Herb used in Chinese therapy may help fight AIDS

New Delhi, Dec 22 (PTI) A herb used in Chinese therapy
may provide succour to HIV patients as well as help in other
immuno-deficiency and age-related diseases, according to
researchers.

"The ability to enhance telomeric activity and
anti-viral functions of CD8 T-lymphocytes suggests that this
strategy could be useful in treating HIV disease, as well as
immuno-deficiency and increased susceptibility to other viral
infections associated with chronic diseases or aging," a
researcher said in a study conducted at UCLA AIDS Institute,
Los Angeles.

The study has found that a chemical from the
astragalus root, often used in Chinese herbal therapy, can
prevent or slow the progressive telomere shortening, which can
make it a key weapon in the fight against AIDS.

"This has the potential to be either added to or
possibly even replace the HAART (highly active antiretroviral
therapy), which is not tolerated well by some patients and is
also costly," said study co-author Rita Effros, a professor of
pathology and laboratory medicine at the David Geffen School
of Medicine at UCLA and member of the AIDS Institute.

Like other kinds of cells like immune cells lose the
ability to divide as they age because a part of their
chromosomes known as a telomere becomes progressively shorter
with cell division. As a result, the cell changes in many
ways, and its disease fighting ability is compromised.

The study, to be published in Journal of Immunology,
says a great deal of cell division must take place within the
immune system for the system to function properly. For
example, the so-called "killer" CD8 T-cells that help fight
infection have unique receptors for particular antigens. When
a virus enters the body, it is recognised by receptors of the
T-cells, which create through division versions of themselves
that fight the invader.

Generally, the telomeres in cells are sufficiently
long that they can divide many times without a problem.
Moreover, when fighting infections, T-cells can turn on an
enzyme called telomerase, which can prevent the telomeres from
shortening.

"The problem is that when we're dealing with a virus
that can't be totally eliminated from the body, such as HIV,
the T-cells fighting that virus can't keep their telomerase
turned on forever," Effros said. "They turn off, and telomeres
get shorter and they enter this stage of replicative
senescence."

Previous studies have shown that injecting the
telomerase gene into T-cells can keep the telomeres from
shortening, enabling them to maintain their HIV-fighting
function for much longer. This gene-therapy approach, however,
is not a practical way to treat the millions of people living
with HIV.

For the present study, rather than utilising gene
therapy, the researchers used a chemical called TAT2, which
was originally identified from plants used in traditional
Chinese therapy and which enhances telomerase activity in
other cell types. PTI