Figure 3. Within-host competition in B6 mice is dependent on NK cells.

To assess the role of NK cell on within-host competition, NK cells were depleted from B6 mice by i.p. injection of 150 µg of the monoclonal antibody PK136 at day −1, 0 and then every 5 days until day 15 p.i. On day 0 mice were inoculated i.p. with 1×10⁴ pfu of either a single MCMV strain (closed symbols) or a total of 1×10⁴ pfu of a mixed inoculum of equal proportions of C4A and C4C (half filled diamonds - plaque assay or open symbols – strain specific PCR). A. Titers of infectious virus were determined by plaque assay in salivary glands of non-manipulated mice infected with either C4A or C4C (closed symbols), or in PK136 (anti-NK1.1) or PBS treated mice co-infected with C4A and C4C (half filled diamonds). B. Viral DNA levels in B6 mice treated with PK136 (anti-NK1.1) and co-infected with C4A and C4C. Note both C4A and C4C DNA were detectable following NK cell depletion. C. Viral DNA levels in B6 mice treated with vehicle (PBS) and co-infected with C4A and C4C. Note competition was retained, with C4A DNA undetectable in the salivary glands. The x-axis represents the limit of detection for plaque assays (100 pfu/g of tissue) and the multiplex qPCR (1×10⁴ copy number/g of tissue), n = 5 mice per group.