The lack of IgG3 response and greater IgG2b response to the OMV vaccine in the present study was also seen for the vaccine VA-MENGOC-BC in mice, with IgG2b antibody titres correlating with SBA activity.47 Although lower in quantity, IgG2b antibodies were detected in response to vaccination with Ad-P1.7,16, so the subclass of IgG antibodies alone cannot account for the lack of bactericidal activity in response to this vaccine. This evidence concerns the gene IGHG3 and breast cancer.