Case Researchers Discover the Mouth's Defenses Against AIDS; New Findings Hold Potential for New Aids Prevention

CLEVELAND -- Researchers at Case Western Reserve University and the Cleveland Clinic have discovered a way that the mouth may prevent the contraction of HIV. The findings are reported in the new issue of the international journal AIDS. The researchers also added that the findings hold potential for finding new ways of preventing AIDS and other infections in the body.

With the lining of the mouth constantly under attack by a barrage of bacteria that commensally lives and grows in the mouth, the lining of the oral cavity has put up an innate and formidable defense line of peptides called human beta defensins 2 and 3 (hBD2 and hBD3) that may prevent humans from getting sick and may promote rapid healing from food abrasions or accidental bites to the tongue and mouth.

"It is the unique properties of the good bugs found in the mouth that are inducing the expression of hBD2 and 3," stated Aaron Weinberg, director of research at the Case School of Dentistry. The study, titled "Human Epithelial Beta Defensins 2 and 3 Inhibit HIV-1 Replication," was the result of a 12-member research team, including Michael Lederman, an internationally known AIDS researcher from the Case School of Medicine, and Miguel E. Quinones-Mateu, the first author on the paper and a virologist from the Lerner Research Center at the Cleveland Clinic Foundation. Their recent discovery, which went on the fast track for publication in AIDS is the result of funding from a National Institute of Health-funded study on oral defenses against AIDS, of which Dr. Weinberg is the principal investigator.

The discovery suggests that the small peptides produced by cells lining the oral cavity bind to the viral particles directly and can even regulate important receptors the virus uses to infect human cells.

Since the 1990s, Aaron Weinberg, a dentist and microbiologist at the Case School of Dentistry, has been studying the natural defenses found in the mouth and how they react to bacteria and viruses. The discovery was driven by Weinberg's curiosity about the knowledge that HIV, which leads to AIDS, is rarely contracted through the mouth.

While human beta defensins, particularly hBD-1, are found throughout the body's skin and epithelial cells to ward off general infections, it was hBD2 and hBD3 in the normal lining of the mouth that responded to HIV.

Weinberg noted that hBD2 increased by almost 80 fold in the presence of HIV introduced to a monolayer of human oral epithelial cells grown in the lab and maintained their response rate for 72 hours-long after the time the virus could live in the conditions in the mouth.

Information gained from the study, according to Weinberg, has the potential to develop new medical interventions using natural products, such as those being isolated from the "good oral bugs" that induce hBD2 and 3, in other sites of the body that are more susceptible to HIV infection. These products also have the potential as a coating on catheters, intubations and implants to prevent secondary infections within the body, which result in annual health care costs of over $15 billion.

Source: Case Western Reserve University