THE ACCESSORY CELL-ACTIVITY OF PORCINE INTESTINAL MACROPHAGES IN THE INDUCTION OF T-CELL RESPONSES

Although intestinal macrophages stimulated significant T cell response s to MHC class II antigens and polyclonalmitogens, they were weak stim ulators of ovalbumin-driven responses. These cells showed numerous and large endocytic vacuoles, lysosomes and phagolysosomes which may be i ndicative of active phagocytosis during the isolation process. The poo r antigen presenting activity of the cells in protein antigen-elicited may be an in vitro artifact attributed to acquired inefficiency in an tigen uptake and/or processing.