HIV Antibodies in Body Could Lead to Vaccine

(CN) — People living with HIV but whose bodies neutralize the virus may have special immunological profiles that could be used to develop better vaccines to protect against the virus, according to new research.

While the neutralizing antibodies called bNAbs cannot fully clear HIV infections in people who have already contracted the virus, many health experts believe that inducing bNAbs is critical to a successful preventative HIV vaccine.

The findings support approaches to developing an HIV vaccine that involve modifying an individual's immune system to mimic the conditions of individuals with high levels of bNAbs, using vaccine boosters known as adjuvants.

The team's work, published Friday in journal Science Immunology, indicate that bNAb production may be associated with specific variations in individual immune functions, which may be triggered by unchecked HIV infection.

The findings supports approaches to developing an HIV vaccine that involve modifying an individual's immune system to mimic these conditions through the addition of vaccine boosters, known as adjuvants.

Using blood samples collected by the National Institute of Allergy and Infectious Diseases-supported Center for HIV/AIDS Vaccine Immunology from people living with HIV, the researchers analyzed the samples' variations in immune-regulatory T cells, which moderate the immune system, memory T follicular helper immune cells — required for the generation of long-lived humoral immunity — and bNAb levels.

The team compared blood samples from the 51 individuals with the highest level of bNAbs with samples from 51 individuals with few or no bNAbs present, highlighting specific immunological variations that may indicate potential research paths toward ultimately developing an effective vaccine.

Specific differences included a higher frequency of antibodies that attack one's own cells called autoantibodies; fewer immune-regulatory T cells, which were less active in individuals with high levels of bNAbs; and a higher frequency of memory T follicular helper immune cells.

The team believes that the activity of antibody-producing immune cells, or B cells, may be less restricted because they are assisted by T follicular helper cells and may be obstructed by regulatory T cells. Such an immune system configuration could lead to more efficient production of protective bNAbs against HIV.

"New vaccination strategies for amplifying antibody responses by transiently limiting immune tolerance controls of antibody responses to bNAb epitopes (the part of an antigen model that an antibody attaches itself to) may be needed. Such vaccination strategies are already being tested in the setting of cancer vaccines to augment host anticancer T cell responses," the study says.

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