Antibody response found to reduce mother-to-child HIV transmission
The third variable loop, a previously discounted region of the HIV virus envelope, has been identified to have a strong antibody response, which according to a recent study, could reduce the risk of HIV transmission from mother to child.
“Our current study raises the hypothesis that temporary augmentation and placental transfer of [third variable loop] autologous virus neutralizing antibodies in HIV-1-infected pregnant women may be a plausible strategy to further reduce peripartum transmission of HIV-1,” Sallie R. Permar, MD, PhD, associate professor of pediatrics at Duke University, and colleagues wrote in a study published in the Journal of Clinical Investigation.
Researchers analyzed data from the Women and Infants Transmission Study, a study conducted in the 1990s before the implementation of AZT treatment for HIV. A group of 83 untreated HIV transmitting mothers was compared with a group of 165 untreated HIV infected non-transmitting mothers. Both groups were restricted to non-breastfeeding and untreated mothers to eliminate these two important modifiers of mother-to-child transmission.
The study found that maternal envelope third variable loop-specific IgG antibody responses predicted a reduced risk of mother-to-child transmission (OR = 0.64; 95% CI, 0.42-0.97, P = .04). The study also found that recombinant maternal third variable loop specific IgG monoclonal antibodies helped to neutralize autologous HIV-1 isolates.
“Common V3-specific antibody responses in maternal plasma predicted reduced risk of [mother-to-child transmission] and mediated autologous virus neutralization,” the researchers wrote.
The researchers noted that these results suggest that boosting maternal third variable loop antibody responses may be effective at reducing the transmission of HIV from mother to child. However, further research is needed to determine the effectiveness of boosting these antibody responses in HIV vaccines.
Permar said in a press release that she found these results “very surprising, because this type of weak neutralizing antibody response, which had previously been thought to be inconsequential for HIV transmission, could potentially be effective in preventing mother-to-child transmission. And there are current HIV vaccine candidates, such as recombinant HIV envelope protein immunization, in early-stage clinical testing that can elicit this type of response."– by David Costill
Disclosure: The researchers report no relevant financial disclosures.