, 3a/3b, and 4a/4b) and two monomers (5a/5b); compounds 2a/2b, 4a/4b and 5a/5b were newly isolated from this material. All compounds were isolated as enantiomeric mixtures and each enantiomer was successfully separated by chiral-phase HPLC. The structures including absolute configurations were confirmed by high-resolution electrospray ionization mass spectrometry (HR-ESIMS), 1D/2D nuclear magnetic resonance (NMR) spectroscopy, ¹H iterative Full Spin Analysis (HiFSA), and electronic circular dichroism (ECD) spectroscopy. Subsequently, the bioactivities of these isolates were evaluated via CD4⁺ T cell differentiations, which are critical for immune responses and inflammation. The results revealed that compound 5b was observed to enhance the IFN-γ⁺ Th1 differentiation, which may have a potential for cancer immunotherapy.

Tetrameric PKM2 Activation Curbs CD4+ T Cell Overactivation

Angiari et al. recently reported that TEPP-46 induces PKM2 tetramerization, thereby inhibiting its nuclear translocation and suppressing CD4⁺ T cell activation, T helper (Th)1/Th17 cell development, and experimental autoimmune encephalomyelitis (EAE) development both in vitro and in vivo. Moreover, TEPP-46 suppresses T cell glycolysis. These findings identify PKM2 tetramerization as a potential therapeutic target.

Co-expression of master transcription factors determines CD4+ T cell plasticity and functions in auto-inflammatory diseases

Master CD4⁺ T cell lineage determined transcription factors are found to be dysregulated in pathogenesis of autoimmune and inflammatory diseases. CD4⁺ T cells categorized into different lineages based on their functions, cell surface markers and master transcription factors those required for expression of lineage specific cytokines. T-bet, GATA3, RORγt and Foxp3 are major transcription regulators of Th1, Th2, Th17 and Treg cells respectively. Significant progress has been made in understanding expression of lineage specific master regulators that drives CD4⁺ T cell differentiation. It is known that each CD4⁺ T cell lineage express precise determined transcription factor and due to cross regulation between these factors the CD4⁺ T cells able to maintain thier specific phenotype. However, recent studies shows that the lineage specifying transcription factors frequently co-expressed. There is an emerging area of research revealing that the co-expression of lineage-specifying transcription factors alters the potential function and flexibility of subsets of CD4⁺ T cell, this in turn favors the autoimmune pathology. Here, we discuss similarities and differences between mutually co-expressed transcription factors in CD4⁺ T cell subsets and then recapitulates on cell type specific and dynamic balance between the lineage restricted transcription factors in determining plasticity of CD4⁺ T cell subsets. Furthermore, we discuss abnormal regulation of such transcription factors that establishes a pathogenic CD4⁺ T cell phenotype in autoimmune diseases and how this understanding will provide further insight into potential therapeutic development.

The immunologic dominance of an epitope within a rationally designed poly-epitope vaccine is influenced by multiple factors

INTRODUCTION

CD4⁺ T cells are essential for inducing optimal CD8⁺ T cell and antibody-producing B cell responses and maintaining their long-term immunological memory. Therefore, CD4⁺ T cells are a critical component in HIV vaccine development. Due to enormous viral gene variation and significant human host genetic diversity, HIV vaccines may need to be custom-made for different countries.

METHODS

Previously, we designed a CD4⁺ T cell vaccine based on Chinese HIV isolates and HLA-DR alleles using bioinformatics tools and predicted that 20 epitopes could cover 98.1% of the Chinese population. In vivo testing of the poly-epitope antigen in mice only activated specific T cells for some epitopes. To elucidate the mechanism of the observed differential immunogenicity, we examined poly-epitope antigen processing and presentation using in vitro and in vivo analytical methods.

RESULTS

Enzymatic digestion indicated that all 20 epitopes comprising the poly-epitope antigen could be liberated, but MHC II binding assays showed that neither binding affinity nor dissociation rate was associated with the magnitude of T cell immune responses elicited by each peptide epitope in vaccinated mice. Mass spectrometry analysis of MHC II-bound peptides suggested that the abundance of endogenously processed peptides bound to MHC II molecules was significantly associated with the relative immunodominance of these epitopes.

CONCLUSION

These results provide a new rationale for improving the design and testing of poly-epitope vaccines for HIV and other diseases.

Siglec-10 expression is up-regulated in activated human CD4+ T cells

Most sialic acid-binding immunoglobulin-like lectins (Siglecs) suppress immune cell function but are expressed at low levels on human T cells. We found that soluble CD52 inhibited T cell signalling by ligating Siglec-10, but the presence of Siglec-10 on human T cells has been questioned. To address this concern, we examined the expression of Siglec-10 at the RNA and protein level in human CD4⁺ T cells. Analysis by RNAseq, qPCR and flow cytometry demonstrated that, in contrast to other Siglecs, after activation of CD4⁺ T cells Siglec-10 was selectively upregulated in a subset of cells also high for CD52 expression. This observation is consistent with a homeostatic role for Siglec-10 in human CD4⁺ T cells.

