Fig. (2) Molecular models of HERV-K10/IgG1Fc epitopes. Epitopes A and B taken from Westwood [18] and modeled using PyMOL (Molecular Graphics System, Version 1.2r3pre, Schrodinger, LLC: and enhanced using UCSF Chimera ( Molecular models were displayed in ‘mesh’ mode. Arrows point to amino acid residues highlighted and displayed on an IgGFc molecule (PDB file: 3AVE) using UCSF Chimera. CH: constant heavy 2 and 3 domains of IgG. In B: despite the amino acid substitution, there appears to be little change in molecular shape which may facilitate antibody cross-reactivity.