Enhancement of vaccine-specific cellular immunity in infants by passively acquired maternal antibody.

The known protective effects of passively acquired maternal antibody on the resistance of newborns to infections have prompted widespread interest in maternal vaccination. However, a range of animal model and human studies indicate potential inhibitory effects of maternal antibody on vaccine-specific humoral responses in infants. In the present study we have examined the relationship between maternally acquired TT-specific IgG present before DTaP vaccination and subsequent TT-specific T-cell memory responses at 12 and 18 months, in a cohort of 118 infants. We demonstrate a strong positive association between TT-specific cellular immunity as evidenced by increased IL-4, IL-5 and IL-13 responses, and maternal TT-specific IgG.