Figure 3.

T cells from FcRγ ζKO mice are functional. (a) CD4⁺ T cells from FcRγ ζKO mice respond to anti-TCR antibody. Purified CD4⁺ T cells from FcRγ ζKO, ζKO, and ζ⁺ mice were titrated for response to anti-TCR C_β antibody bound to plastic as described. In addition, T cells from FcRγ ζKO and ζ⁺ mice showed similar proliferative responses to various amounts of anti-TCR antibody after antibody titration whereas T cells from ζKO did not respond well to the antibody at the tested concentrations (data not shown). (b) T cells from FcRγ ζKO mice respond well to an antigenic peptide. Mice were primed with the mouse Eα peptide 52-68, and T cells from these animals were titrated for their activity to respond to in vitro challenge with Eα 52-68 as described. (c) CD8⁺ but not CD4⁺ T cells from FcRγ ζKO mice respond in primary mixed lymphocyte reactions. Spleen and lymph node cells from FcRγ ζKO, ζKO, and ζ⁺ mice were titrated for their ability to respond to stimulator cells bearing the allogeneic class I and class II proteins of H-2^k (Left), allogeneic class II of H-2^k without class I (Center), and syngeneic class I and class II of H-2^b (Right). Cultures were set up as described. The target and responding cells in the various reactions are indicated. (d) CD8⁺ T cells from FcRγ ζKO mice can become cytotoxic effector cells. H-2^d-specific cytotoxic T cells were generated from FcRγ ζKO, ζKO, or ζ⁺ mice by culture with spleen cells from H-2^d mice as described. Cytotoxic T cells generated in these cultures were assayed by killing H-2^d-bearing M12.C3 and P815 target cells. Stimulators and responding cells are indicated.