特異性：CD4/L3T4a, Mr 52 kDa CD4/L3T4 is a type I transmembrane glycoprotein expressed on most thymocytes and the helper/inducer subpopulation of mature T lymphocytes of all mouse strains tested.^1,2 CD4 has also been detected at low density on pluripotent hematopoietic stem cells, bone marrow myeloid precursors, and intrathymic lymphoid precursors. ^3-6 The CD4 antigen functions as a co-receptor, interacting with class II major histocompatability complex (MHC) molecules in the recognition of foreign antigens by T cells. ^1,2 In vivo and in vitro treatment with the GK1.5 mAb effectively depletes CD4^+ cells.^7,8 The mAb also blocks helper T cell responses to MHC class II antigens, including cytolysis, proliferation, allogeneic B cell help, and release of lymphokines.^1,8-13
