特異性：alpha chain of the murine CD8 heterodimer, Mr 32-34 kDa In the mouse, CD8 exists in two forms: (i) a CD8 heterodimer composed of an alpha chain (CD8 alpha /Lyt-2) and a beta chain (CD8 beta /Lyt-3); and (ii) a homodimer of two alpha chains. The heterodimer is found on the surface of essentially all thymocytes and the "suppressor/cytotoxic" subpopulation of mature T lymphocytes. Subsets of intestinal intraepithelial lymphocytes express CD8 alpha without CD8 beta. It has been suggested that CD8^+ beta ^- T cells mature extrathymically, while development of the CD8 alpha ^+ beta ^+ population of T cells is thymus-dependent. CD8 acts as a coreceptor with MHC Class I-restricted T cell receptors in antigen recognition and positive selection of MHC class I-restricted CD8^+ T cells. In vivo and in vitro treatment with the 53-6.7 monoclonal antibody effectively depletes CD8 alpha ^+ cells. The 53-6.7 monoclonal antibody also blocks allogeneic help specific for class I MHC antigens and T cell responses to IL-2. 1-8