CD8+ T cells regulated by CD4+CD25+ regulatory T cells in the early stage exacerbate the development of Dermatophagoides farinae-induced skin lesions via increasing mast cell infiltration in mice

Atopic dermatitis is a chronic inflammatory skin disease associated with CD4⁺ Th2 cell-shifted immune responses. Although the infiltration of skin lesions by CD8⁺ T cells has been recognized, their roles have not been fully defined. In this study, we examined the relationship between CD4⁺ and CD8⁺ cells in antigen-induced skin lesions of mice. BALB/c mice were repeatedly challenged with Dermatophagoides farinae (Der f) applied to the right ear nine times. Pre-treatment with anti-CD4 monoclonal antibody (mAb) during the third to sixth challenges, but not the post-treatment during the sixth to ninth challenges, exacerbated the development of Der f-induced ear swelling; pre-treatment with anti-CD25 mAb, which depletes regulatory T cells (Tregs), also exacerbated the lesions. Furthermore, the number of CD8⁺ T cells in lymph nodes was augmented by these pre-treatments. These findings prompted us to examine the effect of anti-CD8 mAb. Pre-treatment with anti-CD8 mAb, but not post-treatment, strongly inhibited the development of Der f-induced ear swelling; additionally, the epidermal hyperplasia and infiltration of mast cells were inhibited by the pre-treatment. Collectively, we revealed that CD8⁺ T cells regulated by CD4⁺CD25⁺ Tregs in the early stage are key contributors to the development of Der f-induced skin lesions via increasing mast cell infiltration, indicating that CD8⁺ T and Tregs could be potential therapeutic targets for atopic dermatitis.

Lymphocyte DNA methylation mediates genetic risk at shared immune-mediated disease loci

Background

Defining regulatory mechanisms through which noncoding risk variants influence the cell-mediated pathogenesis of immune-mediated disease (IMD) has emerged as a priority in the post–genome-wide association study era.

Objectives

With a focus on rheumatoid arthritis, we sought new insight into genetic mechanisms of adaptive immune dysregulation to help prioritize molecular pathways for targeting in this and related immune pathologies.

Methods

Whole-genome methylation and transcriptional data from isolated CD4⁺ T cells and B cells of more than 100 genotyped and phenotyped patients with inflammatory arthritis, all of whom were naive to immunomodulatory treatments, were obtained. Analysis integrated these comprehensive data with genome-wide association study findings across IMDs and other publicly available resources.

Results

We provide strong evidence that disease-associated DNA variants regulate cis-CpG methylation in CD4⁺ T and/or B cells at 37% RA loci. Using paired, cell-specific transcriptomic data and causal inference testing, we identify examples where site-specific DNA methylation in turn mediates gene expression, including FCRL3 in both cell types and ORMDL3/GSDMB, IL6ST/ANKRD55, and JAZF1 in CD4⁺ T cells. A number of genes regulated in this way highlight mechanisms common to RA and other IMDs including multiple sclerosis and asthma, in turn distinguishing them from osteoarthritis, a primarily degenerative disease. Finally, we corroborate the observed effects experimentally.

Conclusions

Our observations highlight important mechanisms of genetic risk in RA and the wider context of immune dysregulation. They confirm the utility of DNA methylation profiling as a tool for causal gene prioritization and, potentially, therapeutic targeting in complex IMD.

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.

Predicting drug-free remission in rheumatoid arthritis: A prospective interventional cohort study

BACKGROUND

Many patients with rheumatoid arthritis (RA) achieve disease remission with modern treatment strategies. However, having achieved this state, there are no tests that predict when withdrawal of therapy will result in drug-free remission rather than flare. We aimed to identify predictors of drug-free remission in RA.

METHODS

The Biomarkers of Remission in Rheumatoid Arthritis (BioRRA) Study was a unique, prospective, interventional cohort study of complete and abrupt cessation of conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs). Patients with RA of at least 12 months duration and in clinical and ultrasound remission discontinued DMARDs and were monitored for six months. The primary outcome was time-to-flare, defined as disease activity score in 28 joints with C-reactive protein (DAS28-CRP) ≥ 2.4. Baseline clinical and ultrasound measures, circulating inflammatory biomarkers, and peripheral CD4+ T cell gene expression were assessed for their ability to predict time-to-flare and flare/remission status by Cox regression and receiver-operating characteristic (ROC) analysis respectively.

RESULTS

23/44 (52%) eligible patients experienced an arthritis flare after a median (IQR) of 48 (31.5-86.5) days following DMARD cessation. A composite score incorporating five baseline variables (three transcripts [FAM102B, ENSG00000228010, ENSG00000227070], one cytokine [interleukin-27], one clinical [Boolean remission]) differentiated future flare from drug-free remission with an area under the ROC curve of 0.96 (95% CI 0.91-1.00), sensitivity 0.91 (0.78-1.00) and specificity 0.95 (0.84-1.00).

CONCLUSION

We provide proof-of-concept evidence for predictors of drug-free remission in RA. If validated, these biomarkers could help to personalize immunosuppressant withdrawal: a therapy paradigm shift with ensuing patient and economic benefits.

