HIV Research Today is a free monthly online journal that collates and summarizes the latest research about HIV, including details on human immunodeficiency virus, testing, treatment, prevention, vaccines, aids.

A fusion-intermediate state of HIV-1 gp41 targeted by broadly neutralizing antibodies.

Frey G, Peng H, Rits-Volloch S, Morelli M, Cheng Y, Chen B

Laboratory of Molecular Medicine, Children's Hospital, and Department of Pediatrics, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA.

Most antibodies induced by HIV-1 are ineffective at preventing initiation or spread of infection because they are either nonneutralizing or narrowly isolate-specific. Rare, "broadly neutralizing" antibodies have been detected that recognize relatively conserved regions on the envelope glycoprotein. Using stringently characterized, homogeneous preparations of trimeric HIV-1 envelope protein in relevant conformations, we have analyzed the molecular mechanism of neutralization by two of these antibodies, 2F5 and 4E10. We find that their epitopes, in the membrane-proximal segment of the envelope protein ectodomain, are exposed only on a form designed to mimic an intermediate state during viral entry. These results help explain the rarity of 2F5- and 4E10-like antibody responses and suggest a strategy for eliciting them.

Published 12 March 2008 in Proc Natl Acad Sci U S A, 105(10): 3739-44.
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