Effect of human thymic epithelial conditioned medium on in vitro and in vivo alloantigen-induced lymphocyte activation in the mouse

Abstract

Human thymic epithelial conditioned medium (HTECM), but not control conditioned media, has been shown previously to enhance the Con A and PHA responsiveness of human and mouse thymocytes and the PHA response of spleen cells. In this study we have demonstrated that HTECM increased the reactivity of mouse thymocytes in oneway mixed lymphocyte culture and in cell-mediated cytotoxicity, while no enhancing effects were observed with spleen cells. Incubation of mouse thymocytes with HTECM rendered the cells more reactive in in vivo graft versus host reactions. The findings indicate that HTECM, an in vitro produced factor of the human thymus, plays an important role in the induction of immunocompetence in thymocytes.