TABLE 1.

Sera from vaccinated mice show potency in preventing infection of myeloid cells in vitro^a

Vaccine	Cell line neutralization readoutb
	RAW 264.7 macrophage	NIH 3T3 fibroblast	NMuMG (epithelial)	SVEC4-10 (endothelial)
WT-MCMV	1:1,428–1:3,333	1:400–1:2,000	1:111–1:167	1:20–1:100
ΔM33-MCMV	1:333–1:1,000	1:14–1:25	1:9–1:14	<1:10

^aHalf-log dilutions of sera taken from mice vaccinated or not with either WT-MCMV or ΔM33 MCMV were mixed with MCMV-GFP for 90 min at 37°C. Antibody-virus mixtures (in triplicate) were added to monolayers of either RAW macrophages, NIH 3T3 fibroblasts, NMuMG epithelial cells, or SVEC4-10 endothelial cells. After 20 h, the proportions of GFP⁺ cells in each culture were quantified by flow cytometry. The percentages of cells infected in the absence of sera were equivalent across all cell lines. Pooled sera from unvaccinated (i.e., naive) animals failed to exhibit 50% neutralization on any cell line, even at the highest concentration (10% [vol/vol]) used.

^bValues are expressed as the serum dilutions required to neutralize 50% of the virus inoculum.