Development of intestinal M cells

Abstract

Intestinal epithelium contains several specialized cell types including M cells, which can be found in the follicle-associated epithelium (FAE) or occasionally on the villi. M cells are critical for sampling of intestinal flora and for transferring pathogens across the epithelial barrier for recognition by the immune system. Development of M cells on the villi (M(v)) is independent of the presence of lymphocytes, while development of the FAE and M cells within the FAE (M(f)) is dependent on B lymphocytes. Here, the concept is discussed that B cells are not required for induction of M(f) differentiation but are required for transition to and maintenance of the mature M(f) phenotype. Signaling pathways possibly involved in the B-cell-independent stages of M-cell development are also discussed.

Morphological and Immunohistochemical Identification of Villous M Cells in the Small Intestine of Newborn Piglets

“…It is thought that the development of M cells is dependent on contact with lymphocytes in PP or exposure to exogenous antigen (Mach et al, 2005). However, in this study of newborn piglets which had limited contact with the environment and in the absence of intestinal lymphoid tissue still appear to have developed M cells and so challenges the accepted assumption.…”

CD137 Is Required for M Cell Functional Maturation but Not Lineage Commitment

“…Lymphocyte expression of CD137 is associated with T cell costimulation, 29,34,36 so it may be that the connection to M cells is through CD4 T cell interactions with B lymphocytes, which are known to be critical to M cell development. 20,21 Interestingly, however, CD137 expression was also required in the radioresistant stromal cells, as wild-type bone marrow failed to induce normal M cell function in the CD137-deficient recipients. This would be consistent with a second role for CD137 in the interactions between B cells and M cells.…”

“…Although lymphotoxin/TNF ligands are known to be important in the development of secondary and tertiary lymphoid tissues, these cytokines are apparently not by themselves sufficient to induce full maturation and function of M cells in vivo; the physical association with B cells (or subepithelial dendritic cells) may provide additional important signals. 20,21 Similarly, a recent report suggests that signaling through intestinal epithelium expression of the TNF receptor superfamily member RANK (TNFRSF11a) is also important in M cell differentiation, likely through interaction with the ligand RANKL (TNFSF11) on stromal cells. 47 Our results suggest that CD137/CD137L signaling between M cell progenitors and basolateral pocket B cells may provide at least one of these important signals that induce final functional maturation of developing M cells.…”

Development of adjuvant for effective oral vaccine application

“…이후 M cell이 점막의 여러 MALT에 서 발견되었으나 M cell을 규정하는 marker들이 명확하지 않아 주로 형태학적 특성에 따라 분류되었다. 그러나 in vivo M cell 혹은 in vitro M-like cell culture를 통한 연구가 진행됨에 따라 M cell의 apical에서 β1 integrin, ICAM-1, α-L-fucose, GM1 ganglioside, CCR5 receptor, IgA specific receptor 등의 발현이 알려지며, M cell의 기능에 대한 이 해가 점차 확대되기 시작하였다 (Brayden et al 2005;Jepson et al 2004;Kuolee and Chen 2008;Mach et al 2005 (Brandtzaeg et al 2008;Parrott 1976).…”