DESCRIPTION: (Applicant's Abstract) The intact blood-brain barrier (BBB) protects brain cells from many virus infections possibly including HIV-1. Hypothesis: Cocaine may increase penetration of HIV-1 into the central nervous system (CNS), possibly by a tumor necrosis factor-alpha (TNF-alpha)-responsive mechanism, and alter preferential migration of T cell subsets across the BBB and perturb cell-mediated immunity in CNS. Preliminary work: TNF-alpha and cocaine increased penetration of cell-free HIV-1 across a BBB model constructed with human brain microvascular endothelial cells (BMVEC). Cocaine inhibited transmigration of CD4+CD45RA (memory) subset in vitro and increased WBC and lymphocyte counts in vivo. Methods: HIV-1 penetration into the lower chamber of the BBB model (constructed with BMVEC and fetal astrocytes on a porous membrane coated with fibronectin) measured by p24 antigen assay of infectious virus; FACScan analysis of T cell subsets; Elisa assay of cytokines. Specific Aims: #1 penetration of HIV-1 in BBB models treated with TNF-alpha or cocaine, and the mechanism of HIV-1 penetration, such as transcytosis; #2 immune status (cell counts and cytokine production) and migratory properties of mononuclear cells before and after experimental intravenous cocaine administration in cocaine-addicted individuals; #3 TNF-alpha, interferon-gamma, interleukin (IL)-1, IL-4, IL-6, IL-10, IL-12 production and migratory properties of mononuclear cells from normal donors stimulated by cocaine in vitro. Projected accomplishments; We will determine (a) whether TNF-alpha and cocaine disrupt the BBB and increase HIV-1 penetration by transcytosis, (b) whether alterations of cell-mediated immunity are induced by cocaine in vivo and in vitro, (c) which cell types secrete cytokines in response to cocaine stimulation, and (d) whether TNF-alpha concentrations in the plasma of cocaine-addicted subjects may have adverse effects on the BBB.