Effective removal of CD45 from microsomal fractions by anti-CD45 immunoprecipitation. Microsomal fractions of thymocytes from wild-type or CD45-AP-null mice and of ALST-1 cells transfected with either CD45-AP or empty vector were immunoprecipitated with anti-CD45 antibody-conjugated beads. Fractions before and after immunoprecipitation were analyzed by immunoblotting with anti-CD45 antibody.