Non-immunological recognition and killing of xenogeneic cells by macrophages. I. Repertoire of recognition

Non-immune non-activated mouse peritoneal macrophages efficiently kill in vitro xenogeneic fibroblasts from various avian species (xenolysis). The killing was less effective for rat and human fibroblasts. Macrophages of all inbred strains tested demonstrated xenolytic activity although they differed in destruction efficiency. Recognition and killing of target fibroblasts were not dependent on the presence of Ca⁺⁺ and Mg⁺⁺. Lysis of SPEFAS chicken fibroblasts free of viral antigen expression (gs^-chf^-) suggests that foreign recognition by macrophages does not involve viruses. Administration of anti-H-2 antiserum and of rabbit anti-macrophage serum (AMS) as well as addition of various carbohydrates or their derivatives to macrophages interacted with fibroblasts, failed either to block or identify foreign recognition sites on macrophages. Morphological studies by scanning electron microscopy showed protrusions of macrophage filopodia unidirected to the target xenogeneic fibroblast.