EGPAF Award Recipient Presents Research Toward Eliminating Mother-to-Child Transmission

This week in Cape Town, South Africa, the first HIV Research for Prevention (HIVR4P) Conference became the major venue for global HIV vaccine, microbicide, and additional HIV prevention research. During the conference, Susie Zeegen Postdoctoral Award recipient Lindsay Wieczorek, Ph.D.,  presented her research evaluating the role of neutralizing antibodies (NAb) in mother-to-child transmission of HIV. NAb are an essential component of our immune response against HIV and other disease-causing pathogens. In fact, most successful vaccines against diseases such as measles and influenza rely on these antibody responses to protect us from disease.

Understanding how mother-to-child transmission of HIV happens or is prevented in the absence of anti-HIV drugs is still a topic of important research, more than 30 years since HIV was discovered as the cause of AIDS. We do know that an HIV-positive pregnant woman has a 40% chance of transmitting HIV to her baby, either in utero, during the birth process, or during breastfeeding. Amazingly, 60% of infants born to HIV-positive women will not become infected, despite being exposed to HIV during pregnancy and breastfeeding. Why? We don't really know.

One possibility is that NAb against HIV play a role in protecting the infant from infection. Anti-HIV NAb develop over time in HIV-infected individuals and are present in HIV-positive pregnant women. These antibodies can also be transferred to the infant in utero and during breastfeeding. The role of maternal NAb in the protection of infants from infection is being debated, with some research pointing towards a protective role, and other research showing no effect or even an increase in possible infection.

In the project presented at HIVR4P, Dr. Wieczorek and her team looked at the anti-HIV NAb response in Thai mothers who transmitted HIV to their infants versus those who did not. They found that mothers with NAb responses against HIV were more likely to have transmitted HIV than mothers that did not have these antibodies. What is not known, however, is whether these NAb responses could act against the virus that was present in the mother and, thus, the virus transmitted to the infant. Because transmission took place even in the presence of these NAb, the likely answer is that the NAb were not effective against the transmitted virus.

So where does this leave us? Clearly, the role of anti-HIV NAb in the transmission of HIV from mother-to-child (or prevention thereof) is still being debated. Answering this question definitively will be a critical part of the search for a successful vaccine against HIV.

Hats off to Dr. Wieczorek and her team for moving in that direction!

Lindsay Wieczorek, Ph.D., a scientist at the U.S. Military HIV Research Program (MHRP), investigates the link between the body’s natural immune response to HIV and maternal-to-child transmission. A graduate of the University of Wisconsin, Johns Hopkins University, and Catholic University, Lindsay was recently given the Susie Zeegen Fund Postdoctoral Award, named for Susie Zeegen, one of the co-founders of the Elizabeth Glaser Pediatric AIDS Foundation.

Jeff Safrit, Ph.D., is EGPAF's Director of Clinical and Basic Research, and is based in Los Angeles, CA.