The finding by researchers from the Fred Hutchinson Cancer Research Center may provide insight to developing an HIV-1 vaccine, which offers protection against various circulating strains.
Senior researcher, Julie Overbaugh commented:
"We found that women who had been infected twice not only had more potent antibody responses, but some of these women had 'elite' antibody activity, meaning that they had a broad and potent ability to neutralize a wide variety of strains of HIV over a sustained period time."
According to estimations, only 1% of HIV-infected people are "elite neutralizers", which means they are able to potently neutralize multiple subtypes of the virus.
The team tracked the immune activity of 12 superinfected women from Mombasa, Kenya, over a five-year period and compared each woman to a control group of three women who were infected with a single strain of the HIV virus. By evaluating the ability of antibodies to neutralize a range of circulating HIV-1 variants in both groups, the team was able to establish what impact two viruses had on immune response compared to one virus.
After accounting for variables, including antibody response prior to superinfection and biomarkers of immunity like CD4+ T cell count and viral load, the findings indicate that having a mixture of different viral strains may be one approach to encourage a robust antibody response.
Furthermore the study results show that in addition of achieving stronger response rates in superinfections, they also lead to a more rapid response that has the ability of identifying many other HIV strains.