LncRNA PVT1 links Myc to glycolytic metabolism upon CD4+ T cell activation and Sjögren's syndrome-like autoimmune response

The hyperproliferation and hyperactivation of CD4⁺ T cells in salivary gland tissue is a hallmark of Sjögren's syndrome (SS). However, the role of long noncoding RNAs (lncRNAs) in the pathological process of SS and CD4⁺ T cell activation has not been fully elucidated. Here, we reported that lncRNA PVT1 was involved in the glycolytic metabolism reprogramming and proliferation upon CD4⁺ T cell activation. Expression of PVT1 was positively related with CD4⁺ T cell activation both in SS patients and Ex vivo antigen simulation. Depletion of PVT1 decreased the proliferation of murine CD4⁺ T cells and Jurkat T cells upon activation. We also showed that expression of the transcription factor Myc is regulated by PVT1 under antigen simulation. Depletion of PVT1 significantly decreased the expression of glycolytic genes, as well as several pivotal glycolytic proteins that were directly transcribed by Myc. Measurement of glucose content and lactate secretion indicated a defected lactate secretion and glucose uptake in PVT1-depleted T cells. Additionally, the real-time extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) measurement also affirmed that PVT1 maintains glycolytic levels, glycolytic capacity under stress and ECAR/OCR ratios during T cell activation. Polarizing assays indicate that PVT1 depletion defected the function of Th1 effector cells as well as down-regulated Myc expression and glycolytic levels. Furthermore, we observed increased glycolytic levels in CD4⁺ T cells from SS-like NOD/Ltj mice. Treatment with 2-deoxy-d-glucose (2-DG), an inhibitor of glycolysis, significantly decreased the extent of lymphocyte infiltration and CD4⁺ T cell numbers and attenuated the defect of salivary flow in the lesioned submandibular glands of NOD/Ltj mice. Thus, our study demonstrated that lncRNA PVT1, which was upregulated in the CD4⁺T cells of SS patients, could maintain the expression of Myc, thus controlling the proliferation and effector functions of CD4⁺ T cells through regulating the reprogramming of glycolysis. Inhibition of glycolysis could attenuate the proliferation of CD4⁺ T cells and the SS-like autoimmune response. Our study provides a novel mechanistic function of lncRNA PVT1 in the pathogenesis of SS.

Long-lasting neurobehavioral alterations in burn-injured mice resembling post-traumatic stress disorder in humans

OBJECTIVE

To establish an animal model for posttraumatic stress disorder in burn-injured patients.

METHODS

Thermal-injured mice with 15% total body surface area were subjected to a series of neurobehavioral tests at 1 and 3 months postburn. Brains were collected for analysis of key molecules expression, spleens for T cell function analysis, and blood for biochemistry and hormones detection.

RESULTS

Comparison with sham mice, burn mice showed extremely high locomotion in homecage, open field, and forced swimming tests, indicating a hyper-arousal state. Burn mice exhibited improved spatial memory in Morris Water Maze test and heightened context fear memory in context fear conditioning, suggesting re-experiencing behavior. Although burn mice showed pronounced passive avoidance in the step-through test, their active avoidance capability in response to the conditional stimulus in the shuttle box test was relatively deteriorated. Likewise, the retention of cue-feared memory was impaired in fear conditioning test. The above negative alterations in mood were recapitulated in open-field test, in which the burn mice displayed an anxiety-like behavior with less time spent in the center. However, no sign of depression was found in the forced swimming and sucrose preference tests. The negative mood of burn mice was reinforced by a deficit in sociality and preference for social novelty in social interaction test. These neurobehavioral alterations were associated with an increased expression of brain-derived neurotrophic factor along with a remarkable microgliosis and a moderate astrocytosis in the brain of burn vs. sham mice. Moreover, a prominent Th2 switch and consequent increased nuclear NF-κB translocation were seen in the splenic T cells from burn relative to sham mice.

CONCLUSIONS

We conclude that even mild burn injury could lead to long-lasting cognitive and effective alterations in mice. These findings shed light on the interactions among neuropsychology, neurobiology, and immunology throughout the recovery period of burn injury.

Estrogen receptor β activation ameliorates DSS-induced chronic colitis by inhibiting inflammation and promoting Treg differentiation

Estrogen receptor (ER) β activation has anti-inflammatory activity. However, its effect on the development of inflammatory bowel disease (IBD) and the underlying mechanism have not been clarified. This study aimed to assess the clinical value of ERβ⁺CD4⁺ T cells in IBD patients and examine the anti-inflammatory role of ERβ activation in dextran sulfate sodium (DSS)-induced chronic colitis in mice. We investigated the effects of ERB041 (an ERβ-specific agonist) on inflammatory cytokines and pro-inflammatory T-cell and regulatory T-cell (Treg) responses in murine colitis. We tested the role of ERβ activation on Treg differentiation and its activity to suppress T-cell proliferation in vitro. We found that reduced frequency of circulating ERβ⁺CD4⁺ T cells in IBD patients was negatively correlated with inflammation and disease severity. ERβ and FoxP3 expression co-localized in the intestinal tissues of IBD patients. Treatment with ERB041 significantly mitigated colitis-induced weight loss, inflammation, and disease severity. It also restored the ERβ⁺CD4⁺ T cell population in the spleen and colon lamina propria of these mice. ERB041 treatment inhibited CD4⁺CD25^- and CD8⁺ T cell infiltration and restored Tregs and activated T-cell immunoreceptor with Ig and ITIM domains (TIGIT)⁺ Tregs in the colon lamina propria. In vitro, we found that ERβ activation enhanced Treg differentiation, immunosuppression, and TGF-β1/Smad signaling in CD4⁺ T cells. Our data suggest that ERβ⁺CD4⁺ T cells represent a potential biomarker for evaluating IBD disease severity, and ERβ activation may be valuable for the treatment of IBD by enhancing the Treg response.

