Gut-associated lymphoid tissues are responsible for the generation of IgA-secreting cells. However, the function of the caecal patch, a lymphoid tissue in the appendix, remains unknown.

The authors analyse the role of the caecal patch using germ-free mice colonized with intestinal bacteria after appendectomy. Appendectomized mice show delayed accumulation of IgAt cells in the large intestine, but not the small intestine, after colonization. Decreased colonic IgAt cells correlate with altered faecal microbiota composition. Experiments using photoconvertible Kaede-expressing mice or adoptive transfer show that the caecal patch IgAt cells migrate to the large and small intestines, whereas Peyer's patch cells are preferentially recruited to the small intestine. IgAt cells in the caecal patch express higher levels of CCR10. Dendritic cells in the caecal patch, but not Peyer's patches, induce CCR10 on cocultured B cells. Thus, the caecal patch is a major site for generation of IgA-secreting cells that migrate to the large intestine.

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Contact:

Kiyoshi TAKEDA
Mucosal Immunology
Immunology Frontier Research Center (WPI-IFReC), Osaka University