FIG 2 .

5C4 monoclonal antibody (mAb) binds to noroviruses. (A) Neighbor-joining phylogenetic tree of 10 murine norovirus (MNV) strains using the 541-amino-acid capsid protein. (B and C) Plates were coated with MNV strains (B) or human norovirus (HuNoV) VLPs (C) and tested for reactivity to 1 μg per well of MAb 5C4. MNV1 and mock lysate were used as positive and negative controls, respectively. The dashed line represents twice the absorbance values at 415 nm (A₄₁₅) for the negative control and indicates the threshold for a positive signal. OD, optical density. (D) MNV strains were incubated with the indicated concentrations of MAb 5C4 for 30 min at 37°C before a plaque neutralization assay was performed. Virus titers were determined after 48 h of incubation and are shown relative to the absence of antibody. Data are presented as means ± standard errors of the means (SEM) of the results from at least three independent experiments.