12th International HIV Drug Resistance Workshop


10–14 June 2003, Cabo del Sol, Los Cabos, Mexico


HUMAN β-DEFENSINS INHIBIT HIV-1 REPLICATION IN VITRO

Antivir Ther. 2003; 8:S28 (abstract no. 25)

ME Quiñones-Mateu1,2, MM Lederman2, Z Feng2, B Chakraborty1, J Weber1, HR Rangel1, ML Marotta1, M Mirza1, B Jiang2, P Kiser1, K Medvik2 and A Weinberg2
1Cleveland Clinic Foundation, Cleveland, OH; 2Case Western Reserve University, Cleveland, OH, USA

BACKGROUND: Mechanisms underlying the infrequent transmission of HIV-1 through the oral mucosa are incompletely understood. Here we describe the anti-HIV-1 activity of human β-defensins (hBDs), small cationic innate defence molecules that provide a first line of protection at mucosal surfaces.

METHODS: Recombinant hBD-1, -2, and -3 were generated and used to evaluate their anti-HIV-1 activity and cytotoxicity in PBMC, CEM X4/R5 and Ghost X4/R5 cells. Real-time RT-PCR was used to quantify hBD mRNA expression in normal human oral epithelial cells. Flow cytometric and confocal microscopy analysis was used to determine the effect of hBDs over CCR5 and CXCR4 co-receptors. Finally, the potential interaction between hBDs, cell membrane and viral particles was analysed by immunogold transmission electron microscopy.

RESULTS: HIV-1 induced expression of hBD-2 and -3 mRNA, but not hBD-1, four- to-78-fold above baseline, in normal human oral epithelial cells. HIV-1 failed to infect normal human oral epithelial cell monolayers, even after 5 days of exposure. While recombinant hBD-1 had no antiviral activity, both rhBD-2 and -3 showed a concentration-dependent inhibition of HIV-1 replication without cellular toxicity. This antiretroviral effect was greater against the CXCR4-tropic than against CCR5-tropic HIV-1 isolates. HBD-2 and -3 bound to virions and induced a direct and irreversible effect on virion infectivity, with electron microscopy confirming direct binding of hBDs to viral particle. In addition, hBD-2 and -3, but not hBD-1, induced down-modulation by internalization of the HIV-1 coreceptor CXCR4 (but not CCR5) in peripheral blood mononuclear cells and T-lymphocytic cells, as shown by confocal microscopy and flow cytometric.

CONCLUSIONS: This study shows for the first time that (i) HIV-1 induces hBD expression in human oral epithelial cells; and (ii) hBDs block HIV-1 replication via a direct interaction with virions and through modulation of the CXCR4 co-receptor. These properties may be exploited as new strategies for mucosal protection against HIV-1 transmission.

PRESENTING AUTHOR: ME Quiñones-Mateu

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2003-07-08
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