Immune system process found to prevent generation of antibodies capable of neutralising HIV-1 virus

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13 July 2017

Researchers from the University of Colorado School of Medicine have discovered that a process that protected the body from autoimmune disease also prevented the immune system from generating antibodies capable of neutralising the HIV-1 virus.

The findings, published on Tuesday in The Journal of Experimental Medicine, may be considered by scientists trying to develop a vaccine that could stimulate the production of these neutralising antibodies.

Some patients infected with HIV-1, the virus that caused AIDS, developed "broadly neutralizing antibodies" (bnAbs) capable of protecting against a wide variety of HIV-1 strains by recognising a protein on the surface of the virus called Env.

However, the antibodies developed in the patients' bodies after years of infection. Researchers were keenly studying how such bnAbs could be induced quickly in response to vaccinations against HIV-1.

bnAbs had a number of unusual features, including the fact that some of them often also recognised a number the body's own proteins. Individuals infected with HIV-1 might, therefore, take a long time to develop these antibodies as their production was suppressed by some of the mechanisms that prevented the body from generating self-reactive antibodies that could target healthy tissues and cause autoimmune diseases such as systemic lupus erythematosus (SLE).

Due to shared features found in a number of HIV-1 bnAbs, scientists suspected the inability or delayed ability to make these type of protective antibodies against HIV was due to the immune system suppressing production of the antibodies to prevent the body from creating self-reactive antibodies that could cause autoimmune diseases like systemic lupus erythematosus.

"We wanted to see if people could make a protective response to HIV-1 without the normal restraint imposed by the immune system to prevent autoimmunity," shared Raul M Torres, PhD, professor of immunology and microbiology at the University of Colorado School of Medicine, ANI reported.

The process, which allowed the body to prevent the creation of antibodies that could cause autoimmune disease is known as immunological tolerance.

Torres wanted to break through that tolerance and stimulate the production of antibodies that capable of neutralising HIV-1.

In tests with mice having genetic defects that caused lupus-like symptoms, the researchers found that many of them produced antibodies that could neutralise HIV-1 after being injected with alum, a chemical that promoted antibody secretion and was often used in vaccinations.





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