Selective expression of the Ly-6C.2 epitope on Lyt-2+ T cells that can develop in the absence of thymic influence.

The present study focused on attempts to correlate the expression of T cell differentiation antigens and development. A series of mAb was developed that recognized an Ly-6.2-linked Ag, Ly-6C.2. These mAb reacted with a subset of peripheral Lyt-2+ T lymphocytes but not Lyt-2+ thymocytes. Functional analysis of the Lyt-2+, Ly-6C.2- and Lyt-2+, Ly-6C.2+ subsets demonstrated that both cell types responded in class I and class II allogeneic MLC as well as in virus-specific cell-mediated cytolysis assay, although precursor frequency analysis suggested that the majority of precursor CTL were Ly-6C.2+. The marker did not appear to represent an activation Ag because Ly-6C.2-, Lyt-2+ precursor CTL generated Ly-6C.2-, Lyt-2+ CTL. Finally, virtually all splenic Lyt-2+ T cells from athymic (nu/nu) mice were Ly-6C.2+ whereas all thymic CTL were Ly-6C.2-. These results suggested that Ly-6C.2+, Lyt-2+ T cells may represent a distinct lineage of Lyt-2+ T cells that can develop in the absence of thymic influence.