[Early T cell development in gene-targeted mutant mice].

Early intrathymic T cell development is highly coordinated and controlled by the interaction of a variety of molecules. The development of gene targeting technology provided a valuable tool to study the function of these molecules in vivo. The analysis of TCR and CD3 gene targeted mice indicated that CD44-CD25+ is a control point in early T cell development. At this stage, the expression of pre-TCR complex (composed of pre-TCR alpha, TCR beta and CD3) and/or its combination with unknown ligand provide signals for further progression beyond the CD44-CD25+ stage. The deficiency of any component in pre-TCR complex would lead to the blockage of T cell development at early stages.