Immunohistological detection of human cytotoxic/suppressor T cells using antibodies to a CD8 peptide sequence.

To evaluate whether cytotoxic/suppressor T cells can be detected in paraffin wax embedded human tissue samples using antibodies to a synthetic CD8 peptide sequence. Polyclonal and monoclonal antibodies were raised against a 13 amino acid peptide sequence from the cytoplasmic portion of the alpha chain of the human CD8 molecule. These antibodies specifically detected the native form of the CD8 polypeptide when tested by immunoprecipitation with radiolabelled T cells, and gave the expected staining pattern for cytotoxic/suppressor T cells in cryostat sections. Being raised in rabbits, the polyclonal antibodies were also useful for double labelling for CD8 in conjunction with monoclonal antibodies. CD8 positive cells could also be detected in paraffin wax embedded tissues. This was achieved without prior treatment of the sections if the tissue had been fixed in Bouin's fixative. When tissues had been exposed to conventional formalin fixation, preliminary microwave treatment was required. These findings provide further evidence that antibodies against leucocyte associated antigens, capable of reacting on paraffin wax embedded tissue, can be produced by immunisation with synthetic peptide sequences.