Biology subjects

Morales Mendez, A.

Publications and source records attributed to Morales Mendez, A..

3 recordsLinked to original sources

bioRxiv2026

Distinct activation programs in naive and memory CD8 T cells govern stemness and effector persistence of their progeny

Infection- and vaccination-induced memory CD8+ T cells provide protection upon subsequent exposure to cognate antigen through their increased abundance and robust per-cell responses. However, how prior antigen experience alters T-cell activation programs remains poorly understood. We longitudinally profiled gene expression in naive, central memory, and effector memory CD8+ T cells in response to cognate antigen across multiple models of acute infection. Naive T cells engaged TOX- and TCF7-centered programs and generated early stem-like central memory precursors. Their initially slow proliferation was followed by rapid expansion and the production of large numbers of short-lived effector cells. Central memory T cells rapidly triggered effector and proliferation programs while maintaining a smaller self-renewing population. Effector memory T cells expanded poorly and generated almost exclusively effector progeny. Effector progeny derived from both memory subsets survived contraction more efficiently than naive T-cell-derived progeny and established persistent effector memory populations. These data show that prior antigen experience does not simply accelerate CD8+ T-cell activation but redirects cell-intrinsic programs that shape progeny fate and persistence. These distinct programs may reflect adaptation to primary versus repeated antigen exposure and suggest that infection and vaccination history can shape the balance between stem-like memory and persistent effector populations.

immunology↗

bioRxiv2026

T cells restrain inflammation driven by TNF-induced cell death

TNF is a potent proinflammatory cytokine that can induce cell death by activating the kinase RIPK1. The adaptor proteins TANK and AZI2 protect against cell death by recruiting TBK1 to the TNF receptor signaling complex, thereby inhibiting RIPK1. While deficiency of either adaptor alone is well tolerated, combined loss of TANK and AZI2 results in partial embryonic lethality and severe TNF- and RIPK1-driven autoinflammation. Here, we show that TANK/AZI2-deficient mice exhibit a striking expansion of regulatory T cells (Tregs), most of which display an effector phenotype with high expression of immunosuppressive genes. Although thymic Treg generation is modestly increased, Tregs arise predominantly in the periphery through a largely cell-intrinsic mechanism. The marked accumulation of effector Tregs suggested that the T-cell compartment may limit TNF-driven pathology in this model. Supporting this, T cell ablation in TANK/AZI2-deficient mice markedly exacerbates disease progression and enhances TNF-driven, RIPK1-mediated inflammation. Similarly, T cells protect against acute TNF-induced systemic inflammatory response syndrome by limiting RIPK1-mediated cell death. Together, our findings identify TANK and AZI2 as negative regulators of Treg formation, demonstrate that T cells restrain TNF-driven inflammation by limiting RIPK1-dependent cell death, and suggest that this protective effect is mediated primarily by Tregs.

immunology↗

bioRxiv2025

LCK deficiency in CD8 T cells leads to reduced proliferation and increased effector T-cell formation in mice

LCK is an SRC-family kinase that mediates the initial steps in T-cell antigen receptor signaling and governs positive and negative selection during thymocyte development. While its developmental role is well established, its functions in peripheral T-cell responses remain poorly defined. Here, we investigated the responses of wild-type and LCK-deficient TCR-transgenic OT-I T cells across two infection models and an autoimmune diabetes model. LCK-deficient T cells exhibited reduced antigen-induced proliferation but, paradoxically, displayed enhanced effector differentiation in vivo. This phenotype likely reflects dysregulation of specific TCR signaling pathways, as LCK was more critical for ERK and NFAT activation than for NF{kappa}B, AP-1, or AKT/mTOR signaling. T cells deficient in a related kinase FYN also showed a slight increase in effector cell formation, suggesting that effector differentiation is regulated by their combined activity rather than distinct non-redundant roles. Our results reveal that LCK has two intrinsic roles in T-cell responses - promoting proliferation while restraining effector differentiation. These findings provide new insight into the molecular mechanisms of T-cell activation in vivo with implications for understanding the pathophysiology of LCK deficiency in humans and optimizing adoptive T-cell therapies.

immunology↗