U.S. scientists seeking a vaccine for the human immunodeficiency virus say a study of HIV antibodies is leading them in a new direction.

The Duke University Medical Center-led researchers said that new direction came from a detailed study of how the most robust antibodies work to block the HIV as it seeks entry into healthy cells.

"Our study clearly showed that we've been overlooking a very important component of antibody function," said S. Munir Alam, associate professor of medicine and lead author of the study.

Alam and Harvard Medical School Assistant Professor Bing Chen said they studied two potentially powerful antibodies against HIV, 2F5 and 4E10. Both of are rare, broadly neutralizing antibodies, meaning they can block a number of strains of HIV, the scientists said.

The researchers found successful docking of the antibody to the HIV outer coat membrane region required antibody attachment to the virus's membrane, which contains lipid.

"This two-step mechanism, not previously appreciated, might extend to antibodies that protect against other viruses," said study co-author Stephen Harrison of Harvard Medical School.

The researchers said they are now designing a vaccine that incorporates a lipid component and design trials are now being conducted on animals.

The findings are detailed in the Proceedings of the National Academy of Sciences. (c) UPI