The role of type I interferons in CD4+ T cell differentiation

Type I interferons (IFNs) released upon viral infections play different and opposing roles in disease outcome. This pleiotropic effect is mainly influenced by the cellular sources, timing and target cells for these molecules. The effect of type I IFN signaling on the activation and differentiation of antiviral CD4⁺ T cells remains ill defined, with studies reporting either a beneficial or a detrimental role, depending on the context of infection. This review will highlight several recent studies that have investigated the role of type I IFNs in the priming and polarization of CD4⁺ T cells and discuss areas of uncertainty that require further investigation.

Dual effect of T helper cell 17 (Th17) and regulatory T cell (Treg) in liver pathological process: From occurrence to end stage of disease

Liver disease is a complicated pathological status with acute or chronic progressions, causing a series of damages to liver and massive burden to public health and society. Th17 and Treg, two subsets of CD4⁺ T helper cells, seem to keep a subtle balance in the maintenance of organic immune homeostasis including liver. The dysfunction of Th17/Treg balance in liver has been proved associated with hepatic injury and disease. Herein, we summarized the research advance of Th17 and Treg cells in different phenotypes of liver diseases in the past decade. It is known to all that hepatic diseases start from stimulations or infections like virus, autoimmune, alcohol and so on in the early stage, which would cause inflammation. With the disease consistently existed, severe outcomes like cirrhosis and hepatocellular carcinoma appear finally. In conclusion, it is found that Th17 and Treg cells serve as an important role in the immune response imbalance of liver diseases from the beginning to the end stage. However, the effect of these two subsets of CD4⁺ T helper cells is not a stereotype. Pathological role which exacerbates the disease and protective character which inhibits damage to liver are co-existed in the effect of Th17 and Treg cells. Still, more studies should be carried out to enrich the understandings of liver disease and Th17/Treg immune balance in the future.

Role of leukotriene B4 12-hydroxydehydrogenase in α-galactosylceramide-pulsed dendritic cell therapy for non-small cell lung cancer

Invariant natural killer T (iNKT) cells exhibit potent antitumor effects upon activation by recognizing a specific glycolipid antigen. We previously performed phase I-II clinical studies to utilize iNKT cells using α-galactosylceramide-pulsed dendritic cells and identified leukotriene B4 12-hydroxydehydrogenase (LTB4DH) as a biomarker highly expressed in T cells derived from non-small cell lung cancer (NSCLC) patients who showed prolonged survival in respond to the iNKT cell immunotherapy. Because LTB4DH expression correlated with prolonged survival of NSCLC patients, we considered LTB4DH to play a role in iNKT cell immunotherapy. We herein demonstrate that the overexpression of LTB4DH in CD4⁺ or CD8⁺ T cells increases interferon-γ production and tumoricidal activity in the presence of prostaglandin E₂. Moreover, the expression of granzyme a, granzyme b, and perforin mRNA was increased in LTB4DH-overexpressing cells.

Effects of anti-allergic drugs on T cell-mediated nasal hyperresponsiveness in a murine model of allergic rhinitis

BACKGROUND

We have recently demonstrated that T cell-mediated nasal hyperresponsiveness (NHR) is a representative pathophysiological feature of allergic rhinitis (AR). Although several anti-allergic drugs are used for the treatment of AR, the efficacy of these drugs on T cell-mediated NHR have not been elucidated. In these studies we investigated the effects of dexamethasone (Dex), montelukast (Mk), and chlorpheniramine (Chl) on NHR in antigen-immunized and antigen-specific Th2 cell-transferred mice.

METHODS

OVA-immunized BALB/c mice were treated with Dex, Mk, or Chl and challenged intranasally with OVA. We then assessed NHR, the number of inflammatory cells in the nasal lavage fluid (NALF), mRNA expression of Th2 cytokines in the nasal tissue, the population of CD3⁺CD4⁺ cells in the nasal lymphoid tissue (NALT), and antigen-specific serum IgE and IgG levels. Antigen-induced NHR and changes in antigen-specific T cells in the NALT were investigated in OVA-specific Th2 cell-transferred mice.

RESULTS

Dex significantly suppressed antigen-induced NHR, inflammatory cell infiltration, and IL-4, IL-5, IL-6, and IL-13 expression in immunized mice. Chl was completely ineffective, and only IL-13 expression was suppressed by Mk. None of these drugs affected IgE and IgG production. Antigen-induced NHR and the increase in antigen-specific T cells in the NALT of Th2 cell-transferred mice were inhibited by Dex, but not by Mk or Chl.

CONCLUSIONS

Steroids are effective for the reduction of NHR in AR by suppressing the accumulation of inflammatory cells, especially antigen-specific T cells.

