HIV-1 virus moves rapidly in the body, and damages the B-cell antibody-producing system in the gut, within days of infection, according to new research.
The study by Centre for HIV/AIDS Vaccine Immunology is the first to examine what happens to B cells in the gut in the earliest stage of HIV-1 infection.
"These new data show that damage to the antibody arm of the immune system begins quickly, within days. We know that by 80 days, half of the generative microenvironments for antibodies within the immune system in the gut are destroyed," said Dr. Barton Haynes, senior author of the study.
The findings could solve one of the big mysteries in HIV-why the B cell, or antibody response, is so slow to arise in the first place and turns out to be so weak after it does, that it is unable to offer any kind of meaningful defence.
B cells that make antibodies against invading microbes are born in the bone marrow, but migrate out and mature in different locations throughout the body.
Some wind up in the intestine and settle in stretches of lymph node-like follicles called Payer's patches, which are found at the bottom of the small intestine, where they wait to rise up against incoming bacteria, viruses, or other pathogens.
"Unfortunately, we found they are no match for HIV-1," said Anthony Moody, a lead author of the study.
For the study, the researchers examined B cells in blood as early as 17 days after viral transmission, and in lymph tissue in the gut beginning at 47 days after transmission in 40 people infected with HIV-1.
They compared their findings with similar tissue from healthy controls, and found that even at the early stage, HIV-1 had already ravaged the gut's B cell arm of the immune system.
The vast majority of the follicles in the Payer's patches had been damaged.
"HIV-1 turns on the immune system, but turns it on in the wrong way. We found that it was churning out all sorts of B cells. Some appeared to be reactive against HIV-1, but others appeared reactive to things like influenza as well as self molecules," said Moody.
Besides, it was found that by as early as 17 days after transmission, HIV-1 decreased the numbers of naive B cells - cells that may have had the potential to mature into potent infection-fighters.
The researchers are hoping that the findings may lead to a successful AIDS vaccine.
The study has been published in the open access journal PLoS Medicine.