Studies On Protective And Inhibitory Effects Of Maternal Antibodies Induced By Influenza DNA Vaccine

Neonatal animals were not considered as suitable vaccine recipients either because of immune immaturity or because passively delivered antibody interferes with immune induction. Maternal immunization is the major form of protection against many infectious diseases in early life. In this paper, transmission of vaccine-specific maternal antibodies and protection of offspring against a lethal influenza virus challenge were studied. Adult female BALB/c mice were immunized i.m. with plasmids DNA encoding influenza virus hemagglutinin (HA), neuraminidase (NA) or mixtures of the two plasmid DNAs (HA+NA). The levels of specific antibodies in sera of offspring at different ages and the survival rates following the lethal viral challenge were valued. Effective transmission of maternal antibodies was observed, and maternal antibodies in offspring could last for several weeks. Along with the growth of offspring, their antibody titers in vivo decreased and their ability against virus infection decreased accordingly. The HA-specific maternal antibodies protected the offspring from a lethal influenza infection till 2 weeks old, and the NA-specific maternal antibodies protected offspring till 4 weeks old. Furthermore, antibodies transferred by mother immunized with the mixture of HA DNA and NA DNA could protect 6-week old offspring from the lethal viral...