Modulation of CD6 function through interaction with Galectin‐1 and ‐3.

CD6 is a lymphocyte glycoprotein receptor that physically associates with the antigen‐specific receptor complex at the center of the immunological synapse, where it interacts with its ligand CD166/ALCAM. The present work reports the carbohydrate‐dependent interaction of CD6 and CD166/ALCAM with Galectin‐1 and ‐3, two well‐known soluble mammalian lectins. Both galectins interfered with superantigen‐induced T cell proliferation and cell adhesion phenomena mediated by the CD6‐CD166/ALCAM pair, while CD6 expression protected cells from galectin‐induced apoptosis. The results suggest that interaction of Galectin‐1 and ‐3 with CD6 and CD166/ALCAM might modulate some relevant aspects of T cell physiology.Galectin‐1 and ‐3 are two new interacting proteins for CD6 and its ligand CD166/ALCAM. Galectin‐1 and ‐3 modulate T cell proliferation and adhesion involving CD6‐CD166/ALCAM. The intracellular region of CD6 has protective effects against galectin‐induced T cell apoptosis. The interaction of Galectin‐1 and ‐3 with CD6 has a modulatory effect on T cell physiology. [ABSTRACT FROM AUTHOR]