The antibody repertoire against gB is dominated by antibodies that do not neutralize virus and those which bind to unknown protein domains We intended to comprehensively analyze the human IgG anti-gB memory B-lymphocyte repertoire established by healthy HCMV infected individuals in terms of epitope specificity as well as neutralizing capacity. To this end we used the complete extraviral part of gB, as it is used in vaccination trials [24] , for sorting of IgG positive memory B-lymphocytes (CD19 + /CD27 + ) binding to fluorochrome-labeled gB by flow cytometry (Fig. S1A) . In a first set of experiments we analyzed the possibility to identify