Figure 4

The antigenic 3D cartography for 3 vaccine strains, the attenuated YX10-D90 strain, and 14 field isolated IBV strains. Viruses of the same genotypes are labelled with same tag. One unit in the 3D map corresponds to a two-fold change in the cross-neutralization assay. Distances between two viruses greater than two units on the 3D antigenic cartography map were considered different serotype strains.