March 26, 2004
University of Alabama-Birmingham (UAB) researchers in Zambia have discovered that HIV in its earliest stages of infection might be especially vulnerable to vaccines. At UAB's clinic in Lasaka, Zambia, health-care workers followed heterosexual couples in which one partner was HIV-positive. Over a five-year period of examining couples at three-month intervals, the scientists found eight new infections in early stages, according to Cynthia Derdeyn of UAB's Department of Microbiology.
In four cases, HIV was transmitted man-to-woman, and in four cases it was transmitted woman-to-man. Derdeyn and co-authors found that newly transmitted viruses were very different from those in people who had HIV for years. New infections showed only one variant of HIV, while long-term infections were marked with several variants. Moreover, the variants in new HIV infections seemed vulnerable.
"They were less shielded with the sugar substance that the virus uses to protect itself from ... antibodies," Derdeyn said, adding that the viruses were particularly vulnerable to antibodies in the blood of the transmitting partner. "So a seemingly vulnerable virus turns out to be the one that's the strongest in establishing new infections," Derdeyn noted.
The report, "Envelope-Constrained Neutralization-Sensitive HIV-1 After Heterosexual Transmission," appeared in Science (2004;26;(5666):2016-2019). The National Institutes of Health and the American Foundation for AIDS Research funded the study.
03.26.04; Dave Parks