JAK/STAT signalling is a key regulator of CD4 + T cell activation and function, influencing immune responses during infection. Ruxolitinib, a JAK1/2 inhibitor, transiently suppresses JAK/STAT signalling, but its impact on antigen-specific CD4 + T cell responses in malaria is unknown. In this study, we assessed the effects of ruxolitinib on CD4 + T cell cytokine signalling and immune responses using a controlled human malaria infection model. Whole blood was stimulated with IFNβ, IL-2, or PMA/Ionomycin, and phosphorylated STAT (pSTAT) expression was analysed. AIM assays and CyTOF were used to examine antigen-specific and memory CD4 + T cell responses during primary and secondary infections. Ruxolitinib significantly reduced pSTAT1, pSTAT3, and pSTAT5 expression in CD4 + T cells during treatment but did not impair antigen-specific responses. Instead, it enhanced recall immunity during secondary infection, particularly in AIM + T follicular helper (Tfh), T helper (Th)1, and type 1 regulatory (Tr1) cell subsets. Furthermore, increased frequencies of circulating Th1 and Tfh cells, but not Tr1 cells correlated with improved parasite control. These findings suggest that transient JAK inhibition modulates immune responses in a manner that could be leveraged as a host-directed therapy for malaria. Further research is needed to explore its potential applications in immune modulation for infectious diseases.

ABSTRACT Background Immunotherapy has significantly improved outcomes for cancer patients; however, its clinical benefits vary among patients and its effectiveness across breast cancer subtypes remains uncertain. To enhance its efficacy, it is important to gain more insight into tumor-intrinsic immunomodulatory factors that could be used as therapeutic targets. We previously identified Lactate Dehydrogenase C (LDHC) to be a promising anti-cancer target due to its role in regulating cancer cell genomic integrity. In this study, we investigated the effects of tumor LDHC expression on immune responses. Methods TIMER AND TIDE deconvolution methods were used to investigate the relationship between tumor LDHC expression, immune cell infiltration and T cell dysfunction. Multiplex cytokine assays and flow cytometry analyses of breast cancer cell monocultures, and direct and indirect cancer cell-immune cell co-culture models were performed to assess the effect of LDHC knockdown on the secretion of inflammatory mediators and the expression of immune checkpoint molecules. T cell activity was determined by IFN-γ ELISPot assays and 7-AAD viability flow cytometry of cancer cells in direct co-culture. Results TIMER and TIDE analyses revealed that tumor LDHC expression is associated with T cell dysfunction in breast cancer and worse post-immunotherapy survival in melanoma. Depletion of LDHC in three breast cancer cell lines (MDA-MB-468, BT-549, HCC-1954) enhanced T cell activation and cytolytic function (4-hour direct co-culture). Analysis of cancer cell monocultures revealed an increase in secreted pro-inflammatory cytokines (IFN-γ, GM- CSF, MCP-1, CXCL1), a decrease in immunosuppressive factors (IL-6, Gal-9) and a reduction in tumor cell surface PD-L1 expression following LDHC knockdown. Using 72-hour direct co- cultures with LDHC-silenced cancer cells, we observed a decrease in tumor-promoting cytokines (IL-1β, IL-4 and IL-6) and an increase in the tumor-inhibiting cytokine CXCL1. Furthermore, LDHC knockdown reduced the number of CD8+ T cells expressing PD-1 and CTLA-4, as well as the cell surface expression of CTLA-4, TIGIT, TIM3, and VISTA. Conclusions Our findings suggest that targeting LDHC may improve anti-tumor immune responses by modulating the secretion of pro- and anti-tumorigenic cytokines and impairing immune checkpoint signaling. Further studies are needed to elucidate the molecular mechanisms by which LDHC modulates these responses in breast cancer.

Tumor microbiota can produce active metabolites that affect cancer and immune cell signaling, metabolism, and proliferation. Here, we explore tumor and gut microbiome features that affect chemoradiation response in patients with cervical cancer using a combined approach of deep microbiome sequencing, targeted bacterial culture, and in vitro assays. We identify that an obligate L-lactate-producing lactic acid bacterium found in tumors, Lactobacillus iners, is associated with decreased survival in patients, induces chemotherapy and radiation resistance in cervical cancer cells, and leads to metabolic rewiring, or alterations in multiple metabolic pathways, in tumors. Genomically similar L-lactate-producing lactic acid bacteria commensal to other body sites are also significantly associated with survival in colorectal, lung, head and neck, and skin cancers. Our findings demonstrate that lactic acid bacteria in the tumor microenvironment can alter tumor metabolism and lactate signaling pathways, causing therapeutic resistance. Lactic acid bacteria could be promising therapeutic targets across cancer types.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

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.
Copyright © 2023 Yang, Qian, Zhao, Huang, Chen, Gong, Ji, Wang, Xia, You, Zhang and Chen.

Neoadjuvant ipilimumab + nivolumab (Ipi+Nivo) and nivolumab + chemotherapy (Nivo+CT) induce greater pathologic response rates than CT alone in patients with operable non-small cell lung cancer (NSCLC). The impact of adding ipilimumab to neoadjuvant Nivo+CT is unknown. Here we report the results and correlates of two arms of the phase 2 platform NEOSTAR trial testing neoadjuvant Nivo+CT and Ipi+Nivo+CT with major pathologic response (MPR) as the primary endpoint. MPR rates were 32.1% (7/22, 80% confidence interval (CI) 18.7-43.1%) in the Nivo+CT arm and 50% (11/22, 80% CI 34.6-61.1%) in the Ipi+Nivo+CT arm; the primary endpoint was met in both arms. In patients without known tumor EGFR/ALK alterations, MPR rates were 41.2% (7/17) and 62.5% (10/16) in the Nivo+CT and Ipi+Nivo+CT groups, respectively. No new safety signals were observed in either arm. Single-cell sequencing and multi-platform immune profiling (exploratory endpoints) underscored immune cell populations and phenotypes, including effector memory CD8+ T, B and myeloid cells and markers of tertiary lymphoid structures, that were preferentially increased in the Ipi+Nivo+CT cohort. Baseline fecal microbiota in patients with MPR were enriched with beneficial taxa, such as Akkermansia, and displayed reduced abundance of pro-inflammatory and pathogenic microbes. Neoadjuvant Ipi+Nivo+CT enhances pathologic responses and warrants further study in operable NSCLC. (ClinicalTrials.gov registration: NCT03158129 .).
© 2023. The Author(s).