Improved serodiagnosis of whooping cough caused by Bordetella pertussis by determination of IgG anti-LPF antibody levels.

The enzyme-linked immunosorbent assay (ELISA) has been used for the determination of the isotype and the specificity of Bordetella pertussis serum antibodies induced by natural infection and by vaccination. In a previous study (J. Med. Microbiol., 16, 417-426 (1984)) it was shown that the presence of pertussis serum IgA antibodies could be used as an indicator of infection: IgA antibodies were not induced by vaccination nor transported from the mother to the serum of the child. In the present study ELISA was used for the determination of IgA, IgM and IgG antibodies. From the results obtained with sera from suspected pertussis cases, it was concluded that antibodies against FHA are hardly induced by infection, in contrast to anti-LPF (determined in a fetuin sandwich ELISA) and anti-LPS antibodies. In view of the lower standard deviation of the mean anti-LPF antibody titer these antibodies were studied more extensively. From a number of bacteriologically proved pertussis cases, it was shown that high levels of IgG anti-LPF antibodies were found before IgA antibodies could be detected. On the other hand, we had the impression that IgG antibodies declined more rapidly than IgA antibodies. One has, however, to take into account that IgG antibodies are transferred from mother to child. From assay of sera from infants prior to, during and two months after vaccination (ages of vaccination: 3, 4, 5 and 12 months) it was concluded that IgG anti-LPF antibodies were induced to a much lower level by DTP-polio vaccination (10 O.U. per dose) than by natural infection.(ABSTRACT TRUNCATED AT 250 WORDS)