Persorption Mechanisms of Luminal Antigenic Particulates via Apoptotic Epithelial Cells of Intestinal Villi into Systemic Blood Circulation in Orally Immunized Rats

Abstract

ABSTRACT. The possibility of persorption of prefixed bovine serum albumin-coated sheep erythrocytes (BSA-SEs) from mucous epithelial cells and its mechanisms were investigated in rats orally immunized by BSA for 14 consecutive days. On the day after the final oral immunization, the rats were duodenally perfused by BSA-SEs or non-coated SEs. BSA-SEs were also duodenally perfused in nonimmunized rats. Thirty min after perfusion, BSA-SEs were significantly more engulfed by late-apoptotic-stage villous columnar epithelial cells in the orally immunized rats than those in other experiments. The specific antibody (SpAb) was detected on the surfaces of BSA-SEs in rats with oral immunization. In Peyer's patches of all animals, no SEs reached the follicle-associated epithelium, because of the close attachment of follicle-associated intestinal villi and the thick mucous layer. BSA-SEs were more frequently persorbed into portal blood in the orally immunized rats than in other rats. Small numbers of BSA-SEs or SEs were detected in the systemic blood of all animals. BSA-SEs were also histologically found in the blood vessels of the liver, but not in mesenteric lymph nodes. These findings suggest that sensitized antigenic particulates are taken up by late-apoptotic-stage villous columnar epithelial cells in the small intestine and are finally persorbed into the systemic blood circulation. The uptake of antigenic particulates might be mediated by its luminal SpAb.

Persorption of IgG-Fc-Coated Particulates from Intestinal Lumen into Portal Blood via Villous Columnar Epithelial Cells in Rat Small Intestine

“…Antigenic macromolecules and particulates and their specific antibodies are also absorbed by epithelial cells at the late stage of apoptosis in orally pre-immunized rats [28,29]. In the present study, the absorption of Fc-SEs was exclusively found in epithelial cells with morphological signs of apoptosis.…”

“…On the other hand, duodenally administered BSA-SEs are histologically found in the blood vessels of the liver, but not in lymph vessels or mesenteric lymph nodes in orally pre-BSA-immunized rats. Therefore, the SEs taken up by epithelial cells are considered to be directly transported to the portal blood and finally reach the systemic blood circulation [28]. In the present findings, Fc-SEs passed through the endothelium of the subepithelial blood capillaries and were present in the capillary lumen, but not in the lymph vessels.…”

“…Intestinally administered HRP-containing endosomes are more evident in the epithelial cells of rats pre-immunized by HRP than in those of non-immunized rats [27]. In our previous study, the absorption of antigenic macromolecules and particulates by epithelial cells is mediated by their specific antibodies in orally pre-immunized rats [28,29]. Thus, lumen-specific antibodies are deeply committed to absorption of luminal antigens in the rat small intestine.…”

“…In adult rats, luminal IgG is absorbed from intestinal epithelial cells [28]. The IgG is engulfed and transported by endocytosis mediated by receptors on the intestinal epithelial cells in young rats [19].…”

Lectin Histochemical Detection of Special Sugars on the Mucosal Surfaces of the Rat Alimentary Tract

“…These portions are also epithelial cell-shedding sites and accumulation sites of epithelial cells in the late-apoptotic stage in rats [30,33,34]. These accumulation sites of epithelial cells in the lateapoptotic stage also absorb the luminal food-derived antigens and their antibody complexes in the rat small intestine [43,44]. On late-apoptotic-stage epithelial cells in the rat jejunoileum, we detected (GlcNAc) [2][3][4] and -DGal(1-3)D-GalNAc exclusively [9].…”