Fig 5.

Multistep growth analysis of M33 MCMV recombinants (A) and US28 recombinants (B) in primary BMM cultures from adult C57BL/6 mice. BMM were harvested from femurs and tibias of mice and cultured in the presence of human recombinant colony-stimulating factor 1 (CSF-1; 10⁴ U/ml; a kind gift from M. Sweet, University of Queensland) for 5 to 9 days. BMM were infected at an MOI of 10 (relative to MEF; corresponds to an MOI of approximately 0.1 for BMM); supernatants were taken at the indicated times and assayed for infectious virus by plaque assay on MEF. (A) wt M33 (●), M33R131Q (○), M33ΔC38 (♢), and M33-null mutants (lacZ insertion [▲] and M33 premature stop [△]); (B) wt US28 (●), US28ΔC54 (♢), US28R129Q (○), US28RQ/ΔC54 (□) and M33-null mutants (lacZ insertion [▲] and M33 premature stop [△]). Data are mean titers (log₁₀ PFU/ml) ± SD from two experiments performed in triplicate. The origin of the y axis is adjusted to reflect the lower limit of virus detection.