CCDC134 ameliorated experimental autoimmune encephalomyelitis by suppressing Th1 and Th17 cells

CCDC134 (coiled-coil domain containing 134), a cytokine-like molecule, was previously reported to exert antitumor effects by augmenting CD8⁺ T-cell mediated immunity. However, the dynamic changes in CCDC134 expression patterns in the spinal cord that may be involved in the progression of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, remains unclear. In this study, we found that CCDC134 expression was markedly increased in the spinal cord during the progression of EAE. Furthermore, we demonstrated that CCDC134 significantly reduced the severity and slowed the progression of EAE, which correlated with reduced spinal cord inflammation and demyelination. The underlying mechanism of CCDC134-induced effects involved inhibition of T helper (Th)-1 and Th17 cell differentiation and secretion of its key effector molecules IFN-γ and IL-17A via regulation of JAK/STAT signaling. These findings indicate that CCDC134 exerts potent anti-inflammatory effects through the selective modulation of pathogenic Th1 and Th17 cells by targeting critical signaling pathways. The study provides insights into the role of CCDC134 as a unique therapeutic agent for the treatment of autoimmune diseases.

MiR-200a expression in CD4+ T cells correlates with the expression of Th17/Treg cells and relevant cytokines in psoriasis vulgaris: A case control study

The main aim of this study is to investigate the underlying relationship shared between microRNA-200a (miR-200a) and its link to concentrations of Th17 and Treg cells, mRNA expressions of their specific transcription factors retinoic acid-related orphan receptor γt (RORγt) and head box protein 3 (FOXP3) and relevant cytokines in patients with psoriasis vulgaris (PV). A total of 189 patients previously diagnosed with PV were selected as the experimental group, whilst 109 healthy individuals as the control group. According to the psoriasis area and severity index (PASI), subjects in the experimental group were assigned into the severe group (95 cases) and the moderate group (94 cases). CD4⁺ T and Th17/Treg cells were extracted. MiR-200a expression and RORγt and FoxP3 mRNA expressions were detected by qRT-PCR. Concentrations of Th17 and Treg cells were measured via flow cytometry. ELISA was conducted for serum IL-17, IL-23 and TGF-β levels. Correlation analysis was completed in accordance with the Pearson method. Compared with the moderate group, higher miR-200a expression, RORγt mRNA expression, percentage of Th17, Th17/Treg ratio and levels of IL-17 and IL-23 exhibited in the severe group, whilst FoxP3 mRNA expression and, percentage of Treg as well as TGF-β were lower. A same trend displayed when comparing the moderate group to the control group. We found that miR-200a expression, percentage of Th17, Th17/Treg ratio, IL-17 and IL-23 levels and RORγt mRNA expression are positively correlated with PASI grade, while the percentage of Treg, TGF-β level and FoxP3 mRNA expression are negatively correlated with PASI grade. The results also displayed that the percentage of Th17, Th17/Treg ratio, IL-17 and IL-23 levels and RORγt mRNA expression are positively correlated with miR-200a expression, while the percentage seen in Treg and TGF-βand FoxP3 mRNA expression are negatively correlated with miR-200a expression. Our results provided a strong evidence that up-regulation of microRNA-200a in CD4+ T cells may induce immune dysfunction through Th17/Treg cells and relevant cytokines in PV patients.

Microarray analysis of lncRNA and mRNA expression profiles in mice with allergic rhinitis

OBJECTIVES

We aimed to identify the effect of lncRNAs in CD4⁺ T cells on Allergic rhinitis (AR).

METHODS

The present study conducted a microarray to identify the expression profiles of lncRNA and mRNA in CD4⁺ T cells in both AR murine models and normal controls. And qRT-PCR was used to confirm the results. GO and KEGG enrichment analysis were used to show all related pathways and a co-expression network was conducted to find lncRNAs which have high correlation with these pathways.

RESULTS

The results showed that the two groups contained a total of 158 deregulated lncRNAs, of which 110 were upregulated and 48 were downregulated. And positive regulation of calcium ion transport, B cell activation, chemokine-signaling pathways and calcium-signaling pathways may be involved in the development of T cells in AR pathology. Finally, we can find the differentially expressed mRNA in the pathways related to T cell differentiation correlated with many deregulated lncRNAs.

CONCLUSIONS

The present study was the first to show the differential expression profiles of lncRNAs in the CD4⁺ T cells of an AR murine model, which may provide significant insights into AR pathogenesis and offer new treatment targets to alleviate it.

Over-expression of CD8+ T-cell activation is associated with decreased CD4+ cells in patients seeking treatment of Alcohol Use Disorder

INTRODUCTION

Harmful alcohol consumption may have an impact on the adaptive immune system through an imbalance in T cell subpopulations and changes in cell activation. We aimed to analyze profiles of CD4 and CD8T cell activation in patients with alcohol use disorder (AUD).

METHODS

We used a cross-sectional study with patients seeking treatment of the disorder. Blood samples for immunophenotyping were obtained at admission. Profiles of T cell activation were defined: (I) CD38⁺/HLA-DR⁺, (II) CD38⁺/HLA-DR^-, (III) CD38^-/HLA-DR⁺, (IV) CD38^-/HLA-DR^- and compared with healthy controls. We calculated a CD8⁺ T cell activation indicator (AI) that was defined as the quotient of non-activated cells (CD38^-/HLA-DR^-) and activated cells (CD38⁺/HLA-DR⁺).

