One strategy for developing a highly effective HIV vaccine is to learn how some HIV-infected people naturally develop antibodies that can stop a high percentage of global HIV strains from infecting human cells in the laboratory. These so-called broadly neutralizing antibodies (bNAbs) develop too late to help infected people overcome the virus, but if a vaccine could stimulate uninfected people’s immune systems to make bNAbs, they might protect those people from HIV infection.
Researchers have been studying serial blood samples donated by an HIV-infected South African individual between 15 weeks and 4 years after becoming infected to learn how this person’s immune system developed a powerful bNAb. The scientists previously observed how the bNAb mutated from its earliest, immature form into its final, most powerful HIV-fighting form through interactions with the virus over many months. In new research, the scientists discovered that early in the course of infection, a second, more ordinary HIV antibody influenced the virus to develop a mutation that helped the bNAb develop its broadly neutralizing capability. Thus the process of antibody-HIV co-evolution can involve more than one antibody, a finding that may have implications for HIV vaccine design.