Detection of human immunodeficiency virus (HIV) in cultures of lymphocytes from HIV-seropositive persons with special reference to an enzyme immunoassay.

Three different assay systems for monitoring the production of human immunodeficiency virus (HIV) in infected cells were compared. These were (1) a reverse transcriptase assay (RTA), (2) an indirect immunofluorescence assay (IFA), and (3) an enzyme immunoassay (EIA) for detecting HIV antigen in vitro. MOLT-4 subclone 1 cells were infected with serial dilutions of the HTLV-IIIB strain of HIV. Six days after infection, production of HIV was examined by the three methods. EIA was most sensitive showing 64-fold higher sensitivity than RTA, which in turn was fourfold more sensitive than IFA. We applied EIA for detecting HIV in the lymphocyte cultures derived from 18 HIV-seropositive persons. By means of the three systems HIV was isolated from lymphocyte cultures derived from one of nine (11%) asymptomatic persons and from five of nine (56%) symptomatic patients. Interestingly, it was noticed that four samples of lymphocytes did not allow the isolation of HIV but gave positive results by EIA only. Thus, the detection rate of HIV was increased by the application of EIA, to three of nine (33%) persons in the asymptomatic group and to seven of nine (78%) patients in the symptomatic group. Possible use of this assay system for following the development of acquired immunodeficiency syndrome is discussed.