DETECTION OF EQUINE AND BOVINE T-LYMPHOCYTE AND B-LYMPHOCYTE IN FORMALIN-FIXED PARAFFIN-EMBEDDED TISSUES

Formalin-fixed paraffin-embedded sections of equine and bovine lymph n odes, spleen, thymus, and Peyer's patches were incubated with monoclon al antibodies to B-lymphocyte markers BLA.36, B29, and mb-1 and T-lymp hocyte markers CD3 and CD5. The monoclonal antibody BLA.36 reacted wit h 80-90% of lymphocytes in the germinal centers and mantle zones of fo llicles in lymph nodes, spleen, and Peyer's patches. In addition, 90% of lymphocytes in the marginal zone of the spleen, and variable number s of lymphocytes within lymph node medullary cords were immunopositive for BLA.36. Antibodies to B29 and mb-1 produced similar staining patt erns as BLA.36 with fewer positive cells in the germinal centers and m edullary cords. BLA.36, B29, and mb-1 reacted with 30-50% of lymphocyt es in the medulla of the thymus and with 5-10% of lymphocytes in the c ortex. CD3 and CD5 reacted with 90% of lymphocytes in the paracortex a nd parafollicular zones of lymph nodes, spleen, and Peyer's patches; 4 0-50% of lymphocytes in the medullary cords of lymph nodes, and scatte red positive cells within follicles. Anti-CD3 antibody reacted with 95 % of lymphocytes in the splenic red pulp, but antibodies directed agai nst CD5 reacted only faintly with approximately 5-10% of lymphocytes i n the red pulp. CD3 and CD5 reacted with 50-60% of cells in the medull a of the thymus and with 40-80% of lymphocytes in the thymic cortex. T he biochemical characterization of the antibodies by Western blotting against lysates of equine and bovine peripheral blood mononuclear cell s confirmed that antibodies to BLA.36, mb-1, B29, CD3, and CD5 detecte d molecules of the same approximate molecular mass as found on lymphoi d cells of human beings and rats. (C) 1997 Elsevier Science B.V.