ERVW-1 and viral infectious disease: It remains to be seen if the atypical dynamic profile of IgG3 responses to envelope glycoproteins elicited by CMV is antigen-intrinsic and might be recapitulated when these antigens are delivered by other means, or if it may represent an evasion strategy dependent on other viral genes or aspects of the innate response to viral infection in the context of this notoriously immunoevasive virus.