Figure 1.

Synthesis of α-gal epitopes (A) and N-glycolyl-neuraminic acid (Neu5Gc) (B) on glycans of enveloped virus glycoproteins. The “capping” of the glycans occurs in the trans-Golgi compartment of host-cells and is mediated by α1,3galactosyltransferase and α2,3 and α2,6 sialyltransferases, using UDP-Gal and CMP-Neu5Gc as high-energy sugar donors, respectively. The hydroxyl of Neu5Gc differentiating it from Neu5Ac is indicated. Viral glycoproteins are assembled on cell membranes to form the virus envelope, followed by budding of the virus. Antibodies binding to these glycans and the species producing them are indicated. Modified from ref. [16].