CD8+ T cells in fetal membranes display a unique phenotype, and their activation is involved in the pathophysiology of spontaneous preterm birth.

Preterm labor/birth is the leading cause of perinatal mortality and morbidity worldwide. Previous studies demonstrated that T cells were crucial for maintaining maternal-fetal immune tolerance during the first trimester of pregnancy; however, their phenotypes and functions in labor and delivery remain largely unknown. We recruited three cohorts of women at delivery for T-cell immunophenotyping in the placentas, fetal membranes, umbilical cord blood, and maternal peripheral blood. Our data showed a differential enrichment of T cells during the third trimester of human pregnancy, with CD4+ T cells being more observable within the umbilical cord blood, whereas CD8+ T cells became relatively more abundant in fetal membranes. CD4+ and CD8+ T cells derived from fetal membranes were dominated by effector memory T cells and exhibited extensive expression of activation markers but decreased expression of homing receptor. In comparison with term births, fetal membrane CD8+ T cells, especially the central memory subset, were significantly increased in frequency and showed more profound activation in spontaneous preterm birth patients. Finally, using an allogeneic mouse model, we found that T-cell-activation-induced preterm birth could be alleviated by the depletion of CD8+ T but not CD4+ T cells in vivo. Collectively, we showed that CD8+ T cells in fetal membranes displayed a unique phenotype, and their activation was involved in the pathophysiology of spontaneous preterm birth, which provides novel insights into the immune mechanisms of preterm birth and potential targets for the prevention of this syndrome. © 2023 The Pathological Society of Great Britain and Ireland.

Early-like differentiation status of systemic PD-1+CD8+ T cells predicts PD-1 blockade outcome in non-small cell lung cancer.

Objectives: Despite remarkable advances in the treatment of non-small cell lung cancer (NSCLC) with anti-programmed death (PD)-1 therapy; only a fraction of patients derives durable clinical benefit. In this study, we investigated whether the differentiation status of systemic CD8+ T cells predicts the outcome of PD-1 blockade in NSCLC. Methods: We carried out a prospective study on a total of 77 NSCLC patients receiving anti-PD-1 blockers, among which 47 patients were assigned as a discovery cohort and 30 patients as a validation cohort. Peripheral blood samples were obtained at baseline and upon multiple therapy cycles and analyzed by multi-parameter flow cytometry. Results: We found that a higher baseline ratio of PD-1+ early effector memory CD8+ T cells (CD28+CD27-CD45RO+, TEEM) to PD-1+ effector CD8+ T cells (CD28-CD27-CD45RO-, TE) delineated responders to PD-1 blockade from progressors and was associated with prolonged progression-free survival (PFS) and durable clinical benefit. Moreover, PD-1+CD8 TEEM cells exhibited early responses after anti-PD-1 therapy and was the major fraction of cycling PD-1+Ki67+CD8+ T cells to expand specifically with positive impact on PFS. Conclusion: These findings provide insights into how the baseline differentiation status of the peripheral immune system determines responses to PD-1-targeted therapies.

Restored and Enhanced Memory T Cell Immunity in Rheumatoid Arthritis After TNFα Blocker Treatment.

TNFα inhibitors have shaped the landscape of rheumatoid arthritis (RA) therapy with high clinical efficiency. However, their impact on T cell recall responses is not well-elucidated. We aimed to analyze the immune profiles of memory T cells in RA patients undergoing TNFα inhibitor Golimumab (GM) treatment. Frequencies of peripheral T cell subsets and cytokine expression profiles in memory T cells (TM) upon PMA/Ionomycine stimulation were determined by flow cytometry. Antigen-specific CD8 T cell immunity was analyzed through stimulating PBMCs with CMV-EBV-Flu (CEF) viral peptide pool and subsequent intracellular IFNγ staining. Both peripheral CD8 and CD4 T cells from GM treated patients had a shift pattern characterized by an enlarged effector TM and a reduced central TM cell population when compared to GM untreated group. An increase in the frequencies of TNFα+, IL-2+, and IL-17+ CD8 TM cells was observed whereas only TNFα+CD4 TM cells increased in GM treated patients. Moreover, GM treated patients contained more peripheral IFNγ-producing CD8 T cells specific to CEF viral peptides. Together, these results show a distinct T cell subset pattern and enhanced memory T cell immunity upon GM treatment, suggesting an immunoregulatory effect of TNF inhibitor Golimumab on peripheral memory T cell responses.

Deep Surveying of the Transcriptional and Alternative Splicing Signatures for Decidual CD8+ T Cells at the First Trimester of Human Healthy Pregnancy.

