Figure 4From: Differences in the tissue tropism to chicken oviduct epithelial cells between avian coronavirus IBV strains QX and B1648 are not related to the sialic acid binding properties of their spike proteinsSchematic drawing of a soluble S1 protein construct. It consists of the S1-unit (aminoacids 1–536 of the spike proteins) of IBV QX- or B1648 spike protein fused to a human IgG-Fc tag.Back to article page