Our our immune system could provide us with clues on how to deal with the HIV-1 virus thereby paving way for a possible vaccine that could stimulate production of antibodies to deal with the virus.
Researchers say that a process in our body that is meant to prevent us from autoimmune diseases is effectively preventing our immune system from creating antibodies that could neutralise the HIV-1 virus. The finding paves way for better understanding of why our immune system never produces the required antibodies against HIV or produces them at a very late stage in life.
According to researchers, some patients infected with HIV-1 developed what are known as ‘broadly neutralizing antibodies’ or bnAbs, that can protect against a wide variety of HIV-1 strains by recognizing a protein on the surface of the virus called Env. But the patients only develop these antibodies after many years of infection.
Because of 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. At the same time, patients with lupus showed slower rates of HIV-1 infection.
Scientists believe that’s because these autoimmune patients produce self-reactive antibodies that recognize and neutralize HIV-1.
The process by which the body prevents the creation of antibodies that can cause autoimmune disease is known as immunological tolerance.
Researchers wanted to break through that tolerance and stimulate the production of antibodies that could neutralize HIV-1. For that purpose they first tested mice with genetic defects that caused lupus-like symptoms and found that many of these mice produced antibodies that could neutralize HIV-1 after being injected with alum, a chemical that promotes antibody secretion and is often used in vaccinations.
Subsequently they treated normal mice with a drug that impairs immunological tolerance and found that they began producing antibodies capable of neutralizing HIV-1. The production of these antibodies was increased by alum injections.
And if the mice were also injected with the HIV-1 protein Env, they produced potent broadly neutralizing antibodies capable of neutralizing a range of HIV-1 strains.
In every case, the production of these HIV-neutralizing antibodies correlated with the levels of a self-reactive antibody that recognizes a chromosomal protein called Histone H2A. The researchers confirmed these antibodies could neutralize HIV-1.
The study was published in The Journal of Experimental Medicine.