Decidual CD8+ (dCD8) T cells have been proposed to play important roles in immune protection against the invading pathogens and in tolerance toward the growing semi-allogeneic fetus during early pregnancy. However, their phenotypic and functional characteristics remain poorly defined. Here, we performed the first analysis of the transcriptional and alternative splicing (AS) signatures for human first-trimester dCD8 T cells using high-throughput mRNA sequencing. Our data revealed that dCD8 T cells have distinct transcriptional and AS landscapes when compared with their autologous peripheral blood CD8+ (pCD8) T counterparts. Furthermore, human dCD8 T cells were observed to contain CD8-Treg and effector-memory T-cell subsets, and display enhanced functionality in terms of degranulation and cytokine production on a per-cell basis. Additionally, we have identified the novel splice junctions that use a high ratio of the non-canonical splicing motif GC-AG and found that AS is not a major contributor to the gene expression-level changes between paired pCD8 and dCD8 T cells. Together, our findings not only provide a comprehensive framework of the transcriptional and AS landscapes but also reveal the functional feature of human dCD8 T cells, which are of great importance in understanding the biology of these cells and the physiology of human healthy pregnancy.

OVA12 promotes tumor growth by regulating p53 expression in human cancer cells.

Ovarian cancer-associated antigen 12 (OVA12) was first identified in an ovarian carcinoma complementary DNA (cDNA) expression library and has been shown to play an important role in tumor growth. Here, we found that overexpression of OVA12 accelerated tumor growth in different tumor cells, whereas OVA12 depletion was associated with the opposite effect. Moreover, knocking down OVA12 led to a significant increase in the protein levels of p53, and the overexpression of OVA12 significantly decreased endogenous p53 levels. In addition, OVA12 stimulated p53 polyubiquitination and degradation by the proteasome and promoted tumor growth at least partially through the p53 pathway. Taken together, these results indicate that OVA12 is a negative regulator of p53 and that inhibition of OVA12 expression might serve as a therapeutic target to restore tumor suppression.

Distinct Transcriptional and Alternative Splicing Signatures of Decidual CD4+ T Cells in Early Human Pregnancy.

Decidual CD4+ T (dCD4 T) cells are crucial for the maternal-fetal immune tolerance required for a healthy pregnancy outcome. However, their molecular and functional characteristics are not well elucidated. In this study, we performed the first analysis of transcriptional and alternative splicing (AS) landscapes for paired decidual and peripheral blood CD4+ T (pCD4 T) cells in human early pregnancy using high throughput mRNA sequencing. Our data showed that dCD4 T cells are endowed with a unique transcriptional signature when compared to pCD4 T cells: dCD4 T cells upregulate 1,695 genes enriched in immune system process whereas downregulate 1,011 genes mainly related to mRNA catabolic process and the ribosome. Moreover, dCD4 T cells were observed to be at M phase, and show increased activation, proliferation, and cytokine production, as well as display an effector-memory phenotype and a heterogenous nature containing Th1, Th17, and Treg cell subsets. However, dCD4 T cells undergo a comparable number of upregulated and downregulated AS events, both of which are enriched in the genes related to cellular metabolic process. And the changes at the AS event level do not reflect measurable differences at the gene expression level in dCD4 T cells. Collectively, our findings provide a comprehensive portrait of the unique transcriptional signature and AS profile of CD4+ T cells in human decidua and help us gain more understanding of the functional characteristic of these cells during early pregnancy.

Transcriptome Signatures Reveal Rapid Induction of Immune-Responsive Genes in Human Memory CD8(+) T Cells.

Memory T cells (TM) play a prominent role in protection and auto-immunity due to their ability to mount a more effective response than naïve T cells (TN). However, the molecular mechanisms underlying enhanced functionality of TM are not well defined, particularly in human TM. We examined the global gene expression profiles of human CD8(+) TN and TM before and after stimulation. There were 1,284, 1,373 and 1,629 differentially expressed genes between TN and TM at 0 hr, 4 hr and 24 hr after stimulation, respectively, with more genes expressed to higher levels in TM. Genes rapidly up-regulated in TN cells were largely involved in nitrogen, nucleoside and amino acid metabolisms. In contrast, those in CD8(+) TM were significantly enriched for immune-response-associated processes, including cytokine production, lymphocyte activation and chemotaxis. Multiple cytokines were rapidly up-regulated in TM cells, including effector cytokines known to be produced by CD8(+) T cells and important for their functions, as well as regulatory cytokines, both pro- and anti-inflammatory, that are not typically produced by CD8(+) T cells. These results provide new insights into molecular mechanisms that contribute to the enhanced functionality of human CD8(+) TM and their prominent role in protection and auto-immunity.

Construction of two Listeria ivanovii attenuated strains expressing Mycobacterium tuberculosis antigens for TB vaccine purposes.

