Peptides in the mouth may prevent people from contracting HIV, say researchers in the Nov. 7 issue of the international journal AIDS.
To determine why the human immunodeficiency virus rarely is contracted through the mouth, Dr. Aaron Weinberg, director of research at the Case Western Reserve School of Dentistry, Cleveland, and colleagues conducted a study to understand the mechanisms underlying the mucosal transmission of HIV.
Since the lining of the mouth is under constant attack by bacteria that live and grow in the mouth, it has a defense line of peptides called human beta defensins-2, or hBD2, and human beta defensins-3, or hBD3. The presence of these peptides in the mouth may prevent humans from getting sick and may promote rapid healing of the mouth from food abrasions or accidental bites to the tongue and mouth.
Researchers found that when HIV was introduced to a single layer of human oral epithelial cells grown in the laboratory, the expression of hBD2 increased by almost 80-fold. In fact, HIV failed to infect these cells even after five days of exposure, which was 72 hours after HIV no longer could live in the conditions found in the mouth.
The discovery suggests that the small peptides produced by cells lining the mouth bind to the viral particles directly and even regulate important receptors the virus uses to infect human cells.
According to Dr. Weinberg, this information could be used to develop medical interventions using natural products, such as those being isolated from the "good oral bugs" that induce hBD2 and hBD3, in other sites of the body that are more susceptible to HIV infection. These products someday also could be used as a coating on catheters, intubation tubes and implants to prevent secondary infections within the body.
