Cytochemical analysis of alkaline phosphatase and esterase activities and of lectin‐binding and anionic sites in rat and mouse Peyer's patch M cells

Abstract

M cells in Peyer's patch follicle epithelium endocytose and transport luminal materials to intraepithelial lymphocytes. We examined (1) enzymatic characteristics of the epithelium covering mouse and rat Peyer's patches by using cytochemical techniques, (2) distribution of lectin-binding sites by peroxidase-labeled lectins, and (3) anionic site distribution by using cationized ferritin to develop a profile of M cell surface properties. Alkaline phosphatase activity resulted in deposits of dense reaction product over follicle surfaces but was markedly reduced over M cells, unlike esterase which formed equivalent or greater product over M cells. Concanavalin A, ricinus communis agglutinin, wheat germ agglutinin and peanut agglutinin reacted equally with M cells and with surrounding enterocytes over follicle surfaces. Cationized ferritin distributed in a random fashion along microvillus membranes of both M cells and enterocytes, indicating equivalent anionic site distribution. Staining for alkaline phosphatase activity provides a new approach for distinguishing M cells from enterocytes at the light microscopic level. Identical binding of lectins indicates that M cells and enterocytes share common glycoconjugates even though molecular groupings may differ. Lectin binding and anionic charge similarities of M cells and enterocytes may facilitate antigen sampling by M cells of particles and compounds that adhere to intestinal surfaces in non-Peyer's patch areas.

M-cells in the rabbit tonsil exhibit distinctive glycoconjugates in their apical membranes.

“…Because both oropharynx and cecum are heavily populated by bacteria (Miller, 1990;Hill and Drasar, 1975), the M-cell-specific glycoconjugates might represent adaptations to the local microbial flora that allow the selective uptake of microbial antigens for the initiation of immunological tolerance against these bacteria. This view is supported by the absence of M-cell-specific glycoconjugates in the small intestine of rabbits and rats (Jepson et al, 1995;Gebert and Hach, 1993;Owen and Bhalla, 1983) -a habitat in which the indigenous microbial flora probably plays a minor role (Savage, 1977). In addition, the cecum of mice, which normally contains large numbers of indigenous bacteria (Koopman et al,l983), bears M-cells that considerably differ in their lectin binding pattern from those in the small intestinal Peyer's patches (Clark et al, 1994(Clark et al, ,1995Giannasca et al, 1994).…”

Comparative Analysis of EspF Variants in Inhibition of Escherichia coli Phagocytosis by Macrophages and Inhibition of E. coli Translocation through Human- and Bovine-Derived M Cells

“…This is referred to as follicle-associated epithelium (FAE) and is a site of active immunological function. In contrast to villous epithelium, FAE contains no or fewer goblet cells (67), defensin-and lysozyme-producing Paneth cells (26,27) and expresses low amounts of membrane-associated hydrolases (68). The M cells generally lack the distinct microvilli and thick filamentous brush border glycocalyx (24) and instead have variable microfolds.…”

Ultrastructural Study on the Epithelial Responses against Attachment of Indigenous Bacteria to Epithelial Membranes in Peyer's Pathes of Rat Small Intestine

“…Antigenic substances such as pathogenic microorganisms are eliminated by nonspecific and specific defense mechanisms mediated by gutassociated lymphatic tissue (GALT) [11,34]. The follicleassociated epithelium (FAE) of Peyer's patches contains M cells which play special functions that transcytose various antigens and microorganisms from the intestinal lumen to the dome area [23,27]. Some antigens are further delivered to the antigen-presenting cells to induce the mucosal immune responses [14,25].…”