Animals, Antigens, CD, Antigens, Differentiation, T-Lymphocyte, Blotting, Northern, CD8 Antigens, Cell Division, Cell Line, Clone Cells, Female, Flow Cytometry, Histocompatibility Antigens, Leukocyte Common Antigens, Lymphokines, Mice, Mice, Inbred CBA, Mice, Inbred DBA, Phosphoprotein Phosphatases, Protein Tyrosine Phosphatases, Receptors, Antigen, T-Cell, Signal Transduction, T-Lymphocytes, Cytotoxic