Canada: The Herpes-HIV Connection; McMaster University Professor Leads AIDS Conference Panel Exploring Risk Factors

On Wednesday at the 16th International AIDS Conference, scientists gathered for a session led by a McMaster University researcher to examine the role of mucous immunity in the fight against AIDS.

Dr. Ken Rosenthal, head of the viral vaccines division of Center for Gene Therapeutics at McMaster's Michael DeGroote School of Medicine, is part of worldwide group of scientists seeking to study the potential for innate immunity protection in the mucous membranes -- the moist tissue lining genital tract, lungs and digestive system. Different from the immunities acquired over a lifetime, said Rosenthal, innate immunities are primitive. Humans share these with fruit flies, earthworms and even plants.

"It turns out, the vast majority of our immune cells are located in the mucous membranes of our bodies, because that's where most of the pathogens, or infectious agents, enter," said Rosenthal, who chaired the session along with Dr. Mario Clerici of Italy.

Researchers have recently discovered that regardless of how HIV enters the body -- whether through sexual transmission or IV drug use -- the virus immediately targets and destroys the mucosal immune system. "More than anything, this reinforces the argument that we've got to have a much better understanding of mucosal immunity and how it works, because this is the target tissue that we have to protect," Rosenthal said.

University of Toronto researcher Dr. Rupert Kaul shared his data on the link between herpes and HIV. Infection with herpes increases the number of HIV-susceptible target cells in the genital tract. North Americans infected with herpes simplex virus type 2 face three times the risk of contracting HIV, while Africans who are infected with the herpes type 2 virus are at 10 times the risk of contracting HIV. Up to 70 percent of people in some areas of Africa are infected with the herpes virus.

McMaster and University of Manitoba scientists discussed their data on African sex workers who, while exposed to HIV, have not contracted it. These HIV-resistant women appear to have a different innate immune response than the sex workers who became infected.