HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1)-SERONEGATIVE INJECTION-DRUG USERS AT RISK FOR HIV EXPOSURE HAVE ANTIBODIES TO HLA CLASS-I ANTIGENS AND T-CELLS SPECIFIC FOR HIV ENVELOPE

The question of whether persistently seronegative persons at high risk for human immunodeficiency virus type 1 (HIV-1) infection exhibit HIV -1-specific T cell responses and antibodies to HIV-1 envelope epitopes shared with selected HLAs was assessed, These antibodies are not dete ctable by conventional serologic methods, Envelope-specific helper T ( Env-Th) cell responses and antibodies specific for the HIV/HLA epitope s were studied in 21 HIV-1-negative injection drug users (IDUs), HIV/H LA antibodies were detected in 7 (33.3%) of 21 IDUs and 4 (4.3%) of 94 low-risk controls, Env-Th cell responses were detected in 16 (76.2%) of 21 IDUs and in 2 (3.1%) of 65 low-risk controls, All HIV/HLA antibo dy-positive IDUs also had Env-Th cell responses, These findings confir m the presence of HIV-1-specific immunity in conventionally seronegati ve individuals, Further characterization of these responses could prov ide the basis for new preventive strategies.