Reactivity of antibodies directed against human antigens with surface markers on canine leukocytes.

A panel of anti-human antibodies was used in order to investigate their cross-reactivity with canine leukocytes. The labeling was carried out at the microscopic level by immunocytochemical staining. Of 50 antibodies 22 cross-reacted with canine leukocytes from afferent lymph and peripheral blood. All leukocytes reacted with MHM23 (CD18). Two anti-HLA DR antibodies, DK22 and L243, reacted mostly with veiled cells and with PHA-stimulated lymphocytes, whereas TAL1B5 was cross-reactive with all canine lymphocytes. The activation markers CD25, Ki-67, PCNA were identified on PHA-stimulated lymphocytes with ACT1, Ki-67 and PC10 clone produced antibodies. Canine eosinophils reacted with MHM6 (CD23) antibody. A large number of antibodies reacted with canine lymph veiled cells. Canine granulocytes and a subset of lymphocytes were stained with the anti-CD15 antibody only after treatment of cytospins with neuraminidase.