Injection of rats subcutaneously with Ha-MuSV transformed NRK cells and screening of sera of individual animals to identify those with the strongest immune response against p21. Spleens were removed from the immunised animals and cell fusion of immune lymphocytes with rat myeloma cell line 210RCY3 Ag 1.2.3 (Y3) was carried out. Supernatants were harvested and assayed for antibodies to p21 by GDP binding assay or immunofluorescence on Ha-SV-transformed MDCK cells, followed by testing for the ability of the antibodies to immunoprecipitate p21.
