CD4 and cancer: In co-culture of these cells (RKO OKT3) with human PBMCs, we found that GB265, GB266, and GB266T with wildtype IgG1 Fc outperformed parental antibodies in the promotion of cancer cell killing (Fig. 3a), CD8 T cell expansion (Fig. 3b), and CD4 T cell expansion (Fig. 3c).