(Not) Home alone: Antigen presenting cell – T Cell communication in barrier tissues

Abstract

Priming of T cells by antigen presenting cells (APCs) is essential for T cell fate decisions, enabling T cells to migrate to specific tissues to exert their effector functions. Previously, these interactions were mainly explored using blood-derived cells or animal models. With great advances in single cell RNA-sequencing techniques enabling analysis of tissue-derived cells, it has become clear that subsets of APCs are responsible for priming and modulating heterogeneous T cell effector responses in different tissues. This composition of APCs and T cells in tissues is essential for maintaining homeostasis and is known to be skewed in infection and inflammation, leading to pathological T cell responses. This review highlights the commonalities and differences of T cell priming and subsequent effector function in multiple barrier tissues such as the skin, intestine and female reproductive tract. Further, we provide an overview of how this process is altered during tissue-specific infections which are known to cause chronic inflammation and how this knowledge could be harnessed to modify T cell responses in barrier tissue.

Matrix alignment and density modulate YAP-mediated T-cell immune suppression

“…We hypothesize that this observation reflects the immunological requirement wherein resting T-cells rapidly migrate to survey antigen-presenting cells (APCs) in peripheral tissues. Activated T-cells subsequently reduce their migration to remain in inflamed tissues, which facilitates their proper activation and subsequent differentiation into effector or memory Tcell subsets [4][5][6].…”

“…This journey is likely underpinned by the principle of cellular mechanotransduction [1][2][3], a process that enables T-cells to fine-tune their behavior, optimizing immunological responses and operational efficacy. Such adaptability is underscored by observations that T-cells alter their migration patterns in response to the diverse mechanical cues encountered across different tissue landscapes [4][5][6]. Although the role of cytokines in modulating immune responses has been extensively documented, the influence of the biophysical properties of tissues on T-cell functionality has not been fully explored; however, a comprehensive understanding of T-cell behavior, particularly under disease conditions, is imperative.…”

Functional heterogeneity of human skin‐resident memory T cells in health and disease

“…92,93 Cross talk of T RM with antigen presenting cells and stromal cells is extensively reviewed elsewhere. 94 In steady state, the percentage of skin T RM proliferating within a week, detected as bromodeoxyuridine (BrDU)-uptaking cells, is below 5%. 1 This number is lower than that of T RM in other tissues, for example the brain parenchyma, which suggests superior survival capacity of individual skin T RM in a resting state due to adaptation to local nutrient availability.…”

“…Besides meeting metabolic requirements, the skin environment contains a plethora of locally residing antigen presenting cells producing chemokines and cytokines including IL‐7, IL‐15, and TGF‐β for T RM maintenance 92,93 . Cross talk of T RM with antigen presenting cells and stromal cells is extensively reviewed elsewhere 94 …”

“… 92 , 93 Cross talk of T RM with antigen presenting cells and stromal cells is extensively reviewed elsewhere. 94 …”