The N-linked carbohydrate attachment site of human IgG1 Ab has been eliminated by site-directed mutagenesis. Effector functions of aglycosylated Ab was then compared to its native counterpart. Aglycosylated Ab failed to exhibit any ADCC activity, but a significant level of CDC activity was retained by the aglycosylated Ab. These observations differ from those reported previously. Serum half-life and biodistribution of aglycosylated Ab in mice were comparable to the native Ab. Together, these results show that some, but not all, effector functions of a human IgG1 Ab are affected by aglycosylation.