Bacillus Calmette-Guerin (BCG) has failed in complete control of tuberculosis (TB), thus, novel tuberculosis vaccines are urgently needed. We have constructed several TB vaccine candidates, which are characterized by the use of Listeria ivanovii (LI) strain as an antigen delivery vector. Two L. ivanovii attenuated recombinant strains L. ivanovii△actAplcB-Rv0129c and L. ivanovii△actAplcB-Rv3875 were successfully screened. Results from genome PCR and sequencing showed that the Mycobacterium tuberculosis antigen gene cassette coding for Ag85C or ESAT-6 protein respectively had been integrated into LI genome downstream of mpl gene. Western blot confirmed the secretion of Ag85C or ESAT-6 protein from the recombinant LI strains. These two recombinant strains showed similar growth curves as wide type strain in vitro. In vivo, they transiently propagated in mice spleen and liver, and induced specific CD8(+) IFN-γ secretion. Therefore, in this paper, two novel LI attenuated strains expressing specific TB antigens were successfully constructed. The promising growth characteristics in mice immune system and the capability of induction of IFN-γ secretion make them of potential interest for development of TB vaccines.

Expression of porcine respiratory and reproductive syndrome virus membrane-associated proteins in Listeria ivanovii via a genome site-specific integration and expression system.

Listeria ivanovii (LI) possesses a facultative intracellular life cycle in macrophages and non-professional phagocytes thus making it a potential novel vaccine vector. We have developed a genome site-specific integration system as a universal tool for constructing the live LI-based vaccines. Using this system, the porcine reproductive and respiratory syndrome virus (PRRSV) orf5 and orf6 genes, coding for PRRSV membrane-associated protein GP5 and M, respectively, were integrated into the LI genome. Genome PCR and sequencing results showed that the orf5 or orf6 gene had been integrated into the LI genome downstream of orfXYZ or mpl gene. Western blot analysis of the non-secreted and secreted bacterial protein samples showed the expression and secretion of GP5 or M protein from the recombinant LI strains. The secretion of the heterologous proteins is a key step for bacterial vaccine vectors to deliver the antigens to the immune system to stimulate antigen-specific immune responses. Therefore, this integration system may be a potential tool for constructing novel vaccines using live LI as vector.

Long-term exposure to decabrominated diphenyl ether impairs CD8 T-cell function in adult mice.

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental pollutants that accumulate to high levels in human populations that are subject to occupational or regional industry exposure. PBDEs have been shown to affect human neuronal, endocrine and reproductive systems, but their effect on the immune system is not well understood. In this study, experimental adult mice were intragastrically administered 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) at doses of 8, 80 or 800 mg/kg of body weight (bw) at 2-day intervals. Our results showed that continuous exposure to BDE-209 resulted in high levels of BDE-209 in the plasma that approached the levels found in people who work in professions with high risks of PDBE exposure. Reduced leukocytes, decreased cytokine (IFN-γ, IL-2 and TNF-α) production and lower CD8 T-cell proliferation were observed in the mice exposed to BDE-209. Additionally, mice with long-term BDE-209 exposure had lower numbers of antigen-specific CD8 T cells after immunization with recombinant Listeria monocytogenes expressing ovalbumin (rLm-OVA) and the OVA-specific CD8 T cells had reduced functionality. Taken together, our study demonstrates that continuous BDE-209 exposure causes adverse effects on the number and functionality of immune cells in adult mice.

Investigation on antigen-specific T cell responses in type 2 diabetes mellitus patients / 中华内分泌代谢杂志

Objective To investigate the antigen-specific T cell functionality in type 2 diabetes mellitus patients. Methods Peripheral blood from 38 type 2 diabetes mellitus patients and 47 health controls (control group) have been collected. The proportions of CD4+and CD8+T cell as well as the ratio of CD4+/CD8+were monitored by flow cytometry. Meanwhile, antigen- nonspecific and specific Th1 responses were compared between two groups through detecting interferon (IFN)-γ, interleukin 2 (IL-2), and tumor necrosis factor (TNF)-α producing cells upon propylene glycol monomethyl ether acetate (PMA)/ionomycine and epstein-barr virus ( EBV) peptides stimulation, respectively followed by an intracellular cytokine staining. Results Compared to control group, the proportion of CD4+T cell and the ratio of CD4+/CD8+were significantly increased in type 2 diabetes mellitus group (P＜0.05) whereas CD8+T cells exhibited no significant difference between two groups. Antigen-nonspecific Th1 responses in type 2 diabetes mellitus patients were significantly decreased, demonstrated by lower percentages of IFN-γ, IL-2, and TNF-α producing CD4+T cells when compared to control group , while CD8+T cells in type 2 diabetes mellitus patients exhibited similar cytokine production patterns. However, when stimulated by EBV specific peptides, the percentages of IFN-γ, IL-2, and TNF-α producing CD8+T cells were significantly higher in type 2 diabetes mellitus patients than those in control group (P＜0.05). HbA1Cwas positively correlated with the percentage of EBV-specific TNF-α producing CD8+T cells (P＜0.05). Conclusion In type 2 diabetes mellitus, the secretion capacity of CD4+and CD8+T cell was significantly decreased and the antigen-specific responses represent the presence of an abnormal activated status, which indicates that chronic hyperglycemia may damage T cells function and aggravate chronic inflammation.