May 18, 2005
Scientists have discovered the gum tissue, or mucosa, in our mouths is naturally resistant to infection by the human immunodeficiency virus type I, or HIV-1. What remains to be more fully determined is exactly how the oral mucosa blocks the virus, information that will be useful in devising new ways to thwart HIV infection. In the May issue of the Journal of Virology, NIDCR grantees demonstrated in oral epithelial cells that HIV-1 stimulates the production of the secretory leukocyte protease inhibitor, or SLPI, which is present in various human secretory fluids. In fact, within one hour of the cells’ exposure to HIV-1, they detected a 50-fold increase in SLPI gene transcripts and soon thereafter a significant increase in SLPI protein in most experiments. The scientists say their data suggest HIV’s spike-like surface protein gp120 interacts with undetermined components on the surface of the epithelial cells, triggering an internal signaling cascade that prompts the SLPI gene to be expressed. This finding is particularly interesting because previous studies with human saliva have shown that SLPI blocks HIV-1 infections of immune T cells and macrophages.
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