Immunolocalization of the complement component C1q in the mucous membrane of the human duodenum (duodenitis II-III degree)

Abstract

In order to establish the supposed role of the complement system in the regulation of homeostasis and defense reactions in the intestinal epithelium, an immunofluorescent analysis was conducted of localizing the C1q complement component in the inflamed mucosa of the human duodenum (DM) (duodenitis II-III degree) using C1q-specific antibodies. The findings suggest a pronounced presence of the C1q complement component in various DM areas during inflammation, both in the epithelial layer and in the lamina propria, where C1q is localized in the region of the basolateral membrane of enterocytes and some free cells, presumably neutrophils, macrophages and mast cells. A C1q-specific reaction in the epithelial cells and secretory ducts of the duodenal glands indicates a possible secretion of C1q. Co-localization of C1q, cathepsin G and cell adhesion proteins in the DM epithelium implies their interaction in the regulation of tissue metabolism, modification and maintenance of the barrier properties of the intestinal epithelium in normal and with inflammation.