[1] NIAID, Mol Microbiol Lab, Mol Virol Sect, NIH, Bethesda, MD 20892 USA
[2] NIAID, Infect Dis Pathogenesis Sect, Comparat Med Branch, Div Intramural Res,NIH, Bethesda, MD 20892 USA
[3] Mem Sloan Kettering Canc Ctr, Canc Biol & Genet Program, New York, NY 10021 USA