People who have HIV produce special antibodies that enable them to suppress the virus. In a new study published in Science Immunology, scientists have identified and described the immunological profile of some people with HIV who are better able to resist the effects of the virus.
A person with HIV will experience symptoms that feel like the flu. As the virus spreads through the body, the immune system will launch an attack by HIV antibodies to fight the virus.
In around 45 days, the immune system normally gains control, in a process called seroconversion. In some people, this can take a few months. However, the virus does not go away.
It remains in the body, and it can continue to affect cells and cause damage, because the virus is still active. The virus also mutates as the immune system pursues it.
As the body's immune system becomes weaker, the person is more likely to develop different infections. When a person's body can no longer fight common infections, this is known as AIDS.
Previous research has indicated that monoclonal antibodies, or mabs, can protect against HIV infection in monkeys.
How bNAbs may help to fight HIV
The bodies of some patients who live with HIV naturally produce a type of antibody known as broadly neutralizing antibodies (bNAbs). Scientists believe that any successful vaccine against HIV must be able to induce bNAbs.
A team led by researchers from Duke University in Durham, NC, studied blood samples taken from people with HIV. They selected 51 people with high levels of bNAbs and 51 people with few or no bNAbs.
They found that many of the changes in immune cell function that stem from chronic HIV infection are linked with high bNAb levels.
The variations included:
- Higher levels of autoantibodies - a type of antibody that attacks the patient's own cells
- Lower levels of T cells that regulate the immune system; these T cells were less active
- Higher levels of memory T follicular helper immune cells.
The results suggest that bNAb production may correlate with specific differences in individual immune functions, and that these differences could occur when HIV infection is not kept under control.
Their theory is that in people with this particular immune system profile, the activity of antibody-producing immune cells, known as B cells, could be less restricted.
This could be because these B cells are supported by T follicular helper cells. They may also be hindered by regulatory T cells.
These conditions could make some people more likely to produce protective bNAbs.
A step toward a vaccine?
It is thought that bNAbs may help to suppress the virus in people who have them by neutralizing a number of HIV viral strains. Other people with HIV have different immunological profiles.
While bNAbs cannot completely clear HIV infections in people who already have HIV, scientists hope that the new insights into bNAbs could be a step toward developing a successful vaccine to prevent the virus.
The researchers hope to find a safe way to replicate these qualities in people who do not have HIV infection, through a vaccine. If the bodies of people who do not have HIV can be stimulated to produce bNAbs, this could provide protection from the virus.
This, they believe, could lead to better experimental vaccines that would protect against HIV.
The findings support existing approaches to developing an HIV vaccine. These involve changing a person's immune system so that it can mimic these conditions. This could be achieved by adding boosters, such as adjuvants, to vaccines.
The study was supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. Blood samples were collected with the help of by the Center for HIV/AIDS Vaccine Immunology (CHAVI), which is supported by NIAID.