Enhancement of the HIV-1 inhibitory activity of RANTES by modification of the N-terminal region: dissociation from CCR5 activation

Although selected chemokines act as natural inhibitors of human immunodefic iency virus (HIV) infection, their inherent proinflammatory activity may li mit a therapeutic use. To elucidate whether the antiviral and signaling fun ctions of RANTES can be dissociated, several recombinant analogues mutated at the N terminus were generated and functionally compared with the wild-ty pe (WT) molecule, as well as with three previously described mutants. Subst itution of selected residues within the N-terminal region caused a marked l oss of antiviral potency. By contrast, two unique analogues (C1.C5-RANTES a nd L-RANTES) exhibited an increased antiviral activity against different CX CR4-negative HIV-1 isolates grown in primary mononuclear cells or in macrop hages. This enhanced HIV-biocking activity was associated with an increased binding affinity for CCR5. Both C1.C5-RANTES and L-RANTES showed a dramati cally reduced ability to trigger intracellular calcium mobilization via CCR 3 or CCR5, while potently antagonizing the action of the WT chemokine. By c ontrast, two previously described analogues (RANTES(3-68) and AOP-RANTES) m aintained a WT ability to trigger CCR5-mediated signaling, while a third on e (RANTES(9-68)) showed a dramatic loss of antiviral activity. These data d emonstrate that the antiviral and signaling functions of RANTES can be unco upled, opening new perspectives for the development of chemokine-based ther apeutic approaches for HIV infection.