Mouse T-lymphocyte subpopulations: relationships between function and Lyt antigen phenotype.

The study of cell-surface markers has permitted the dissection of lymphocyte populations into subsets and made possible many of the current ideas about how cells interact to produce an immune response. In particular, the Lyt molecules of the mouse, originally described by Boyse and his colleagues, have been of great importance in defining functionally distinct subsets of T cells and examining the interactions among them (reviewed in Ref. 2). A major question raised by these studies concerns the nature of the relationship between Lyt phenotype and the function of the T-cell subset so defined. Are such associations fortuitous, are they indirect manifestations of some other factor(s), or do they indicate that the molecules themselves have a functional role? In this article, Susan Swain and Richard Dutton discuss what is known about Lyt antigens, how their expression correlates with function of T cells and with the recognition of major histocompatibility complex (MHC) subregion antigens by T cells, and what role(s) such molecules may have in T-cell activities.