Abstract
Examination of 50 paired maternal and cord sera for O antibodies against various Enterobacteriaceae showed that agglutinins could not be demonstrated in the cord sera. The hemagglutination test revealed the presence of antibodies in 6-78% of the cord sera depending upon the antigen used. The antiglobulin hemagglutination test detected incomplete antibodies in an additional 14-46% of the cord sera. The antiglobulin hemagglutination test enhanced the hemagglutinin titers of cord sera to a greater extent than those of maternal sera. With one exception the maternal antibody titers were higher than those of the corresponding cord sera. The specificity of the antiglobulin hemagglutination test was demonstrated by means of absorption experiments. The placental transfer of enterobacterial antibodies from mother to fetus is discussed with particular reference to incomplete antibodies.