[1] Biomed Primate Res Ctr, Dept Virol, NL-2288 GJ Rijswijk, Netherlands
[2] Edward Jenner Inst, Newbury RG20 7NN, Berks, England
[3] John Radcliffe Hosp, Inst Mol Med, Oxford OX3 9DS, England
[4] NCI, Dept Expt Immunol Branch, NIH, Bethesda, MD 20817 USA
[5] Harvard Univ, Dept Mol & Cellular Biol, Cambridge, MA 02138 USA
[6] Karolinska Inst, Dept Virol, S-10521 Stockholm, Sweden
[7] Univ London Imperial Coll Sci Technol & Med, Jefferis Trust Labs, Dept Genitourinary Med & Communicable Dis, London W2 1NY, England
[8] Univ London Imperial Coll Sci Technol & Med, Chelsea & Westminster Hosp, Dept Immunol, London SW10 9NH, England