Early events in T cell development
T cells constitute a heterogenous population of lymphocytes. Their unifying property is that they express surface bound antigen-receptors, called T cell receptors (TCRs). The TCR is a heterodimer composed of either TCRalpha and beta chain proteins (alphabeta TCR) or gamma and delta chain proteins (gammadelta TCR). Depending on which TCR isotype that is expressed, the T cells are divided into alpha