Lactobacillus acidophilus Supplementation Exerts a Synergistic Effect on Tacrolimus Efficacy by Modulating Th17/Treg Balance in Lupus-Prone Mice via the SIGNR3 Pathway

ObjectiveTacrolimus (Tac) is an immunosuppressant used in the treatment of systemic lupus erythematosus (SLE); however, it induces T cell subset imbalances by reducing regulatory T (Treg) cells. Lactobacillus acidophilus (LA) is reported to have therapeutic efficacy in immune-mediated diseases via T cell regulation.MethodsThis study investigated whether a combination therapy of LA and Tac improves the therapeutic efficacy of Tac by modulating T cell subset populations in an animal model of SLE. Eight-week-old MRL/lpr mice were orally administered with 5 mg/kg of Tac and/or 50 mg/kg of LA daily for 8 weeks. Cecal microbiota compositions, serum autoantibodies levels, the degree of proteinuria, histological changes in the kidney, and populations of various T cell subsets in the spleen were analyzed.ResultsMice presented with significant gut dysbiosis, which were subsequently recovered by the combination treatment of Tac and LA. Double negative T cells in the peripheral blood and spleens of MRL/lpr mice were significantly decreased by the combination therapy. The combination treatment reduced serum levels of anti-dsDNA antibodies and Immunoglobulin G2a, and renal pathology scores were also markedly alleviated. The combination therapy induced Treg cells and decreased T helper 17 (Th17) cells both in vitro and in vivo. In vitro treatment with LA induced the production of indoleamine-2,3-dioxygenase, programmed death-ligand 1, and interleukin-10 via the specific intracellular adhesion molecule-3 grabbing non-integrin homolog-related 3 receptor signals.ConclusionThe present findings indicate that LA augments the therapeutic effect of Tac and modulates Th17/Treg balance in a murine model of SLE.

GITR Promotes the Polarization of TFH-Like Cells in Helicobacter pylori-Positive Gastritis

Gastric CD4+T cells contribute to Helicobacter pylori (H. pylori)-induced gastritis by amplifying mucosal inflammation and exacerbating mucosal injuries. However, the pathogenic CD4+ T cell subset involved in gastritis and the potential regulators are still unclear. Here we identified an IL-21-producing gastric CD4+T cell subset, which exhibited tissue-resident CXCR5−BTLA−PD-1hi TFH-like phenotype in H. pylori-positive gastritis patients. Meanwhile, we identified glucocorticoid-induced tumor necrosis factor receptor (GITR) as an important regulator to facilitate IL-21 production by CD4+T cells and accelerate mucosal inflammation in gastritis patients with H. pylori infection. Moreover, GITR expression was increased in gastric CD4+T cells of gastritis patients compared to healthy controls, along with the upregulated expression of its ligand GITRL in mucosal macrophages (Mϕ) of gastritis patients. Further observations showed that the activation of GITR/GITRL signal promoted the IL-21 production of CD4+T cells via the STAT3 pathway. Besides this, IL-21 from CD4+T cells induced the proliferation of B cell and promoted the production of inflammatory cytokines IL-1β and IL-6 and chemokines MIP-3α and CCL-25 as well as matrix metalloproteinase (MMP)-3 and MMP-9 by human gastric epithelial cells, suggesting the facilitating effect of IL-21-producing CD4+T cells on mucosal inflammation and injuries. Taking these data together, we revealed that GITR/GITRL signal promoted the polarization of mucosal IL-21-producing CD4+T cells in H. pylori-positive gastritis, which may provide therapeutic strategies for the clinical treatment of H. pylori-induced gastritis.

Application of Immunohistochemistry to Monitor the CD3+T Cell Subset Counts in Patients with Sepsis

[Objective]: To evaluate the application significance of Immunohistochemistry for monitoring peripheral blood CD3 + T cell subset (CD3+/CD3 + CD4+/CD3 + CD8+) counts in patients with sepsis.[Methods]: Two peripheral blood samples of 117 patients with sepsis on the first day of admission (D1) and 20 healthy control subjects were collected, and two peripheral blood samples of 20 patients with sepsis on the fourth day of admission (D4) were randomly collected and used to detect the lymphocyte counts of routine blood tests and CD3 + T cell subset count by Immunohistochemistry; the lymphocyte count levels between the sepsis group and the healthy control group were compared, and the correlation between the two in the same group were analyzed.[Results]:lymphocyte counts by routine blood tests and CD3 + T cell subset counts of patients with sepsis were significantly lower than those in healthy control subjects (P < 0.01). In the surviving group, the mean values of D4 CD3 + T cell subset counts increased significantly compared with D1, while the nonsurviving group did not rebound significantly; There was a significant positive correlation between lymphocyte counts by routine blood tests and CD3 + T lymphocyte subset counts in patients with sepsis and the healthy control subjects. (P < 0.01).[Conclusion]: Detection of CD3 + T cell subset counts by immunohistochemical method can reflect the cellular immune status of patients at a given time, thus it can be used as one of the immune monitoring methods in patients with sepsis.