RESULTS

60 patients were eligible (83%M); median age was 49 years [IQR: 44-54] and alcohol consumption was 145g/day [IQR: 90-205]. Mean±SD of CD38⁺/HLA-DR^- was 50.3±50.6 cells/μL in patients and 33.5±24.5 cells/μL in controls (p=0.03), for the CD38^-/HLA-DR⁺ it was 61±62.2 cells/μL in patients and 21.2±17.3 cells/μL in controls (p<0.001) and for the CD38⁺/HLA-DR⁺ it was 20.2±15.6 cells/μL in patients and 10.8±10.3 cells/μL in controls (p<0.001). In patients, an inverse correlation was observed between absolute number and percentage of CD4⁺ T cells, and the percentage of CD38⁺/HLA-DR⁺CD8⁺ T cells (r=0.37, p=0.003; r=0.2, p=0.086, respectively).

CONCLUSIONS

Patients with AUD have an increased expression of immune activation with respect to healthy individuals. This excess of activated CD8⁺ T cells correlates with the absolute CD4⁺ T cells.

Identification and characterization of CD4+ T cell epitopes on manganese transport protein C of Staphylococcus aureus

Manganese transport protein C (MntC) of Staphylococcus aureus represents an excellent vaccine-candidate antigen. The important role of CD4⁺ T cells in effective immunity against S. aureus infection was shown; however, CD4⁺ T cell-specific epitopes on S. aureus MntC have not been well identified. Here, we used bioinformatics prediction algorithms to evaluate and identify nine candidate epitopes within MntC. Our results showed that peptide M8 emulsified in Freund's adjuvant induced a much higher cell-proliferation rate as compared with controls. Additionally, CD4⁺ T cells stimulated with peptide M8 secreted significantly higher levels of interferon-γ and interleukin-17A. These results suggested that peptide M8 represented an H-2d (I-E)-restricted Th17-specific epitope.

Screening of an FDA-approved compound library identifies levosimendan as a novel anti-HIV-1 agent that inhibits viral transcription

Combination antiretroviral therapy (cART) has been proven to efficiently inhibit ongoing replication of human immunodeficiency virus type 1 (HIV-1), and significantly improve the health outcome in patients of acquired immune deficiency syndrome (AIDS). However, cART is unable to cure HIV-1/AIDS. Even in presence of cART there exists a residual viremia, contributed from the viral reservoirs of latently infected HIV-1 proviruses; this constitutes a major hurdle. Currently, there are multiple strategies aimed at eliminating or permanently silence these HIV-1 latent reservoirs being intensely explored. One such strategy, a recently emerged "block and lock" approach is appealing. For this approach, so-called HIV-1 latency-promoting agents (LPAs) are used to reinforce viral latency and to prevent the low-level or sporadic transcription of integrated HIV-1 proviruses. Although several LPAs have been reported, there is still a question of their suitability to be further developed as a safe and valid therapeutic agent for the clinical use. In this study, we aimed to identify new potential LPAs through the screening an FDA-approved compound library. A new and promising anti-HIV-1 inhibitor, levosimendan, was identified from these screens. Levosimendan is currently used to treat heart failure in clinics, but it demonstrates strong inhibition of TNFα-induced HIV-1 reactivation in multiple cell lines of HIV-1 latency through affecting the HIV-1 Tat-LTR transcriptional axis. Furthermore, we confirmed that in primary CD4⁺ T cells levosimendan inhibits both the acute HIV-1 replication and the reactivation of latent HIV-1 proviruses. As a summary, our studies successfully identify levosimendan as a novel and promising anti-HIV-1 inhibitor, which should be immediately investigated in vivo given that it is already an FDA-approved drug.

Preliminary study of histamine H4 receptor expressed on human CD4+ T cells and its immunomodulatory potency in the IL-17 pathway of psoriasis

BACKGROUND

Previous studies have shown the expression of histamine H₄ receptor (H4R) on CD4⁺ T cells, especially human CD4⁺ T_h2-polarized T cells.

OBJECTIVE

This study aimed to investigate the role of H4R on these effector T cells in psoriasis.

METHODS

We enrolled three patients each with active psoriasis, inactive psoriasis, scalp seborrheic dermatitis, and three normal controls, and compared the basal expression of H4R mRNA in their peripheral blood CD4⁺ T cells. Then, we identified H4R expression in dermal CD4⁺ T cells. Furthermore, we investigated H4R expression after stimulating separated peripheral blood CD4⁺ T cells with several inflammatory cytokines.

RESULTS

The results showed higher H4R expression in the active psoriasis group compared to the inactive psoriasis group. It was interesting that interleukin (IL)-23, which is a representative cytokine contributing to T_h17 cell differentiation, stimulated H4R expression significantly. After adding a selective H4R antagonist (JNJ-7777120) while the CD4⁺ T cells were polarized into T_h17 cells, we observed a tendency toward suppressed IL-17 secretion.

CONCLUSIONS

Histamine stimulation influences the IL-17 pathway in psoriasis via the fourth histamine receptor subtype, H4R, on CD4⁺ T cells. The immunomodulatory roles of H4R suggest its potency as a new therapeutic target for obstinate psoriasis.

