PROTECTION OF GROUP B STREPTOCOCCUS TYPE-SPECIFIC ANTIBODY TO NEWBORN MICE WITH LETHAL GBS INFECTION

Li L1, Ye HM1, Yang YH2, Shen XZH2, Shen AD2, Huang DM1

1 The Third Hospital, Beijing University, Beijing, China

2 Beijing Children’s Hospital, Beijing, China

 

Objective: To investigate the protection of group B streptococcus (GBS) type-specific antibody to newborn mice with lethal GBS infection.

Methods: Active immunize the pregnant mice by injecting intra-peritoneally using GBS type III polysaccharide-tetanus toxoid conjugate vaccine, measure the type-specific antibody of the mother mice due to the immune response and the level of this antibody in the newborn mice with ELISA. Then induce newborn mice lethal infection with the same type of GBS, investigate the death rate. The group in which the pregnant mice were injected with normal saline and the newborn mice were challenged with lethal dose of GBS served as the group of infection control, while the group without any procedure served as normal control.

Results: The amount of type-specific antibody in the pregnant mice increased greatly after immunization. The geometric mean of the level of the antibody was increased from 0.039μg/ml before immunization to 0.728μg/ml after immunization(P<0.001). The level of this kind of antibody in newborn mice was higher than infection control, which is 0.538μg/ml, 0.043μg/ml respectively P<0.001,the newborn mice death rate which is 36.92% after lethal infection was lower than infection control which is 97.01%(P<0.001).

Conclusion: The GBS type III conjugate vaccine can induce the type-specific antibody in pregnant mice which transferred to the newborn mice and protect them from lethal infection of GBS type III, and humoral immune plays an important role in the anti-infection of GBS.

 
0576