The CD2-LFA-3 and LFA-1-ICAM pathways: relevance to T-cell recognition.

No process is more central to T-lymphocyte function than cell-cell adhesion, yet it is only recently that interest in lymphocyte adhesion has burgeoned. Neglect of adhesion is particularly surprising since immunologists are surrounded by a veritable sea of adhesive interactions of lymphocytic cells: transformed lymphocytes grow in aggregates, stimulated lymphocytes aggregate and T cells conjugate with their targets. In retrospect, it is obvious that all lymphocyte adhesion (both antigen-specific and seemingly non-specific adhesive interactions) has to be based on specific receptor-ligand interactions. In this review Malegapuru Makgoba, Martin Sanders and Stephen Shaw focus primarily on the two molecular pathways of lymphocyte adhesion that have been shown to play a critical role in facilitation of antigen-specific recognition, namely CD2 and its ligand, lymphocyte function associated antigen-3 (LFA-3), and LFA-1 and its ligand, intercellular adhesion molecule-1 (ICAM-1). A variety of excellent recent reviews have dealt with this and related aspects of T-cell adhesion. Of particular interest is the review that follows in this issue: it deals with the CD44 molecule which has also been implicated in both adhesion and activation of T cells.