THE ORIGIN OF HIV-1 ISOLATE HTLV-IIIB

THE striking similarity between the first two human immunodeficiency v irus type 1 (HIV-1) isolates Lai/LAV (formerly LAV, isolated at the Pa steur Institute1,2) and Lai/IIIB (formerly HTLV-IIIB, reported to be i solated from a pooled culture at the Laboratory of Tumor Cell Biology (LTCB) of the National Cancer Institute3,4) provoked considerable cont roversy in light of the high level of variability found among subseque nt HIV-1 isolates5. In November 1990, the Office of Scientific Integri ty at the National Institutes of Health commissioned our group to anal yse archival samples established at the Pasteur Institute and LTCB bet ween 1983 and 1985. Retrospective analyses6,7 have shown that contamin ation of a culture derived from patient BRU by one from patient LAI wa s responsible for the provenance of HIV-1 Lai/LAV; the contaminated cu lture (M2T-/B) was sent to LTCB in September 1983(6,7). Our goals were to determine which HIV-1 variants were present in the samples and the sequence diversity among HIV-1 isolates from the earliest stages of t he AIDS epidemic. We examined archival specimens and report here the d etection of six novel HIV-1 sequences in the cultures used to establis h the pool: none is closely related to HIV-1 Lai/IIIB. A sample derive d from patient LAI contained variants of both HIV-1 Lai/IIIB and HIV-1 Lai/LAV, and a sequence identical to a variant of HIV-1 Lai/IIIB was detected in the contaminated M2T-/B culture. We conclude that the pool , and probably another LTCB culture, MoV, were contaminated between Oc tober 1983 and early 1984 by variants of HIV-1 Lai from the M2T-/B cul ture. Therefore, the origin of the HIV-1 Lai/IIIB isolate also was pat ient LAI.