The Development of M Cells in Peyer's Patches Is Restricted to Specialized Dome-Associated Crypts

Abstract

It is controversial whether the membranous (M) cells of the Peyer's patches represent a separate cell line or develop from enterocytes under the influence of lymphocytes on the domes. To answer this question, the crypts that produce the dome epithelial cells were studied and the distribution of M cells over the domes was determined in mice. The Ulex europaeus agglutinin was used to detect M cells in mouse Peyer's patches. Confocal microscopy with lectin-gold labeling on ultrathin sections, scanning electron microscopy, and laminin immuno-histochemistry were combined to characterize the cellular composition and the structure of the dome-associated crypts and the dome epithelium. In addition, the sites of lymphocyte invasion into the dome epithelium were studied after removal of the epithelium using scanning electron microscopy. The domes of Peyer's patches were supplied with epithelial cells that derived from two types of crypt: specialized dome-associated crypts and ordinary crypts differing not only in shape, size, and cellular composition but also in the presence of M cell precursors. When epithelial cells derived from ordinary crypts entered the domes, they formed converging radial strips devoid of M cells. In contrast to the M cells, the sites where lymphocytes invaded the dome epithelium were not arranged in radial strips, but randomly distributed over the domes. M cell development is restricted to specialized dome-associated crypts. Only dome epithelial cells that derive from these specialized crypts differentiate into M cells. It is concluded that M cells represent a separate cell line that is induced in the dome-associated crypts by still unknown, probably diffusible lymphoid factors.

Intestinal villous M cells: An antigen entry site in the mucosal epithelium

“…A standard lectin staining procedure was used for the detection of murine M cells (23). Mucus-free small intestine of naive BALB͞c or C57BL͞6 mice, with or without PP, was fixed in 4% paraformaldehyde for 1 h, washed, and then blocked with 10% FBS in PBS containing 0.1% glycine.…”

“…1 a-i). UEA-1, which possesses specificity for carbohydrate structures containing ␣(1-2)-fucose, selectively binds to the entire plasma membrane of PP M cells but not to WGA ϩ columnar epithelial cells (23). To further confirm the specificity of UEA-1 staining, we have performed a blocking experiment using 50 mM soluble fucose.…”

Bacterial Translocation from Intestine: Microbiological, Immunological and Pathophysiological Aspects

“…Необходимо отметить общебиологическое значение БТ, которое не является простым пассивным процессом, а предусматри-вает активный микробный забор (Sampling) с участием фагоцитирующих клеток и опсонических гуморальных факторов (комплемент, антитела и др.). В механизмах мукозного иммунитета и взаимодействия с кишечными бактериями и лимфоидной тканью, ассоциированной со слизистой оболочкой кишечника, в частности с Пейеро-выми фолликулами, особую роль играют так называемые М клетки [27,28]. Их способность к эндоцитозу кишеч-ных бактерий повышается при участии гликопротеина 2, играющего определенную опсонизирующую роль и сти-мулирующего мукозный иммунный ответ [29,30].…”

Ankara tavşanı ileum epitelinde vimentin pozitif hücrelerin yapısal özellikleri

“…Sunulan çalışmada, lokalizasyonları ve morfolojileri farklı iki M hücresi belirlenmiştir. Bunlardan birisi, dom bölgelerinin üst kısımlarındaki FAE'lerde ince dar sitoplazmalı olan ve sitoplazmik invaginasyonla İEL'leri çevreleyen olgun M hücreleri, diğeri ise kriptlere komşu FAE'lerde prizmatik şekilli ve İEL içermeyen olgunlaş-mamış M hücreleri olarak tanımlanmıştır (5,6,13,16,25). M hücrelerinin komşu enterositlerden daha kısa ve düzensiz mikrovilluslara sahip olduğu ve apikal sitoplazmalarında çok sayıda mitokondriyon, vezikül ve vakuolün bulunduğu bildirilmiştir (3,22,23).…”