Ley Klaus
Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA 92037, USA.
F1000Res. 2014 Feb 5;3:37. doi: 10.12688/f1000research.3-37.v2. eCollection 2014.
The second touch hypothesis states that T cell activation, proliferation, induction of homing receptors and polarization are distinguishable and, at least in part, sequential. The second touch hypothesis maintains that full T cell polarization requires T cell interaction with antigen-presenting cells (DCs, macrophages, B cells and certain activated stromal cells) in the non-lymphoid tissue where the antigen resides. Upon initial antigen encounter in peripheral lymph nodes (PLN), T cells become activated, proliferate and express homing receptors that enable them to recirculate to the (inflamed) tissue that contains the antigen. Differentiation into the T helper lineages Th1, Th2, Th17 and induced regulatory T cells (iTreg) requires additional antigen presentation by tissue macrophages and other antigen presenting cells (APCs) in the inflamed tissue. Here, I present a conceptual framework for the importance of peripheral (non-lymphoid) antigen presentation to antigen-experienced T cells.
二次接触假说认为，T细胞的激活、增殖、归巢受体的诱导和极化是可区分的，并且至少部分是顺序发生的。二次接触假说坚持认为，T细胞的完全极化需要T细胞与抗原所在的非淋巴组织中的抗原呈递细胞（树突状细胞、巨噬细胞、B细胞和某些活化的基质细胞）相互作用。在外周淋巴结（PLN）初次接触抗原时，T细胞被激活、增殖并表达归巢受体，使它们能够再循环到含有抗原的（炎症）组织。分化为辅助性T细胞谱系Th1、Th2、Th17和诱导性调节性T细胞（iTreg）需要炎症组织中的组织巨噬细胞和其他抗原呈递细胞（APC）进行额外的抗原呈递。在此，我提出了一个概念框架，阐述外周（非淋巴）抗原呈递对抗原致敏T细胞的重要性。
