Role of human beta-defensins in HIV infection.

Mechanisms of resistance to HIV-1 infection in the human oral cavity are incompletely understood. While salivary components have been implicated in protection, there is growing evidence that human beta-defensins (hBDs), originating in oral epithelial cells, may be playing an important role in the prevention of HIV infection. New antiviral, chemotactic, and immunosurveillance properties are being attributed to hBDs, which are small cationic antimicrobial innate response molecules expressed in mucosal epithelium. Inducible hBDs are always expressed in normal oral epithelium, a property not shared by other mucosal barriers. Data reviewed in this paper demonstrate that: (1) HIV-1 X4 and R5 phenotypes induce hBD-2 and -3 mRNA in normal human oral epithelial cells; (2) hBD-2 and -3 inhibit HIV-1 infection by both viral strains, with greater activity against X4 viruses; and (3) this inhibition is due to a direct interaction with virions and through modulation of the CXCR4 co-receptor. These properties may be exploited as strategies for mucosal protection against HIV-1 transmission.