Transplacental transfer of antibodies to some respiratory viruses.

A group of 200 paired mother-newborn sera (umbilical sera) were used for the determination, by hemagglutination inhibition test of antibody levels for parainfluenza virus types 1, 2 and 3 and, by ELISA test of class IgG antibodies for Respiratory Syncytial Virus (RSV). In 54 paired sera the RSV antibodies also were determined in IgG subclasses and in 4 paired sera RSV protein antibodies were determined by Western-Blot in IgG class and IgG subclasses. Parainfluenza virus antibodies were found to occur in higher titres in the newborn than in the mother sera. On the other hand, IgG class antibodies for RSV were shown in more mothers than in their newborns. In the IgG-1 subclass RSV antibodies were more frequent among newborns than in their mothers, the reverse situation was observed in the IgG-2 and IgG-3 subclasses. In the IgG-4 subclass per cent of mothers and newborns who had antibodies was equal. In the Western-Blot assay, most bands corresponding to antibodies for RSV proteins were detected in the IgG class of mother sera, and in the IgG-1 subclass in newborn sera. Rather distinct transfer of antibodies for protein G was found in the IgG class, and a little lower--in the IgG-1 and IgG-3 subclasses.