Expression and function of c-Met, a receptor for hepatocyte growth factor, during T-cell development.

The c-Met oncoprotein is a cell-surface receptor for hepatocyte growth factor (HGF). Signals through HGF and c-Met have been appreciated for their crucial roles in the development of many cell types, including liver cells. The present study examined whether c-Met is expressed in the thymus and whether c-Met/HGF signals can regulate T-cell development in the thymus. We have found that mRNA transcripts encoding c-Met are expressed in mouse thymus. The c-Met transcripts were expressed at higher levels in fetal and neonatal thymus than in adult thymus, and were mostly expressed by lymphoid cells rather than by stromal cells. Interestingly, the addition of HGF to fetal thymus organ cultures increased the generation of mature T cells expressing high levels of T-cell antigen receptors. These results indicate that c-Met is expressed in the thymus during early ontogeny, and that c-Met/HGF signals can promote T-cell development.