Neutralizing antibodies to gB based CMV vaccine requires full length antigen but reduced virus neutralization on non-fibroblast cells limits vaccine efficacy in the guinea pig model.

•Only full length GPCMV gB can form triplex complex.•Full length gB elicits better neutralizing antibodies than truncated protein.•Anti-gB can neutralize fibroblast infection and cell fusion entry pathway.•Anti-gB is less effective on cells that also require viral pentamer for cell entry.•A gB vaccine reduces but does not prevent virus dissemination in the animal model.