[1] INST ZOOL,MRC,AFRC,COMPARAT PHYSIOL GRP,LONDON NW1 4RY,ENGLAND
[2] MIDDLESEX HOSP,SCH MED,DEPT GENITOURINARY MED,LONDON W1P 7LD,ENGLAND
[3] UNIV LONDON UNIV COLL,SCH MED,FAC CLIN SCI,IMPERIAL CANC RES FUND,HUMAN TUMOUR IMMUNOL GRP,LONDON WC1E 6JJ,ENGLAND
[4] UNIV LONDON LONDON SCH HYG & TROP MED,DEPT MED MICROBIOL,LONDON WC1E 7HT,ENGLAND