[1] Univ London Imperial Coll Sci Technol & Med, Sch Med, Dept Immunol, London W2 1PG, England
[2] Univ London Imperial Coll Sci Technol & Med, Sch Med, Dept Genitourinary Med & Communicable dis, London W2 1PG, England
[3] Kagoshima Univ, Fac Med, Dept Med Informat, Kagoshima 8908520, Japan
[4] Kagoshima Univ, Fac Med, Dept Internal Med 3, Kagoshima 8908520, Japan
[5] Kagoshima Univ, Fac Med, Ctr Chron Viral Dis, Div Mol Pathol, Kagoshima 8908520, Japan
[6] Churchill Hosp, Nuffield Dept Surg, Oxford Transplant Ctr, Oxford OX3 7LJ, England
[7] John Radcliffe Hosp, Inst Mol Med, Oxford OX3 9DU, England
[8] Univ Oxford, Dept Zool, Oxford OX1 3PS, England