Characterization of cells of the myeloid-monocytic lineage (ML-1, HL-60, THP-1, U-937) chronically infected with the human immunodeficiency virus-1.

The myeloid-monocytic cells ML-1, HL-60, THP-1 and U-937 were chronically infected (for more than 2 years) with the lymphotropic HIV-1 strain HTLV-IIIB. Reinfection experiments revealed that viruses obtained from chronically infected ML-1/HIV-1 and HL-60/HIV-1 cells show a low infectivity if tested with uninfected ML-1 and HL-60 cells in contrast to virus preparations from chronically infected THP-1/HIV-1 and U-937/HIV-1 with their corresponding uninfected cell lines. Analyses of selected cell surface markers showed a differential expression of CD4, CD8, CD11c, CD14, CD15, CD20, HLA-DR and HLA-DQ in non- or chronically infected cells. During chronical infection, the myeloid-monocytic cells lost their reactivity with peroxidase and esterase. In chronically infected cells, the steady-state levels for TNF-alpha mRNA remained unchanged while those for IL-6 decreased. The half-lives of transcripts of both TNF-alpha (t1/2: 70 min) and IL-6 (t1/2: 100 min) were nearly the same in uninfected and chronically infected HL-60 cells.