PHYLOGENY OF LYMPHOCYTE HETEROGENEITY - CYTOTOXIC ACTIVITY OF CHANNELCATFISH PERIPHERAL-BLOOD LEUKOCYTES DIRECTED AGAINST ALLOGENEIC TARGETS

Channel catfish peripheral blood contains leukocytes that function as cytotoxic effecters directed against a variety of long-term cultured a llogeneic, but not xenogeneic, targets. These effector cells are proba bly distinct from macrophages, B cells, and nonspecific cytotoxic cell s. The cytotoxic activity of these effector cells was inhibited with m onoclonal antibody 1H5. Although this reagent appears to react with a catfish cell surface molecule akin to the integrin LFA-1 present on th e surface of nearly all leukocytes, it does not clarify the question a s to whether or not these effecters are related to T cells.