MST1 deficiency promotes B cell responses by CD4+ T cell-derived IL-4, resulting in hypergammaglobulinemia

MST1 deficiency causes T and B cell lymphopenia, resulting in combined immunodeficiency. However, MST1-deficient patients also exhibit autoimmune-like symptoms such as hypergammaglobulinemia and autoantibody production. Recent studies have shown that the autoimmune responses observed in MST1-deficient patients were most likely attributable to defective regulatory T (Treg) cells instead of intrinsic signals in MST1-lacking B cells. Nevertheless, it is not determined how MST1 deficiency in T cells breaks B cell tolerance and causes systemic autoimmune-like phenotypes. In this study, we confirmed that Mst1^-/- mice developed hypergammaglobulinemia associated with increased levels of IgG, IgA, and IgE. We also showed that uncontrolled B cell responses were resulted from the IL-4-rich environment created by CD4⁺ T cells. Defective MST1-FOXO1 signaling down-regulated Treg cells, resulting in the collapse of immune tolerance where the populations of Th2 and T follicular helper cells expanded. In conclusion, we suggest that MST1 acts as a molecular brake to maintain immune tolerance by regulating T cell-mediated B cell activation.

Expansion and retention of pulmonary CD4+ T cells after prime boost vaccination correlates with improved longevity and strength of immunity against tularemia

Francisella tularensis subsp. tularensis strain SchuS4 (Ftt) is a highly virulent intracellular bacterium. Inhalation of 10 or fewer organisms results in an acute and potentially lethal disease called pneumonic tularemia. Ftt infections occur naturally in the U.S. and Ftt was developed as a bioweapon. Thus, there is a need for vaccines that protect against this deadly pathogen. Although a live vaccine strain of Francisella tularensis (LVS) exists, LVS fails to generate long-lived protective immunity against modest challenge doses of Ftt. We recently identified an important role for high avidity CD4⁺ T cells in short-term protection and hypothesized that expanding this pool of cells would improve overall vaccine efficacy with regard to longevity and challenge dose. In support of our hypothesis, application of a prime/boost vaccination strategy increased the pool of high avidity CD4⁺ T cells which correlated with improved survival following challenge with either increased doses of virulent Ftt or at late time points after vaccination. In summary, we demonstrate that both epitope selection and vaccination strategies that expand antigen-specific T cells correlate with superior immunity to Ftt as measured by survival.

MAP4K4 deficiency in CD4(+) T cells aggravates lung damage induced by ozone-oxidized black carbon particles

As the main composition of combustion, black carbon (BC) is becoming more and more noticeable at home and abroad. Ozone-oxidized black carbon (oBC) was produced through aging of ozone, one of the near-surface pollutants, to black carbon. And oBC was found to be more oxidation and cell toxicity when compared with BC. Besides, as a key cell of immunity, whether CD4(+) T cell would involve in lung inflammation induced by particular matter is still unclear. This study aims to observe the effect of oBC on lung damage in mice and discuss how the functional MAP4K4 defect CD4(+) T cells (conditional knockout of MAP4K4) presents its role in this process. In our study, MAP4K4 deletion in CD4(+) T cells (MAP4K4 cKO) could increase cell number of macrophages, lymphocytes and neutrophils in bronchoalveolar lavage fluid (BALF) exposed to oBC. MAP4K4 deletion in CD4(+) T cell also affected CD4(+) T cell differentiation in mediastinal lymph nodes after oBC stimulation. The number of CD4(+) IL17(+) T cell increased obviously. The levels of IL-6 mRNA of lung in MAP4K4 cKO mice was higher than that in wild type mice after exposed to oBC, while the level of IL-6 in BALF had the same trend. Histological examination showed that MAP4K4 deletion in CD4(+) T cells affected lung inflammation induced by oBC. Results indicated that MAP4K4 cKO in CD4(+) T cells upgraded the level of inflammation in lung when exposed to oBC, which may be connected to the CD4(+) T cell differentiation and JNK, ERK and P38 pathways.

Identification and characterization of CD4+ T cell epitopes present in Trichinella spiralis paramyosin

Trichinellosis is a worldwide zoonosis and vaccinating swine with a potent vaccine is a practical approach to prevent Trichinella infections in China. Paramyosin of T. spiralis (Ts-Pmy) was shown in our previous work to be a good vaccine candidate against Trichinella infections. Because CD4⁺ T cells play a crucial role in effective immunity against T. spiralis infection, identifying CD4⁺ T cell epitopes of paramyosin is crucial for constructing a chimeric subunit epitope vaccine. Twelve CD4⁺ T cell epitopes of Ts-Pmy with the highest scores were predicted and synthesized as peptides. Five of the twelve peptides, P2, P3, P4, P5 and P12, induced strong splenocyte proliferation and secretion of the Th2 cytokines IL-4 and IL-5 from rTs-Pmy-immunized mouse splenocytes. To assess the immunogenicity of CD4⁺ T cell epitopes in vivo, splenocytes from mice immunized with individual peptides were stimulated with the corresponding peptides. P2, P3, P4 and P5 induced strong cell proliferation and secretion of both Th1 (INF-γ, IL-2) and Th2 (IL-4, IL-5) cytokines. The results indicate that the peptides P2, P3, P4 and P5 are immunodominant CD4⁺ T cell epitopes of Ts-Pmy. This study will facilitate the design of an effective epitope-based multivalent subunit vaccine against Trichinella infections.

