@entity1293 -mediated signaling is involved in a variety of functions in @entity1 cells. To determine whether this is true for immunocompetent cells, we generated mutant (Lck- @entity24146 -) @entity19 in which the @entity24146 gene was deleted in a T cell-specific manner using the Cre/loxP system. These @entity19 showed @entity73 cell development. Thymi at most ages were small and their architecture was disorganized. This defect was not due to increased thymocyte apoptosis but to decreased cell proliferation. T cell development was found to be severely arrested at the @entity1961 /CD8 double-negative 3 stage and the thymus contained very few double-positive or single-positive (SP) mature thymocytes. The mutant thymocytes showed impaired proliferative responses to anti- @entity5168 monoclonal antibody (mAb) stimulation or to the cytokines @entity2047 , @entity5003 or @entity2874 . In the spleen, the numbers of mature SP T cells were decreased and their proliferative responses to anti- @entity5168 plus @entity2047 or to anti- @entity10867 mAb were impaired. A severe impairment of @entity5168 -induced expression of @entity3783 was also observed. These data suggest that @entity24146 plays a critical role in the proliferation of thymocytes, which is necessary for early T cell development.

T cell-specific gene targeting reveals that XXXX is required for early T cell development.

@entity1 :: ('9606', 'Species') :: ['mammalian'] @entity2047 :: ('16183(Tax:10090)', 'Gene') :: ['IL-2'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity73 :: ('MESH:D003072', 'Disease') :: ['impaired early T'] @entity5168 :: ('12501(Tax:10090)', 'Gene') :: ['CD3'] @entity5003 :: ('111343(Tax:10090)', 'Gene') :: ['IL-1'] @entity3783 :: ('16184(Tax:10090)', 'Gene') :: ['CD25'] @entity2874 :: ('MESH:C536657', 'Disease') :: ['TNF'] @entity10867 :: ('12487(Tax:10090)', 'Gene') :: ['CD28'] @entity1961 :: ('12504(Tax:10090)', 'Gene') :: ['CD4'] @entity1293 :: ('3476', 'Gene') :: ['Alpha4'] @entity24146 :: ('18518(Tax:10090)', 'Gene') :: ['alpha4']
@entity24146 :: (18518(Tax:10090),Gene) :: ['alpha4']
