Maintenance of glycoprotein-determined phenotype in an HIV type 1 (pNL43) env gene-cassetting system.

Here we report the construction and use of a full-length env gene-cassetting system, C2, based on the HIV-1 infectious molecular clone NL43. C2 produces virus with the same phenotype as NL43 but with 2-fold lower growth kinetics. The latter probably relates to alteration in the vpu and/or nef genes. C2-env chimeras of macrophage-tropic and T cell-tropic laboratory strains and primary HIV-1 isolates retain the glycoprotein-determined phenotypes of their parent viruses. The cassette will assist studies of HIV-1 pathogenesis.