CD4+8- or CD4-8+thymocytes have been regarded as direct progenitors of peripheral T cells. However, recently, we have found a novel NK1.1+ subpopulation with tilted T cell antigen receptor (TcR) Vp family among heat-stable antigen negative (HSA-) CD4+8-thymocytes. In the current study, we show that these NK1.1+ CD4+8-thymocytes, which represent a different lineage from the major NK1.1- CD4+8-thymocytes or CD4+ lymph node T cells, vigorously secrete interleukin (IL)-4 and interferon (IFN)-y upon stimulation with immobilized anti-TcR-aP antibody. Found the major immature thymocyte subpopulation can be readily separated from the immunocompetent minor subpopulation by agglutination with peanut agglutinin (PNA) and can be recovered as viable single cells by dissociation of the agglutinated cells with “D-galactose.

The drug cyclosporine A (CsA) has been shown to interfere the autoimmune process, allowing the escape of normally ‘forbidden’ T-cell clones and the appearance of autoimmune disease. The majority of thymus cells are at a nonproliferating end stage, during which three percent of all CD4+CD8+ cortical thymocytes are chosen on the basis of appropriate T-cell antigen-receptor (TcR) specificity to become CD4-CD8+ or CD4+CD8- mature thymocytes.