Since Env- and V1V2-specific IgG3 was associated with lower infection risk in the RV144 trial [7] and was shown to decline soon after vaccination [7,14], we examined whether ALVAC and/or AIDSVAX B/E late boosting improved the level and breadth of IgG3 binding antibodies against HIV-1 gp120, gp140, and V1V2 envelope protein sequences. The gene discussed is IGHG3; the disease is infection.