"This research suggests that a novel approach to HIV therapy targeting a stable component of HIV might be feasible," says NIAID Director Anthony S. Fauci, M.D.
The phenomenon, called RNA silencing, was detected first in plants and later in insects. Although plants and insects lack the sophisticated immune defenses of higher organisms, they nevertheless successfully battle viruses by detecting, and then silencing, viral genetic material. Silencing leads to the destruction of viral RNA. Viruses, however, are not permanently defeated because they have evolved ways to suppress the silencing action.
Until now, scientists have not had clear evidence that RNA silencing plays a role in the defensive repertoire of mammals and other vertebrates. Dr. Jeang and his colleagues set out to determine if RNA silencing (also called RNA interference or RNAi) contributes to human cells' defense against HIV.
They asked three questions. First, does HIV have genetic sequences that an HIV-infected cell can detect and transform into the necessary precursors of RNAi, called short interfering RNA (siRNA)? Second, do human cells use siRNAs to disable HIV? Third, if human cells try to battle HIV using RNAi, does HIV have a way to evade the defensive maneuver? The answer to all three questions, the scientists determined, is yes.
The most unexpected finding, according to Dr. Jeang, was the way HIV uses one of its prote
Contact: Anne A. Oplinger
NIH/National Institute of Allergy and Infectious Diseases