Critical role of the CD44lowCD62Llow CD8+ T cell subset in restoring antitumor immunity in aged mice

CD8+ T cells play a central role in antitumor immune responses that kill cancer cells directly. In aged individuals, CD8+ T cell immunity is strongly suppressed, which is associated with cancer and other age-related diseases. The mechanism underlying this age-related decrease in immune function remains largely unknown. This study investigated the role of T cell function in age-related unresponsiveness to PD-1 blockade cancer therapy. We found inefficient generation of CD44lowCD62Llow CD8+ T cell subset (P4) in draining lymph nodes of tumor-bearing aged mice. In vitro stimulation of naive CD8+ T cells first generated P4 cells, followed by effector/memory T cells. The P4 cells contained a unique set of genes related to enzymes involved in one-carbon (1C) metabolism, which is critical to antigen-specific T cell activation and mitochondrial function. Consistent with this finding, 1C-metabolism–related gene expression and mitochondrial respiration were down-regulated in aged CD8+ T cells compared with young CD8+ T cells. In aged OVA-specific T cell receptor (TCR) transgenic mice, ZAP-70 was not activated, even after inoculation with OVA-expressing tumor cells. The attenuation of TCR signaling appeared to be due to elevated expression of CD45RB phosphatase in aged CD8+ T cells. Surprisingly, strong stimulation by nonself cell injection into aged PD-1–deficient mice restored normal levels of CD45RB and ameliorated the emergence of P4 cells and 1C metabolic enzyme expression in CD8+ T cells, and antitumor activity. These findings indicate that impaired induction of the P4 subset may be responsible for the age-related resistance to PD-1 blockade, which can be rescued by strong TCR stimulation.

CMV exposure drives long-term CD57+ CD4 memory T cell inflation following allogeneic stem cell transplant

Donor and recipient cytomegalovirus (CMV) serostatus correlate with transplant related mortality that is associated with reduced survival following allogeneic stem cell transplant (SCT). Prior epidemiologic studies have suggested that CMV seronegative recipients (R-) receiving a CMV seropositive graft (D+) experience inferior outcomes compared to other serostatus combinations, an observation that appears independent of viral reactivation. We therefore investigated the hypothesis that prior donor CMV exposure irreversibly modifies immunologic function after SCT. We identified a CD4+/CD57+/CD27- T cell subset that was differentially expressed between D+ and D- transplants and validated results with 120 patient samples. This T cell subset represents an average of 2.9% (D-/R-), 18% (D-/R+), 12% (D+/R-), and 19.6% (D+/R+) (p&lt;0.0001) of the total CD4+ T cell compartment and stably persists for at least several years post-SCT. Even in the absence of CMV reactivation post-SCT, D+/R- transplants displayed a significant enrichment of these cells compared to D-/R- transplants (p=0.0078). These are effector memory cells (CCR7-/ CD45RA+/-) that express T-bet, EOMES, granzyme B, secrete Th1 cytokines, and are enriched in CMV-specific T cells. These cells are associated with decreased T cell receptor diversity (p&lt;0.0001) and reduced proportions of major histocompatibility class II expressing classical monocytes (p&lt;0.0001), myeloid (p=0.024), and plasmacytoid dendritic cells (p=0.0014). These data describe a highly expanded CD4+ T cell population and putative mechanisms by which prior donor or recipient CMV exposure may create a lasting immunologic imprint following SCT, providing a rationale for using D- grafts for R- transplant recipients.

Single cell sequencing reveals expanded cytotoxic CD4+ T cells and two states of peripheral helper T cells in synovial fluid of ACPA+ RA patients

Rheumatoid arthritis is an autoimmune disease affecting the synovial joints where different subsets of CD4+ T cells are suspected to play a pathogenic role. So far, our understanding of the contribution of cytotoxic CD4+ T cells is incomplete, particularly in the context of the recently described peripheral helper T-cell subset (TPH). Here, using single cell sequencing and multi-parameter flow cytometry, we show that cytotoxic CD4+ T cells are enriched in synovial fluid of anti-citrullinated peptides antibody (ACPA)-positive RA patients. We identify two distinct TPH states differentially characterized by the expression of CXCL13 and PRDM1, respectively. Our data reveal that the adhesion G-Protein Coupled Receptor 56 (GPR56), a marker of circulating cytotoxic cells, delineates the synovial TPH CD4+ T-cell subset. At the site of inflammation, GPR56+CD4+ T cells expressed the tissue-resident memory markers LAG-3, CXCR6 and CD69. Further, TCR clonality analysis revealed that most expanded clones in SF are contained within the cytotoxic and the CXCL13+ TPH CD4+ T-cell populations. Finally, the detection of common TCRs between the two TPH and cytotoxic CD4+ T-cell clusters suggest a shared differentiation. Our study provides comprehensive immunoprofiling of the heterogenous T-cell subsets at the site of inflammation in ACPA+ RA and suggests GPR56 as a therapeutic target to modulate TPH cells and cytotoxic CD4+ T cell function