FIG. 5.

SLAP-2 associates in vivo with tyrosine-phosphorylated proteins following TCR cross-linking. Thymocytes were isolated from 6-week-old mice and stimulated with either anti-CD3 alone or anti-CD28 alone or costimulated with anti-CD3 and anti-CD28 antibodies for the indicated periods of time. Lysates from stimulated thymocytes (5 × 10⁷) were immunoprecipitated with affinity-purified anti-SLAP-2-C antibody and immunoblotted. (Top panel) Antiphosphotyrosine immunoblot. (Middle panel) Anti-cCbl immunoblot. (Bottom panel) Results obtained after the blot was stripped and reprobed with affinity-purified anti-SLAP-2-C antibody. IP, immunoprecipitation; PI, preimmune sera.