DETECTION OF VIRAL SURFACE-ANTIGENS ON HIV-2BEN INFECTED HUMAN TUMOR-CELL LINES BY FLOW-CYTOMETRY

The human monocytic cell line U-937 clone 2 and two T-cell lines CEM a nd MOLT-4 clone 8 were infected with HIV-2ben, a recent isolate of HIV -2. Infection and subsequent antigen expression on the cell surface wa s monitored by flow cytometry using a rabbit-anti-serum against tween- ether-treated HIV-2ben and a fluoresceinisothiocyanate-conjugated IgG against rabbit-IgG. The sensitivity of the three cell lines to infecti on with HIV-2ben correlated with the percentages of CD4-expressing cel ls but not with the levels of CD4-expression on the cell. The appearan ce of viral surface antigens preceeded the formation of syncytia and c orrelated closely with the infecting virus dose. After 1-2 weeks in cu lture, 20-85% of the cells of each line expressed viral surface antige ns. The variation depended on the cell type and cell culture condition s. The MOLT-4 clone 8 and the U-937 clone 2 cells died around 10 or 20 days, respectively, after HIV-2ben infection. Only HIV-2ben infected CEM cells grew permanently. Flow cytometry was an appropriate method t o monitor the expression of viral proteins on the cell surface of HIV- infected cell lines. Flow cytometry proved to be more sensitive than d etermination of RT activity in supernatants of HIV-infected cells and more precise than light microscopy examinations.