IMPAIRED DEVELOPMENT OF V-GAMMA-3 DENDRITIC EPIDERMAL T-CELLS IN P56(LCK) PROTEIN-TYROSINE KINASE-DEFICIENT AND CD45 PROTEIN-TYROSINE PHOSPHATASE-DEFICIENT MICE

To determine whether p56(lck) protein tyrosine kinase and CD45 protein tyrosine phosphatase are involved in the signal transduction during i ntrathymic differentiation of gamma/delta T cells, we have examined th e development of T cells expressing V gamma 3 T cell receptor (TCR) in mice deficient for either protein. The skin from both mice contained significantly reduced numbers of dendritic epidermal T cells expressin g decreased levels of V gamma 3 TCR at the cell surface. Analysis of t he fetal thymus from these mice suggested that maturation of V gamma 3 thymocytes was blocked at the immature stage that was characterized b y the low level of V gamma 3 TCR and the high level of heat stable ant igen. These results imply that both p56(lck) and CD45 are involved in the signal transduction during maturation of V gamma 3 T cells in the fetal thymus.