RETRIEVAL OF LEUKOCYTE ANTIGENS IN PARAFFIN-EMBEDDED RAT-TISSUES

We compared the immunohistochemical reactivity of various rat leukocyt e antigens in frozen and paraffin-embedded thymus, spleen, abdominal l ymph node, liver, and brain tissues of healthy Sprague-Dawley rats, fi xed in various fixatives. Immune reactivity after fixation in Methacar n was superior to that of 4% neutral buffered formalin, a mercury-base d fixative (B-5), or Carnoy, Microwave (MW) antigen retrieval (AR) enh anced antigen reactivity. Ten of the 11 leukocyte antigens studied cou ld be retrieved in Methacarn-fixed, paraffin-embedded sections with a reactivity comparable to that obtained on frozen sections.