Characterization of human T-cell lines harboring defective human immunodeficiency virus type 1

Defective HIV-producing T-cell lines were subcloned from MT-4/HIVHTLV-IIIB' MOLT-4/HIVHTLV-IIIB, and H9/HIVHTLV-IIIB cell lines chronically infected with HIV. The NY-M10 cell line derived from MOLT-4/HIVHTLV-IIIB and the NY-H6 cell line derived from H9/HIVHTLV-IIIB produce defective HIV, which lacks the ability to infect human T-cell lines. NY-M10 cells retain the capacity to form multinucleated giant cells in cocultivation with HIV-uninfected CD4-positive cells. However, NY-H6 cells failed to fuse with CD4-positive cells. Electron microscopic analysis indicated that the defective HIV produced from NY-M10, like those reported previously, lacked the structure of the nucleocapsid, and the virion released from NY-H6 was indistinguishable from those of authentic HIV particles. Southern and Northern blotting analyses of NY-M10 and NY-H6 cleared that the genome of those defective viruses was not significantly deleted, suggesting minor mutation(s) should take place on the viral genome.