Relationships between the anti-HIV V-3-derived peptide SPC3 and lymphocytemembrane properties involved in virus entry: SPC3 interferes with CXCR4

SPC3 is a multiple antigen peptide derived from the V-3 loop of human immun odeficiency virus (HIV) envelope (Env). II exerts a potent anti-HIV activit y whereas it alters neither Env expression nor binding to CD4. Here, SPC3 b inding characteristics, its subsequent intracellular fate and the fact that it inhibited SDF(1)alpha binding to the lymphocyte surface provided strong arguments to conclude that it exerts its anti-HIV activity through interfe rence with the CXCR4 coreceptor. In contrast, it interferes with none of th e other major surface proteins and mechanisms involving V-3 and implicated in infection, as shown here. This work identifies the target mechanism of S PC3. (C) 2000 Federation of European Microbiological Societies. Published b y Elsevier Science B.V. All rights reserved.