Differences In Infection Routes May Complicate Development.(of AIDS vaccines)

2001 OCT 17 - (NewsRx.com & NewsRx.net) -- by Michael Greer, senior medical writer - HIV infection follows different patterns depending on the means of transmission, which need to be taken into account during vaccine studies, researchers in the United States warn.

"Transmission of human immunodeficiency virus type 1 (HIV-1) is largely a result of heterosexual exposure, leading many investigators to evaluate mucosal vaccines for protection against intravaginal (i.vag.) transmission in macaque models of AIDS," explained Marnix L. Bosch and colleagues at Seattle's School of Public Health and Community Medicine, Washington Regional Primate Research Center, and the University of Washington. "Relatively little is known, however, about the dynamics of viral replication and the ensuing immune response following mucosal infection."

Viral and immune activity shortly after vaginal infection varies substantially that following intravenous infection, Bosch and coworkers found.

The researchers studied the dynamics of simian-human immunodeficiency virus (SHIV) infection in macaques. When SHIV was transmitted to these animals via the vaginal route, they observed faster and more potent mucosal antibody and cytotoxic T lymphocyte responses.

However, peripheral viral activity and immune responses were delayed in vaginally infected animals, Bosch and team noted. Reductions in CD4 cell counts, positive SHIV test results, and peaks in peripheral blood viral RNA levels were seen one week later in these macaques than in those ...