Impact of adjuvants on CD4(+) T cell and B cell responses to a protein antigen vaccine: Results from a phase II, randomized, multicenter trial

Immunogenicity and safety of different adjuvants combined with a model antigen (HBsAg) were compared. Healthy HBV-naïve adults were randomized to receive HBs adjuvanted with alum or Adjuvant Systems AS01B, AS01E, AS03A or AS04 at Days 0 and 30. Different frequencies of HBs-specific CD4+ T cells 14days post dose 2 but similar polyfunctionality profiles were induced by the different adjuvants with frequencies significantly higher in the AS01B and AS01E groups than in the other groups. Antibody concentrations 30days post-dose 2 were significantly higher in AS01B, AS01E and AS03A than in other groups. Limited correlations were observed between HBs-specific CD4+ T cell and antibody responses. Injection site pain was the most common solicited local symptom and was more frequent in AS groups than in alum group. Different adjuvants formulated with the same antigen induced different adaptive immune responses and reactogenicity patterns in healthy naïve adults. The results summary for this study (GSK study number 112115 - NCT# NCT00805389) is available on the GSK Clinical Study Register and can be accessed at www.gsk-clinicalstudyregister.com.

Assessment of the antiviral capacity of primary natural killer cells by optimized in vitro quantification of HIV-1 replication

Despite a growing number of studies investigating the impact of natural killer (NK) cells on HIV-1 pathogenesis, the exact mechanism by which NK cells recognize HIV-1-infected cells and exert immunological pressure on HIV-1 remains unknown. Previously several groups including ours have introduced autologous HIV-1-infected CD4(+) T cells as suitable target cells to study NK-cell function in response to HIV-1 infection in vitro. Here, we re-evaluated and optimized a standardized in vitro assay that allows assessing the antiviral capacity of NK cells. This includes the implementation of HIV-1 RNA copy numbers as readout for NK-cell-mediated inhibition of HIV-1 replication and the investigation of inter-assay variation in comparison to previous methods, such as HIV-1 p24 Gag production and frequency of p24(+) CD4(+) T cells. Furthermore, we investigated the possibility to hasten the duration of the assay and provide concepts for downstream applications. Autologous CD4(+) T cells and NK cells were obtained from peripheral blood of HIV-negative healthy individuals and were separately enriched through negative selection. CD4(+) T cells were infected with the HIV-1 strain JR-CSF at an MOI of 0.01. Infected CD4(+) T cells were then co-cultured with primary NK cells at various effector:target ratios for up to 14days. Supernatants obtained from media exchanged at days 4, 7, 11 and 14 were used for quantification of HIV-1 p24 Gag and HIV-1 RNA copy numbers. In addition, frequency of infected CD4(+) T cells was determined by flow cytometric detection of intracellular p24 Gag. The assay displayed minimal inter-assay variation when utilizing viral RNA quantification or p24 Gag concentration for the assessment of viral replication. Viral RNA quantification was more rigorous to display magnitude and kinetics of NK-cell-mediated inhibition of HIV-1 replication, longitudinally and between tested individuals. The results of this study demonstrate that NK-cell-mediated inhibition of HIV-1 replication can be reliably quantified in vitro, and that viral RNA quantification is comparable to p24 Gag quantification via ELISA, providing a robust measurement for NK-cell-mediated inhibition of viral replication. Overall, the described assay provides an optimized tool to study the antiviral capacity of NK cells against HIV-1 and an additional experimental tool to investigate the molecular determinants of NK-cell recognition of virus-infected cells.

High-dose cyclophosphamide induces specific tumor immunity with concomitant recruitment of LAMP1/CD107a-expressing CD4-positive T cells into tumor sites

Cancer chemotherapy regimens, particularly those employing high-dose cytotoxic drugs such as cyclophosphamide (CTX), have been considered to be immune suppressive. However, we observed that a single administration of high-dose CTX abolished tumors arising from subcutaneous injection of a mouse hepatoma cell line and subsequently induced specific tumor immunity. Depletion of T cells, specifically CD4(+) T cells, abrogated the CTX-mediated tumor regression. CTX treatment induced the rapid recruitment of CD4(+) T cells into the tumors, and these recruited cells initiated expression of LAMP1/CD107a, a cytotoxic granule molecule, and granzyme B in the absence of antigen presentation at draining lymph nodes and proliferation in the tumor tissues. Moreover, CTX enhanced the expression of a CC chemokine, CCL3, in tumor tissues, and CTX-mediated tumor regression was attenuated in mice deficient in CCR5, the receptor for this chemokine. Consistently, less CTX-induced accumulation of intratumoral LAMP1/CD107a-expressing CD4(+) T cells was observed in mice receiving splenocytes derived from CCR5-deficient mice than in those receiving splenocytes derived from WT mice. Thus, CTX induces the expression of CCL3, which induces the intratumoral migration of CD4(+) T cells expressing cytotoxic molecules, leading to tumor eradication and subsequent specific tumor immunity.