B-LYMPHOCYTE AND T-LYMPHOCYTE ARE ENHANCED IN THE GUT OF PIGLETS FED HEAT-TREATED SOYBEAN PROTEINS

Gut immune responses have been suspected in food hypersensitivity reac tions such as those to soyabean proteins in early-weaned piglets. The present study examines the lymphoid cell subset distribution in piglet s fed heat-treated (HTSP) or ethanol-treated soyabean proteins (ETSP). Duodenal cryosections of 4-week-old HTSP piglets (n = 10) and ETSP pi glets (n = 8) were analysed for IgA, IgM, IgG1 and IgG2 positive cells , CD2, CD4, CD8, WC1 T cell positive antigens using immunohistochemica l peroxidase reactions. Densities of IgM+ and IgA+ cells were three ti mes and, IgG1+ and IgG2+ six times higher in the lamina propria of HTS P piglets compared with ETSP (P < 0.05). Increased CD2+ T cells were a ccounted for by a rise in both CD4+ and CD8+ T cell subsets in the lam ina propria (P < 0.01) as well as in the epithelium of the duodenal mu cosa of piglets fed HTSP. The density of the WC1+ T cell subset in the epithelium was significantly higher in HTSP than in ETSP piglets (P < 0.01). Immune reactions in the duodenal mucosa, involving both B and T lymphocytes may be related to atrophy of the duodenal villi in HTSP piglets.