Vaccine-elicited Abs passively transferred to infants are capable of mediating low-level virus neutralization and ADCC. Infant plasma containing IgG Abs (A) against 1086.C, SHIV1157ipd3N4, linear (V3), and conformational V1V2 declined rapidly yet were initially able to mediate neutralization (B) versus tier 1 clade C virus MW965 and ADCC (C) against 1086.C and SHIV1157 gp120-coated target cells. Ab binding (D) to the surface of CEM.NKRCCR5 cells infected with either a 1086.C or an SHIV1157 infectious molecular clone was also observed at these early time points. In panel A, data points represent medians and error bars represent ranges. In panels B to D, lines represent individual infants.