ANALYSIS OF ALLOREACTIVE AND CYTOTOXIC CANINE LYMPHOCYTES AND THEIR PRECURSORS WITH MURINE MONOCLONAL ANTIBODIES

Abstract

Four murine monoclonal antibodies were used in cytolytic assays to identify cell populations involved in canine T cell effector functions. Antibody DT-2, directed at T cells, and antibody DLy-6, a panlymphocyte antibody, inhibited mixed lymphocyte culture (MLC) responses and cytotoxic lymphocyte (CTL) activity only when lymphocytes were treated before culture (day 0), but they had no significant effect on these functions when cells were treated after 6 days in culture. Antibody DLy-1, reacting with canine lymphocytes and monocytes, abrogated MLC responses and CTL activity when responder cells were treated on day 0. When cells were treated after 6 days in culture, MLC responses were reduced to 47% of control, whereas CTL activity increased slightly. In contrast, the anti-Ia antibody 7.2 significantly reduced MLC responses and CTL activity of cells treated on either day 0 or day 6 of culture, suggesting that canine CTL express Ia antigens.