Molecular cloning of two west African human immunodeficiency virus type 2 isolates that replicate well in macrophages: a Gambian isolate, from a patient with neurologic acquired immunodeficiency syndrome, and a highly divergent Ghanian isolate.

Human immunodeficiency virus type 2 (HIV-2)-related viruses were isolated from a Gambian dying of exclusively neurological disease (HIV-2D194) and from an asymptomatic Ghanian (HIV-2D205). Both strains exhibited properties of HIV-1 biological subtype c: they grew slowly and induced few or no syncytia but eventually produced high levels of particle-associated reverse transcriptase in cultures of fresh peripheral blood lymphocytes, and they established stable infection of T-lymphoma (HUT-78) and monocytic (U937) cell lines. Each produced even higher levels of reverse transcriptase when fresh human monocytes/macrophages were used as target cells. The viruses were molecularly cloned after a single passage in culture, in order to minimize in vitro selection of subtypes present in vivo. Restriction-site analysis showed heterogeneity within each isolate. Nucleotide sequence analysis of a portion of the HIV-2D194 genome revealed that it is a member of the prototypic HIV-2 family, displaying 13% divergence versus HIV-2ROD and HIV-2NIHZ, as compared to 9% divergence between HIV-2ROD and HIV-2NIHZ. In contrast, HIV-2D205 is the most highly divergent HIV-2 strain yet described: it is equidistant in relation between the known HIV-2 strains and the simian immunodeficiency virus isolates from rhesus macaque monkeys (23-25% divergence).