Heterogeneity of IL-22-producing Lymphoid Tissue Inducer-like Cells in Human and Mouse

Lymphoid tissue inducer (LTi) cells have been characterized in mouse as a key cell when secondary lymphoid tissues are organized during development and memory T cells are formed after birth. In addition to their involvement in adaptive immune responses, recent studies show that they contribute to innate immune responses by producing large amount of interleukin (IL)-22 against microbial attack. Here, we compare IL-22-producing LTi and LTi-like cells in human and mouse and discuss their heterogeneity in different tissues.

A new NK-like cell subset of IL-22 producer:NK-22 cells / 中国免疫学杂志

The mucosal tissues form the interface between the outside world and the sterile environment of the body.Innate immunity plays a critical role in the maintenance of mucosal homeostasis.Recently,a new subset of innate immune cells named NK-22 has been discovered to reside at tonsil and intestine both in human and mice.NK-22 cells share features with both natural killer (NK) cells and lymphoid tissue-inducing (LTi) cells.NK-22 cells express a variety of NK cell receptors and phenotypically resemble that of immature NK cells (iNKs).However,they are quite different from NK cells in function and development.NK-22 cells lack conventional NK cell cytotoxic function and produce IL-22 instead of IFN-?.It is currently considered that NK-22 cells are not a subset of NK cells.They develop from LTi cells and the development process depends on ROR?t and commensal microflora.NK-22 cells are involved in immune protection against the pathogen Citrobacter rodentium.The IL-22 secreted by NK-22 cells contributes to epithelial cell resistance to injury and mucosal tissue repair after microbial infection.