Fig. 4. Effects of IFN- on IL-2-mediated up-regulation and phosphorylation of the pocket proteins. Immunoblot analysis of pRb, p130, and p107 expression in quiescent (Day 0), PHA-treated (Day 3), IL-2-treated (Days 46), and IL-2/IFN--treated (Days 46) cells. Tubulin served as control for equal loading in each lane. The monoclonal p130 antibody used also detected an nonspecific band (*); this band has been described previously (27) .