The influence of maternal immunization on light chain response to Haemophilus influenzae type b vaccine

The repertoire of human antibodies to Haemophilus influenzae type b polysaccharide (Hib PS) has been extensively characterized. In response to Hib PS vaccines, both IgG1 and IgG2 antibodies are produced. Based on the Vkappa gene used for the antibodies, heamophilus antibodies can be divided into A2 and non-A2 antibodies. A2 antibodies account for the majority of heamophilus antibodies, are generally more functional, and are specific for heamophilus polysaccharide. In contrast, non-A2 antibodies cross-react with Escherichia coli K100. Studies of placental transfer showed that IgG1 antibodies cross the placenta better than IgG2 antibodies and the A2 antibodies better than non-A2 antibodies. Babies born to mothers who were immunized with a heamophilus vaccine had a high level of antibodies to Hib PS but the antibody level decreased during the first 6 months. The children also responded to a heamophilus conjugate vaccine.