Photo by Fatima Tayag / image courtesy of Dr. Julie Overbaugh
Yesterday HIV researcher Dr. Julie Overbaugh, who holds the Endowed Chair in Graduate Education at Fred Hutchinson Cancer Research Center, delivered the 2018 Bernard Fields Lecture, which kicked off the annual Conference on Retroviruses and Opportunistic Infections held this year in Boston. Overbaugh focused her talk on the power of international collaboration to prevent HIV infection by detailing the results from a six-year study designed to assess the risk of mother-infant HIV transmission through breast milk.
“The trial revealed risk and correlates of breast milk transmission, as was its original intent, but the data and samples from that trial were instrumental in revealing unique aspects of the infant immune response,” Overbaugh said during the lecture.
The link between breast-feeding and HIV transmission
In 1992, Overbaugh teamed up with Dr. Ruth Nduati at the University of Nairobi and Dr. Joan Kreiss at the University of Washington to study whether breast-feeding raises the risk of HIV transmission from mother to infant. Formula feeding posed clear health risks to infants, particularly in areas where mothers could not access clean water, and the World Health Organization recommended breast-feeding over formula-feeding, even for mothers infected with HIV-1. At the time, the risk of HIV transmission through breast milk was unclear, and antiretroviral drugs that could prevent mother-child transmission were not yet available. Overbaugh’s lab supported the study by developing assays to detect HIV subtypes circulating in Kenya.
The team found that breast-feeding doubled the risk of HIV transmission from mother to child. Though collected decades ago, the samples from study are still providing insights that may help inform HIV vaccine design.
Further work from Overbaugh’s group suggests that maternal antibodies which facilitate antibody-dependent cellular cytotoxicity of HIV-infected cells may have a protective effect, and it has shown that infants can generate broadly neutralizing antibodies against HIV much more rapidly than adults. Perhaps most importantly, broadly neutralizing antibodies from infants have acquired their neutralization capabilities with fewer immunoglobulin gene modifications than those from adults. This finding could provide insights that help scientists design HIV vaccines that stimulate adults to produce a broadly neutralizing response more quickly than natural infection.
Overbaugh also discussed an HIV variant found in a specific infant from the Nairobi breast-feeding trial, BG505. The infant produced a broad neutralizing antibody response to the infection. HIV’s envelope protein studs the outside of the virus in groups of three, known as “trimers.” The envelope protein from this infant’s HIV variant has been widely studied by researchers seeking a better understanding of how HIV’s structure contributes to its infectivity and ability to stimulate an immune response.
“It’s been very exciting to see how the field has landed on one virus from this trial … and that this BG505 trimer is advancing [HIV] vaccine research at a rapid pace,” she said.
Lessons learned from 25 years of collaboration
Overbaugh also touched on what she’s learned from her 25 years of international collaboration, particularly the lessons most relevant to young investigators.
“There are great opportunities for collaboration in science, you just have to jump in and see if they’re right for you,” she said. “It’s also been my experience that there’s value in having a clinical and an international perspective as a basic scientist studying HIV. … [My collaborators] reminded me that the study of the fascinating aspects of HIV is best blended with a focus on our end goal, which is to prevent, treat and cure HIV.
“It’s also really just fun to be part of a supportive, long-term collaborative team,” she added. “As somebody who came from a working-class family and a small town, I never expected to have the experiences and the opportunities I’ve had. Nor did I expect to develop the friendships I’ve developed as part of this collaboration.”
The annual Bernard Fields Lecture honors Dr. Bernard N. Fields, a virologist and leader in the field of molecular pathogenesis, who passed away in 1995. In 1994, Fields wrote a Nature commentary that called for AIDS researchers to turn to basic science and “reinvigorated the research agenda and NIH funding policies in HIV and AIDS,” said Dr. Douglas Richman, a virologist at the University of California, San Diego and director of the UC San Diego HIV Institute, who introduced the Bernard Fields Lecture.
“We honor Bernie’s example with an annual award to an investigator who has made major contributions to basic and translational research in HIV,” said Richman, who described Overbaugh as the “ideal” Bernard Fields awardee. Her lecture and slides can be viewed on the CROI site.
Sabrina Richards, a staff writer at Fred Hutchinson Cancer Research Center, has written about scientific research and the environment for The Scientist and OnEarth Magazine. She has a Ph.D. in immunology from the University of Washington, an M.A. in journalism and an advanced certificate from the Science, Health and Environmental Reporting Program at New York University. Reach her at firstname.lastname@example.org.
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