AbstractThe effects of different fixatives on the immunohistochemical staining of lymphoid surface antigens in paraffin embedded sections were studied using avidin-biotin-peroxidase complex (ABC) technique. We found that the best results were achieved in B-5 fixed tissues. The demonstration of T and B cell antigens in formalin fixed tissues gave satisfactory results and did not require trypsinization, with the exception of leucocyte common antigen and MTl. Fixatives such as Bouin's fluid and acid formalin showed good preservation of the antigenicity of only B cells, and the use of trypsin digestion did not improve the results; on the contrary, it abolished the immunostaining. (The J of Histotechnol12:15, 1989)