UNASSIGNED: Tuberculosis (TB) persists as a global health challenge, with its treatment hampered by the side effects of long-term combination drug therapies and the growing issue of drug resistance. Therefore, the development of novel therapeutic strategies is critical. This study focuses on the role of immune checkpoint molecules (ICs) and functions of CD8+ T cells in the search for new potential targets against TB.
UNASSIGNED: We conducted differential expression genes analysis and CD8+ T cell functional gene analysis on 92 TB samples and 61 healthy individual (HI) samples from TB database GSE83456, which contains data on 34,603 genes. The GSE54992 dataset was used to validated the findings. Additionally, a cluster analysis on single-cell data from primates infected with mycobacterium tuberculosis and those vaccinated with BCG was performed.
UNASSIGNED: The overexpression of LAG-3 gene was found as a potentially important characteristic of both pulmonary TB (PTB) and extrapulmonary TB (EPTB). Further correlation analysis showed that LAG-3 gene was correlated with GZMB, perforin, IL-2 and IL-12. A significant temporal and spatial variation in LAG-3 expression was observed in T cells and macrophages during TB infection and after BCG vaccination.
UNASSIGNED: LAG-3 was overexpressed in TB samples. Targeting LAG-3 may represent a potential therapeutic target for tuberculosis.

The key role of tissue-resident memory T (TRM) cells in the immune regulation of hepatocellular carcinoma (HCC) has been investigated and reported, but the regulatory mechanism of tumor microenvironment on TRM cells is still unclear. Lymphocyte activating gene 3 (LAG-3) is a promising next-generation immune checkpoint that is continuously expressed due to persistent antigen exposure in the tumor microenvironment. Fibrinogen-like protein 1 (FGL1) is a classical ligand of LAG-3 and can promote T cell exhaustion in tumors. Here, we excavated the effect of FGL1-LAG3 regulatory axis on TRM cells in HCC.
The function and phenotype of intrahepatic CD8+ TRM cells in 35 HCC patients were analyzed using multicolor flow cytometry. Using a tissue microarray of 80 HCC patients, we performed the prognosis analysis. Moreover, we investigated the suppressive effect of FGL1 on CD8+ TRM cells both in in vitro induction model and in vivo orthotopic HCC mouse model.
There was an increase in LAG3 expression in CD8+ TRM cells in end-stage HCC; moreover, FGL1 levels were negatively correlated with CD103 expression and related to poor outcomes in HCC. Patients with high CD8+ TRM cell proportions have better outcomes, and FGL1-LAG3 binding could lead to the exhaustion of CD8+ TRM cells in tumors, indicating its potential as a target for immune checkpoint therapy of HCC. Increased FGL1 expression in HCC may result in CD8+ TRM cell exhaustion, causing tumor immune escape.
We identified CD8+TRM cells as a potential immunotherapeutic target and reported the effect of FGL1-LAG3 binding on CD8+ TRM cell function in HCC.

Introduction: Therapeutic targeting of inhibitors of the immune response has reached the clinical setting. Inhibitors of the novel receptor LAG3, which negatively regulates T-cell activation, are under investigation. Here we explore the presence and prognostic role of LAG3 in cancer. Methods: A systematic search of electronic databases identified publications exploring the effect of LAG3 on overall survival (OS) and (for early-stage cancers) disease-free survival (DFS). Hazard ratios (HR) were pooled in a meta-analysis using generic inverse-variance and random effect modeling. Subgroup analyses were conducted based on disease site and tumor type. Results: Fifteen studies met the inclusion criteria. LAG3 was associated with better overall survival [HR 0.81, 95% confidence interval (CI) 0.66-0.99; P = 0.04], with subgroup analysis showing no significant differences between disease-site subgroups. The beneficial effect of LAG3 on OS was of greater magnitude in early-stage malignancies (HR 0.73, 95% CI 0.60-0.88) than in the metastatic setting (HR 1.20, 95% CI 0.70-2.05), but this difference was not statistically significant (subgroup difference p = 0.18). LAG3 did not have a significant association with DFS [HR 1.02, 95% confidence interval (CI) 0.77-1.37; P = 0.87], with subgroup analysis showing worse DFS in patients with lymphoma and improved DFS in those with breast cancer. Conclusions: High expression of LAG3 is associated with favorable overall survival in several solid tumors. A trend toward an association in early-stage disease suggests the importance of immune surveillance in this setting.

To cope with immune responses, tumour cells implement elaborate strategies such as adaptive resistance and induction of T-cell exhaustion. T-cell exhaustion has been identified as a state of hyporesponsiveness that arises under continuous antigenic stimulus. Nevertheless, contribution of co-stimulatory molecules to T-cell exhaustion in cancer remains to be better defined. This study explores the role of myeloid leukaemia-derived co-stimulatory signals on CD4+ T helper (Th) cell exhaustion, which may limit anti-tumour immunity. Here, CD86 and inducible T-cell co-stimulator ligand (ICOS-LG) co-stimulatory molecules that are found on myeloid leukaemia cells supported Th cell activation and proliferation. However, under continuous stimulation, T cells co-cultured with leukaemia cells, but not with peripheral blood monocytes, became functionally exhausted. These in vitro-generated exhausted Th cells were defined by up-regulation of programmed cell death 1 (PD-1), cytotoxic T-lymphocyte antigen 4 (CTLA-4), lymphocyte activation gene 3 (LAG3) and T-cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) inhibitory receptors. They were reluctant to proliferate upon re-stimulation and produced reduced amounts of interleukin-2 (IL-2), tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Nonetheless, IL-2 supplementation restored the proliferation capacity of the exhausted Th cells. When the co-stimulation supplied by the myeloid leukaemia cells were blocked, the amount of exhausted Th cells was significantly decreased. Moreover, in the bone marrow aspirates from patients with acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS), a subpopulation of Th cells expressing PD-1, TIM-3 and/or LAG3 was identified together with CD86+ and/or ICOS-LG+ myeloid blasts. Collectively, co-stimulatory signals derived from myeloid leukaemia cells possess the capacity to facilitate functional exhaustion in Th cells.

BACKGROUND: The mechanisms contributing to clinical immune tolerance remain incompletely understood. This study provides evidence for specific immune mechanisms that are associated with a model of operationally defined clinical tolerance.
OBJECTIVE: Our overall objective was to study laboratory changes associated with clinical immune tolerance in antigen-induced T cells, basophils, and antibodies in subjects undergoing oral immunotherapy (OIT) for peanut allergy.
METHODS: In a phase 1 single-site study, we studied participants (n = 23) undergoing peanut OIT and compared them with age-matched allergic control subjects (n = 20) undergoing standard of care (abstaining from peanut) for 24 months. Participants were operationally defined as clinically immune tolerant (IT) if they had no detectable allergic reactions to a peanut oral food challenge after 3 months of therapy withdrawal (IT, n = 7), whereas those who had an allergic reaction were categorized as nontolerant (NT; n = 13).
RESULTS: Antibody and basophil activation measurements did not statistically differentiate between NT versus IT participants. However, T-cell function and demethylation of forkhead box protein 3 (FOXP3) CpG sites in antigen-induced regulatory T cells were significantly different between IT versus NT participants. When IT participants were withdrawn from peanut therapy for an additional 3 months (total of 6 months), only 3 participants remained classified as IT participants, and 4 participants regained sensitivity along with increased methylation of FOXP3 CpG sites in antigen-induced regulatory T cells.
CONCLUSIONS: In summary, modifications at the DNA level of antigen-induced T-cell subsets might be predictive of a state of operationally defined clinical immune tolerance during peanut OIT.