FIG. 5.

Replication of chimeric viruses in primary MDMs and PBMC. MDMs were prepared by differentiating freshly elutriated monocytes on Sterilin plates (Bibby Sterilin, Stone, Staffordshire, United Kingdom) over a 14-day period in macrophage medium (Dulbecco modified Eagle medium [DMEM], 10% pooled normal human serum, 1 mM sodium pyruvate, 2 mM glutamine, 25 U of penicillin/ml, and 25 μg of streptomycin/ml) as previously described (21). Differentiated MDMs were frozen in DMEM containing 20% human serum and 7.5% dimethyl sulfoxide. Cells were thawed and seeded 1 day prior to infection in 96-well plates (Nunc) (10⁵ cells in 200 μl per well). MDMs (a through c) or PBMC (d) were infected with the parental virus or one of the chimeric viruses. Infection, sample collection, and analysis of progeny virus production were carried out as described for Fig. 4.