Immune system may prevent body from neutralizing HIV-1, researchers say

Immunological tolerance -- preventing the creation of antibodies that cause autoimmune diseases -- is thought to be why the body cannot fight the virus.
By Amy Wallace  |  July 11, 2017 at 4:04 PM
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July 11 (UPI) -- A study at the University of Colorado found the process protecting the body from autoimmune disease may also prevent it from creating antibodies against HIV-1.

The study, published July 11 in the Journal of Experimental Medicine, may lead to a possible vaccine that stimulates the production of antibodies to neutralize the HIV-1 virus.

Some patients infected with HIV-1 develop broadly neutralizing antibodies, or bnAbs, that protect against a variety of HIV-1 strains by recognizing a protein on the surface of the virus called Env, which develops after several years of infection.

Researchers theorize that because of shared features of HIV-1 bnAbs, there is an inability to make the protective antibodies against HIV because the immune system suppresses their production -- which prevents the body from creating self-reactive antibodies that cause autoimmune diseases like systemic lupus erythematosus.

However, patients with lupus have slower rates of HIV-1 infection, which could be caused by self-reactive antibodies that recognize and neutralize HIV-1.

This process is known as immunological tolerance, and researchers used mice with genetic defects of lupus-like symptoms to test their theory.

"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," Raul M. Torres, professor of immunology and microbiology at the University of Colorado School of Medicine, said in a press release.

The study found the production of HIV-neutralizing antibodies correlated with levels of a self-reactive antibody that recognizes the chromosomal protein Histone H2A.

"We think this may reflect an example of molecular mimicry where the virus has evolved to mimic or look like a self protein," Torres said, adding that this could explain the difficulty in developing a vaccine for HIV-1.

"But breaching peripheral immunological tolerance permits the production of cross-reactive antibodies able to neutralize HIV-1."

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