Anti-HIV agent is found in tears and saliva

Scientists have discovered a natural protein found in tears and saliva that is a powerful anti-HIV agent, a finding that could open up entirely new treatments for AIDS.

The research solves a longstanding mystery about a substance in the urine of pregnant women known since 1922 to be a powerful anti-bacterial agent. This substance is also able to destroy HIV, and the findings have helped to explain why AIDS cannot be transmitted through saliva.

Scientists from the New York University School of Medicine and from the National Institutes of Health were involved in an intensive search for the powerful anti-AIDS and anti-cancer agent present in the urine of pregnant women.

They discovered two agents, lysozyme, an enzyme first described by the discoverer of penicillin, Dr Alexander Fleming, that breaks down the cell wall of bacteria causing them to die, and ribonucleases. These are enzymes that can break apart the genetic material of RNA viruses such as the AIDS virus.

Lysozyme is abundant in tears and saliva and is produced at high levels during pregnancy. "These proteins are very promising anti-AIDS agents and likely will be well tolerated by the body, causing few side effects because they occur naturally," according to Prof Sylvia Lee-Huang of NYU. The researchers have yet to discover how they work against HIV, but their work, described in the current issue of the Proceedings of the National Academy of Sciences, suggests that the lysozyme and ribonuclease enzymes act together to inhibit the virus.