ACQUISITION OF HOST CELL-SURFACE-DERIVED MOLECULES BY HIV-1

Objective: To determine the acquisition of host cell-membrane-derived molecules by HIV-1 during the budding process, and to investigate whet her the uptake of these molecules is cell-type-specific and selective. Design: Virions, propagated by four different cell types were analyse d for the presence of adhesion molecules, glycosylphosphatidylinositol (GPI)-anchored proteins and various cell-surface markers. The pattern was compared with the phenotype of the HIV-1-infected cell. Methods: For phenotypic analysis of virions a two-step assay was used. In the f irst step, virus was captured with monoclonal antibodies (in some case s polyclonal sera) against different cell-membrane proteins. In a seco nd step, the presence of virus was measured by determining the concent ration of the virus-specific p24 core antigen. The expression of surfa ce molecules on uninfected and HIV-1(IIIB)-infected cells was analysed by FACS. Results: Depending on the cell type used for virus propagati on, different cell-membrane molecules were found on the virus surface reflecting the corresponding cell type. The uptake of these molecules was selective to a certain degree. No CD4 and CD87 molecules were dete ctable on HIV-1, although both molecules were present on uninfected an d HIV-1-infected cells. CR3 and CDw108 could not be seen on uninfected cells, but were detectable on infected cells and virions.Conclusions: During the budding process HIV-1 acquires a variety of cell-type-spec ific cell-surface molecules. Certain cell-membrane molecules become up regulated during HIV-1-infection and are then found on virions, wherea s other molecules remain on the cell surface and do not become incorpo rated.