IMMUNOHISTOCHEMICAL DETECTION OF CANINE LEUKOCYTE ANTIGENS BY SPECIFIC MONOCLONAL-ANTIBODIES IN CANINE NORMAL-TISSUES

This report describes the immunocytochemical detection and distributio n of different canine leucocytes antigens (Thy-1, CD5, CD4, CD8, MHC-I I and B-cell antigen) by means of monoclonal antibodies (mAbs) in froz en tissue sections of lymphoid organs of the dog. CD5 is expressed exc lusively by T lymphocytes, Thy-1 is expressed by T-lymphocytes and in a variety of non-lymphoid tissues. The mAb against canine MHC-II could detect B and T lymphocytes, macrophages, fibroblasts and antigen pres enting cells. The CD4 antigen is expressed on many lymphocytes of the T-dependent areas of lymph organs and is also expressed by certain ant igen presenting cells. CD8 is expressed in a minor proportion of T cel ls. The mAb against B cells detected lymphocytes in lymphoid follicles and epithelial cells of the thymic medulla.