From the Vaccine Research Center (R.L.W., A.H.I., N.M.B., M.H., M.R.G., C.B., L. Strom, S.F.A., L.A.H., F.M., I.J.G., L.T.W., L.D.S.P., J.R.F., N.K.K., B.J.F., W.S., W.-P.K., S.O., S.H.P., A.B., A.M., S.R.N., L. Serebryannyy, M.C., R.S., M.I., I.P., S.P.H., A.J.M., A.E.L., J.G.G., K.C., P.M., E.S., J.A.S., S.V., S.T., E.E.C., J.R. Mascola, J.E.L., L.K.D., R.A.S.) and the Biostatistics Research Branch, Division of Clinical Research (Z.H.), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, the U.S. Public Health Service Commissioned Corps, Rockville (R.L.W., M.R.G.), and the Entomology Branch, Walter Reed Army Institute of Research, Silver Spring (A.C.C., J.R. Murphy) - all in Maryland; the Ragon Institute, Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA (A.H.I.); and the School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego (E.V.C.).