Murine female reproductive tract intraepithelial lymphocytes display selection characteristics distinct from both peripheral and other mucosal T cells

Despite immense effort, the development of vaccines effective at mucosal si tes has proceeded at a faltering pace. Efforts concentrating on humoral imm unity but neglecting cellular immunity may be misdirected by ignoring many viral mucosal pathogens. Improved understanding of the development and main tenance of lymphocytes populating the reproductive tract (rtIELs) may infor m advances in vaccination strategies for sexually transmitted diseases. Rec ent studies highlight tissue-specific differences in the development of muc osal immunity and suggest that the local milieu may play a role in selectio n, maintenance and function of resident lymphocytes. Here, we describe MHC class I and thymus dependence of subpopulations of rtIELs. TCR alpha beta CD8 alpha beta + T cells in the periphery, intestine, and female reproduct ive tract are all developmentally dependent on classical class I MHC and th e thymus. TCR alpha beta + CD8 alpha alpha + are absent from the periphery and the rtIELs, but are present and classical MHC class I-independent, in t he intestine. In contrast to intestinal TCR gamma delta + cells, TCR gamma delta + rtIELs are CD8 negative and thymus dependent. In contrast to periph eral TCR gamma delta + cells, murine TCR gamma delta + rtIELs express not a diverse array of V delta genes, but rather, a canonical V delta1. In summa ry, lymphocytes isolated from the murine female reproductive tract have cha racteristics distinct from both peripheral T cells and those found at other mucosal sites. Therefore, for the purpose of vaccination strategies, the f emale reproductive tract should be regarded neither as peripheral nor mucos al, but rather as a tissue with distinctive immunological characteristics. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.