[1] NIAID, Div Aids, NIH, Bethesda, MD 20892 USA
[2] Scripps Inst, Dept Mol Biol, La Jolla, CA 92037 USA
[3] N Carolina State Univ, Coll Vet Med, Dept Microbiol Pathol & Parasitol, Raleigh, NC 27695 USA
[4] Colorado State Univ, Dept Pathol, Ft Collins, CO 80523 USA
[5] Univ Penn, Dept Hematol & Oncol, Philadelphia, PA 19104 USA
[6] Univ Penn, Sch Med, Dept Microbiol, Philadelphia, PA 19104 USA
[7] Univ Penn, Sch Med, Dept Med, Philadelphia, PA 19104 USA
[8] Ohio State Univ, Ctr Retrovirus Res, Columbus, OH 43210 USA
[9] Univ Glasgow, Dept Vet Pathol, Glasgow G61 1QH, Lanark, Scotland
[10] Univ Calif Davis, Sch Vet Med, Davis, CA 95694 USA
[11] Univ Florida, Coll Vet Med, Gainesville, FL 32610 USA
[12] NCI, Frederick Canc Res & Dev Ctr, Lab Genom Divers, Frederick, MD 21701 USA