Maternal immunization and the immune response of neonates to pneumococcal polysaccharides.

The effect of maternal immunization on the immune response of neonates to pneumococcal polysaccharides and the characterization of IgG receptor molecules have been reviewed and studied. Maternal immunization with pneumococcal 19F polysaccharide during gestation and/or lactation induces a significantly stronger response in offspring. When young mice born to pregnant mice immunized with a polysaccharide-protein conjugate (e.g., 19F polysaccharide-human IgG) are given an additional dose of polysaccharide-protein conjugate immunogen, they develop an antibody response stronger than that of young mice not receiving additional immunogen. Injection of female mice (before their mating) with type 19F or type 3 polysaccharide may also induce a stronger antibody response in offspring. Combined passive immunization with immunoglobulin and active immunization do not cause suppression or observable harmful immunologic effects; rather, such immunization may elicit sufficient 19F antibody formation for protection against infection during early life. IgG receptor molecules have been isolated from rabbit yolk-sac membranes, and their physicochemical properties have been characterized.