HIV Can Emit Protein That Inhibits Immune Cells, Scientists Say

The AIDS virus can inhibit the body’s killer immune cells from attacking, according to a team of scientists who say it’s a “formidable” trick by an already elusive destroyer.

Scientists long have known the AIDS virus escapes destruction by keeping one step ahead of the body’s disease-fighting cells. Now a team of scientists studying the immune response of four patients have uncovered the human immunodeficiency virus’s ability to block those cells from doing their job.

They reported their findings Friday in the journal Science.

Normally, the body’s killer immune cells, called cytotoxic T lymphocytes or CTLs, sniff out disease and destroy it.

They’re switched on by the presence of a disease protein, which triggers the CTL to forever recognize the disease and attack it on sight.

In theory, CTLs ought to be able to destroy the AIDS virus during early infection. But they don’t, primarily because the HIV constantly mutates, changing its appearance so the CTLs have to recognize it all over again before they know to attack.

Now the research team from Oxford, England, has discovered a second HIV escape mechanism. It can emit a piece of protein that, instead of switching on CTLs, inhibits their ability to kill anything, reported lead author Ute-Christiane Meier of John Radcliffe Hospital.

This protection “might exceed the advantage conferred by simple . . . escape,” Meier concluded.

Several other viruses perform this trick, but scientists hadn’t suspected it was happening in HIV, said Dr. Anthony Fauci of the U.S. National Institutes of Health.

“What’s described here is something even more formidable,” he said. “But it’s too early to say if the finding has any implications for HIV treatment.”