FIG. 6.

Neutralizing antibodies in hMPV-infected mice. Mice were infected with hMPV (10⁷ TCID₅₀s)and sacrificed weekly to determine antibody titers by a plaque reduction neutralization assay. The lower detection limit for this assay is 2 log₂ serum dilution. At 6 weeks postinfection, mice were reinfected with hMPV, and neutralizing antibody titers were determined 1 week later. The dashed line represents titers in the sera of reinfected mice. Data are means for four to six mice per group and are representative of two experiments.