Fig. 4.

Tyr-phosphorylation of STAT5b but not its SDS-PAGE electrophoretic mobility shift in response to IL-2 is inhibited by anti-CD4 MoAb and HIV env glycoproteins. Purified CD4 T cells were treated as described in Fig. 1. STAT5b Tyr-phosphorylation status was evaluated by immunoprecipitation (IP) with anti-STAT5b antibody followed by Western blotting (WB) using anti-P-Tyr MoAb (4G10) and anti-STAT5b antibody, as described in Materials and methods. Densitometric analysis of STAT5b phosphorylation is presented as in Fig. 1.