( /p> This second finding provides us ...)AIDS vaccine research offers new insights on survival

"This second finding provides us with an important marker to use in gauging the vaccine's performance," says Letvin. "By measuring the levels of central memory cells in blood samples taken from participants in human clinical trials [to test the AIDS vaccine] scientists would be able to predict how well the vaccine would work over time."

More than 30 million individuals -- a majority in the world's developing nations -- have died of AIDS since it was first identified 25 years ago.

"This research underscores the importance of the preservation of memory CD4+ T cells for the long-term health of the HIV-infected individual," says Letvin. "It also suggests that the measurement of this cell in the blood of vaccinated individuals who subsequently become infected with HIV may provide an important predictor of vaccine efficacy."

Study coauthors include BIDMC investigators Yue Sun, M.D., Darci Gorgone, M.A., Adam Buzby, A.B., Jorn Schmitz, M.D., and Brianne Barker, A.B.; John Mascola, M.D., Ling Xu, M.D., Zhi-yong Yang, M.D., Bimal Chakrabarti, M.D., Srinivas Rao, D.V.M., Ph.D., and Gary Nabel, M.D., Ph.D., of the NIAID VRC; David Montefiori, Ph.D., of Duke University Medical Center; and Fred Bookstein, Ph.D., of the University of Washington, Seattle and the University of Vienna, Austria.