A monoclonal antibody (DT-2) recognizing canine T lymphocytes

A murine monoclonal antibody (DT-2) is described which has been raised against canine thymocytes. DT-2 activates complement and is reactive with most canine thymocytes, peripheral blood T cells, thoracic duct lymphocytes, bronchoalveolar lymphocytes, and T chronic lymphatic leukemia cells. The antibody is nonreactive with surface immunoglobulin-positive blood lymphocytes, monocytes, bronchoalveolar macrophages, null acute lymphatic leukemia cells, granulocytes, erythrocytes, and platelets. In mixed lymphocyte cultures DT-2 and complement eliminate the responding but not the stimulating cell population. Mitogen stimulation (phytohemagglutinin, concanavalin A) experiments revealed that the responding cell affected by DT-2 is of lymphoid and not of monocyte/macrophage origin. All our data suggest that DT-2 is an antibody reacting specifically with canine T cells.