[1] UNIV ALABAMA, DEPT MED, BIRMINGHAM, AL 35294 USA
[2] UNIV ALABAMA, DEPT MICROBIOL, BIRMINGHAM, AL 35294 USA
[3] UNIV NOTTINGHAM, QUEENS MED CTR, DEPT GENET, NOTTINGHAM NG7 2UH, ENGLAND
[4] WALTER REED ARMY INST RES, HENRY M JACKSON FDN RES LAB, ROCKVILLE, MD 20850 USA
[5] NIAID, VACCINE RES & DEV BRANCH, BETHESDA, MD 20892 USA
[6] WHO, WHO NETWORK HIV ISOLAT & CHARACT, GLOBAL PROGRAMME AIDS, CH-1211 GENEVA, SWITZERLAND
[7] GEORG SPEYER HAUS CHEMOTHERAPEUT FORSCHUNGSINST, FRANKFURT, GERMANY
[8] NATL INST BIOL STAND & CONTROLS, LONDON NW3 6RB, ENGLAND
[9] NIAID, DIV AIDS, BETHESDA, MD 20892 USA
[10] WALTER REED ARMY INST RES, HENRY M JACKSON FDN RES LAB, ROCKVILLE, MD USA
[11] INST SALUD CARLOS 3, CTR NACL BIOL CELULAR & RETROVIRUS, MADRID, SPAIN
[12] STANFORD UNIV, SCH MED, DEPT MICROBIOL & IMMUNOL, STANFORD, CA 94305 USA
[13] UNIV AMSTERDAM, HUMAN RETROVIRUS LAB, AMSTERDAM, NETHERLANDS
[14] UNIV ALABAMA, DEPT MED, BIRMINGHAM, AL 35294 USA
[15] INST COCHIN GENET MOLEC, F-75014 PARIS, FRANCE
[16] CTR DIS CONTROL & PREVENT, ATLANTA, GA 30341 USA
[17] ST MARYS HOSP, SCH MED, LONDON, ENGLAND
[18] NCI, VIRUS BIOL UNIT, FREDERICK, MD 21701 USA
[19] KAROLINSKA INST, STOCKHOLM, SWEDEN
[20] SWEDISH INST INFECT DIS CONTROL, STOCKHOLM, SWEDEN
[21] LOS ALAMOS NATL LAB, LOS ALAMOS, NM USA