Dendritic cell expression of CD24 inhibits autoantigen-mediated deletion of T lymphocytes in the thymus (36.30)

Abstract Despite negative selection, significant numbers of autoreactive T cells can be easily detected and expanded even in normal individuals. While lack of self antigen expression has been largely attributed as a key factor, we have reported that CD24, a GPI-anchored glycoprotein, regulates thymic deletion of autoreactive T lymphocytes. CD24-deficient 2D2 TCR transgenic mice (2D2+CD24-/-), whose TCR recognize myelin antigen MOG, failed to generate functional 2D2 T cells. Here we further show that elimination of MOG antigen expression in 2D2+CD24-/- mice (through creation of 2D2+CD24-/-MOG-/- mice), completely restored thymic cellularity and function of 2D2 T cells. Restoration of CD24 expression on dendritic cells, but not on thymocytes also restored 2D2 T cell generation in 2D2+CD24-/- mice. Taken together, we propose that CD24 expression on dendritic cells inhibits autoantigen-mediated deletion of autoreactive thymocytes.