NEW ANTISERUM AGAINST KI-67 ANTIGEN SUITABLE FOR DOUBLE IMMUNOSTAINING OF PARAFFIN WAX SECTIONS

Aims-To prepare a rabbit antiserum equivalent to MIB 1 to permit the simultaneous assessment of cell proliferation and other markers of interest using double labelling studies. Methods-Rabbits were immunised with a synthetic peptide deduced from the cDNA sequence coding for the Ki-67 antigen. Serum samples were tested for immunoreactivity using different immunobiochemical methods. Results-A polyclonal antiserum was derived which detects the native as well as recombinant parts of the Ki-67 antigen in different test systems. Furthermore, the antiserum stains the Ki-67 antigen in routinely processed, paraffin wax embedded material. Conclusions-After antigen unmasking by microwave treatment the antiserum described here represents a powerful tool for the determination of growth fractions even in archival material. It is especially suitable for double staining experiments in combination with monoclonal antibodies.