Immunoprecipitation/Western Blot analysis: Rat Nb2-Sp T lymphoma cell lysates were prepared from cells that were treated without (lane 1) or with (lane 2) prolactin for 15 minutes. STAT5A was immunoprecipitated with 4ul of S7972-10. The immunoprecipitate was resolved by electrophoresis, transferred to nitrocellulose and probed with S7972-12 (1:1000). Proteins were visualized using a IgG (HRP) Pab GtxRb secondary antibody and a chemiluminescence detection system. Arrow indicates phosphorylated STAT5A (~95kD).