Washington, Jan 31 (IANS): In what could lead to a cure for HIV, researchers have found that the human immunodeficiency virus may stay hidden for years in certain "quiet" immune cells.

Drugs for HIV have become adept at suppressing infection, but they still can not eliminate it because the medication in these pills does not touch the virus' hidden reserves, which lie dormant within infected white blood cells, the researchers said.

"It has recently been shown that infected white blood cells can proliferate over time, producing many clones, all containing HIV's genetic code. However, we found that these clones do not appear to harbour the latent reservoir of virus," said study author Lillian Cohn from Rockefeller University.

"Instead our analysis points to cells that have never divided as the source of the latent reservoir," Cohn said.

HIV belongs to a family of viruses that insert themselves directly into the host cell's genome where they can hide out quietly after the initial infection.

HIV mostly targets CD4 T lymphocytes, a type of T cell involved in initiating an immune response.

When HIV integrates itself into the genetic code of a CD4 T cell, it may produce an active infection.

"If a patient stops taking antiretrovirals, the infection rebounds. It is truly amazing that the virus can give rise to AIDS 20 years after the initial infection," Cohn said.

The reservoir of latent virus may be hiding out in a type of CD4 T cell: long-lived memory cells that help the immune system remember particular pathogens, the researchers pointed out.

The study appeared in the journal Cell.