ROLE OF THE CYTOSKELETON IN CELL-TO-CELL TRANSMISSION OF HUMAN-IMMUNODEFICIENCY-VIRUS

We previously observed that when human immunodeficiency virus (HIV)-in fected T lymphocytes are added to epithelial cells, they adhere, polar ize, and secrete virions unidirectionally onto the epithelium. Epithel ial cells subsequently take up virus and become productively infected. We report here that colchicine treatment of T-lymphocyte suspensions induced lymphocyte polarization, redistribution of F-actin into a pseu dopod, and secretion of HIV from the pseudopod. Immobilization of T ly mphocytes on negatively charged plastic also caused redistribution of F-actin and unidirectional secretion of HIV onto the plastic. As neith er colchicine nor adhesion caused an increase in HIV secretion, they a pparently act by focusing secretion to the tip of the pseudopod. We sp eculate that adhesion-induced polar secretion of HIV, from activated m ononuclear cells onto epithelia, is a cytoskeleton-mediated process wh ich may be involved in HIV transmission in vivo.