Human (top) and Old World monkey (OWM) (bottom) IgM (left) and IgG (middle) binding and complement-dependent cytotoxicity (CDC, at 25% serum concentration) (right) to wild-type (WT), GTKO, and TKO pig PBMCs. Results are expressed as mean ± SEM. (*p < 0.05, **p < 0.01; N.S. = not significant). On the y axis, the dotted line represents cut-off value of binding (relative GM: IgM 1.2, IgG 1.1), below which there is no binding. For CDC on the y axis, the dotted line represents cut-off value of cytotoxicity (6.4%), below which there is no cytotoxicity. (Note the difference in scale on the y axis between IgM and IgG.) (Reprinted with permission from Yamamoto T, et al. 202018).