( se cells. It doesn't give us the whole ...)HIV-1 kills immune cells in the gut that may never bounce back

se cells. It doesn't give us the whole picture," Markowitz says. "But if we actually go into tissue, we see something different. What we see there is eye-opening." After three years of intensive drug therapy that suppresses HIV replication very effectively, most patients still had only half the normal number of CD4+ effector memory T cells in their GI tracts.

"Obviously the first question is, why" What's the mechanism"" Markowitz says.

A second paper, published online in the Journal of Virology, makes some headway toward an answer. By examining the viral burden of DNA and RNA in cells from the GI tract, and comparing that to cells from the peripheral blood, Markowitz, Mehandru and their collaborators determined that the mucosal lining of the GI tract carried a disproportionately heavy viral load. That means that the initial loss of CD4 T cells in that area is partially due to virus activity. But the researchers also found evidence suggesting that there are at least two more ways in which the cells were being killed off. Some of the T cells self-destruct (a process called activation-induced cell death or apoptosis), while some appear to be killed by other cytotoxic immune cells.

"These papers speak strongly to HIV pathogenesis, to HIV therapy, and to understanding how the host and virus interact," Markowitz says. However, the short and long term consequences of the persistence of this depletion remain unknown.

In the clinic, if the loss of CD4 T cells in the GI tract translates into increased incidence of colonic polyps or colorectal cancer, routine monitoring practices will have to be re-examined, with HIV-positive patients receiving colonoscopies earlier and perhaps more frequently than current recommendations allow. In the laboratory, these findings should give researchers another angle with which to approach HIV vaccines.

"What good is a vaccine going to be if you get immune responses in peripheral blood but t
'"/>

Source:Rockefeller University

Page: 1 2 3
Related biology news :

1. Research advances quest for HIV-1 vaccine
2. HIV-1 spread through six transmission lines in the UK
3. Ancient immune defense mechanism is no match for HIV-1
4. UAB researchers confirm HIV-1 originated in wild chimpanzees
5. HIV-1s high virulence might be an accident of evolution
6. Human testis harbors HIV-1 in resident immune cells
7. Researchers discover new details about HIV-1 entry and infection
8. Study: Harmless virus kills some cancers
9. VCU study shows hormone-like molecule kills cells that cause inflammation in allergic disease
10. Scientists develop nanotech-laser treatment that kills cancer cells without harming healthy tissue
11. Restoring silenced suppressor gene kills lung-cancer cells