Antigenic Diversity of Human Norovirus Capsid Proteins Based on the Cross-Reactivities of Their Antisera

Figure 1. Phylogenetic analysis of the nucleotide sequences of the P domain of 23 human norovirus (HuNoV) genotypes by Maximum Likelihood, with 1000 bootstrap replicates. Bootstrap values are shown next to the branches. The scale bar represents the genetic distance of the nucleotide substitutions per site.

Figure 2. Standard curve of GI norovirus antisera dilution and OD450 value determined by enzyme-linked immunosorbent assay.

Figure 3. Standard curve of GII norovirus antisera dilution and OD450 value determined by enzyme-linked immunosorbent assay.

Figure 4. Cross-reactivities of GI HuNoV antisera by titer ratios.

Figure 5. Cross-reactivities of GII HuNoV antisera by titer ratios.

Figure 6. Alignment of P domain amino acid (aa) sequences within antigenic epitopes of 23 human norovirus (HuNoV) strains. Yellow, antigenic site; *, fully conserved aas; black boxes, conserved antigenic regions. Red, blue, orange, green, purple, and grey arrows indicated epitope A, B, C, D, E, and F, respectively. Blue letters represented the conserved amino acids of GI genogroup or GI and GII genogroups, green letters represented conserved amino acids only in the GII genogroup, black letters represented non-conserved amino acids.