EXTRATHYMIC INTESTINAL T-CELL DEVELOPMENT - VIRTUAL-REALITY

Extrathymic T-cell development is a topic of considerable interest and debate, with important implications for the mechanisms of T-cell matu ration and repertoire selection. Recent evidence has suggested that in traepithelial T lymphocytes (IELs) of the small intestine can mature a nd undergo selection in the absence of a thymus. However, IEL precurso rs are present in the thymus and IEL development is know to be influen ced by the thymus. Here, Leo Lefrancois and Lynn Puddington discuss th ese data and suggest that the differentiation pathway of IEL precursor s is dependent on whether or not a thymus is present.