CHARACTERIZATION OF ANTIGEN-PRESENTING ACTIVITY OF SMALL-INTESTINAL LAMINA PROPRIA MACROPHAGES ISOLATED FROM NORMAL SUCKLING PIGLETS

Susceptibility of neonatal animals to infection is due to immunologica l immaturity and this is partly due to lack of competence of macrophag es. This study was, therefore, intended to elucidate the antigen prese nting activity of non-lymphoid cells of the intestinal lamina propria of the newly born piglets. Intestinal macrophages (LPM) isolated from 7-14 days old piglets following enzymatic digestion of tissues induced significant but low T cell proliferation in response to phytohemagglu tinin (PHA). They also elicited low but significant oxidative mitogeni c and allogeneic mixed lymphocyte responses which were Major Histocomp atibility Complex (MHC) class II-dependent. The results indicate that intestinal lamina propria macrophages of neonate pigs show an apprecia ble but low degree of immunological competence.