SELECTIVE DISBALANCES OF PERIPHERAL-BLOOD T-LYMPHOCYTE SUBSETS IN HUMAN CD3-GAMMA DEFICIENCY

The selection of T lymphocytes in the thymus and their activation upon the encounter with foreign antigens in the periphery require the aggr egation and signals of the T cell receptor (TcR)/CD3 complex and sever al surface molecules termed coreceptors (notably CD4 or CD8 and CD45). The spatial arrangement and interactions of the different molecules i n the resulting multimolecular recognition structure are mostly unknow n. Here we report, from studies on a healthy human CD3gamma deficiency , that the lack of the CD3gamma component of the TcR/CD3 complex is as sociated with a long-term severe defect of peripheral blood CD4+CD45RA + and CD8+ lymphocytes, whereas CD4+CD45RO+, B and natural killer lymp hocytes are unaffected. These results suggest that the CD3gamma site o f the TcR/CD3 complex is required for the peripheral representation of certain T cell types.