Presence of murine fetal liver cells capable of being induced to differentiate in vitro into T cell receptor-positive cells.

Abstract

Mouse fetal liver cells were analyzed for the surface expression of T cell markers. Fetal liver cells prepared from mouse embryos at 14.5 days of gestation contained a small number of CD4+ cells (1.4%), but virtually no cells positive for any other T cell markers such as CD8, CD3 and T cell receptor (TcR). When a fetal liver cell suspension prepared from BALB/c(male) x AKR(female) F1 embryos at 14.5 days of gestation was cultured in medium supplemented with culture supernatants of both WEHI-3 and concanavalin A-stimulated rat spleen cells, TcR alpha beta+ and CD4+ cells were generated, whereas CD8+ and TcR gamma delta+ cells were hardly detectable. Most of TcR alpha beta+ and CD4+ cells were H-2d+, thus clearly showing their fetal origin. Treatment with anti-CD4, anti-CD3 or anti-TcR alpha beta antibodies plus complement or electronic sorting to remove cells expressing these markers failed to inhibit the generation of T cell marker-positive cells following culture in vitro. On the other hand, depletion of Thy-1.2+ cells reduced their generation. These findings indicate the presence of some progenitor T cells in fetal liver with the Thy-1+, CD3-, CD4-, CD8-, TcR- phenotype, which can be induced to differentiate into TcR alpha beta+ cells in the presence of specific humoral supplements without the influence of the thymus.