AIDS virus hides out in “accomplice” cells

TORONTO (Reuters) – The AIDS virus has an accomplice that
helps it infect the immune system cells it attacks — other
immune system cells, U.S. researchers reported on Saturday.

In fact, these other cells, known as B cells, may be key to
infection, the University of Pittsburgh researchers told an
international AIDS conference. “The research supports a new
role for B cells in the development and spread of HIV between
cells,” said Dr. Charles Rinaldo, who led the study.

The findings may help find a way to block infection, and
help explain why the virus can hide out in “reservoirs” inside
the body for decades.

The AIDS virus is especially hard to fight because it
infects the immune system. It favors cells called CD4 T-cells.

It gets into the cells using two molecular doorways, called
receptors. They are CD4 and either CCR5 or CXCR4 and are found
only on T-cells.

Other immune cells were thought to be uninvolved. But
Rinaldo’s team found that other immune cells called B cells
make a protein called DC-SIGN that seems necessary for HIV to
ever infect a cell.

The researchers looked at B cells from 33 healthy subjects
and 20 adult patients with HIV. About 8 percent of these cells
expressed, or made, DC-SIGN.

One study showed that B cells harbored viruses that could
be transmitted to T cells for as long as two days. HIV had
little effect on the T cells when B cells were not around.

The researchers found a compound that blocks DC-SIGN.

When they blocked DC-SIGN in B cells, and put them in with
T-cells in a lab dish, the virus was unable to infect the
T-cells, the researchers said in a statement to be presented
more fully at the 16th International Conference on AIDS being
held in Toronto.

There is no cure for the AIDS virus, which infects about 40
million people globally and has killed 25 million since it was
first noted in the early 1980s. There is also no vaccine.

Drugs can help control it but the virus cannot be
eradicated from the body. Understanding how it infects cells
may help scientists discover how to clear it from the body or
prevent infection in the first place.

(For more stories related to the International AIDS
Conference, please go to

http://today.reuters.com/news/globalcoverage.aspx?type=aids&src=

GLOBALCOVERAGE_wire)