HIV Immune Response Influenced by Gut Flora
Durham, NC – Normal microorganisms in the intestines appear to play a pivotal role in how the HIV virus foils a successful attack from the body’s immune system, according to new research from Duke Medicine.
The study, published today, in the journal Cell Host & Microbe, builds on previous work from researchers at the Duke Human Vaccine Institute that outlined a perplexing quality about HIV: The antibodies that originally arise to fight the virus are ineffective.
These initial, ineffective antibodies target regions of the virus’s outer envelope called gp41 that quickly mutates, and the virus escapes being neutralized. It turns out that the virus has an accomplice in this feat - the natural microbiome in the gut.
“Gut flora keeps us all healthy by helping the immune system develop, and by stimulating a group of immune cells that keep bacteria in check,” said senior author Barton F. Haynes, M.D., director of the Duke Human Vaccine Institute. “But this research shows that antibodies that react to bacteria also cross-react to the HIV envelope.”
Haynes said the body fights most new infections by deploying what are known as naïve B cells, which then imprint a memory of the pathogen so the next time it encounters the bug, it knows how to fight it.
But when the HIV virus invades and begins replicating in the gastrointestinal tract, no such naïve B cells are dispatched. Instead, a large, pre-existing pool of memory B cells respond – the same memory B cells in the gut that fight bacterial infections such as E coli. Continue>
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