Quantification of bovine IgG, IgM and IgA antibodies to Clostridium perfringens B-toxin by enzyme immunoassay II Systemic effects of maternally derived antibodies on immunization of newborn calves.

A quantitative competitive binding "triple sandwich" enzyme immunoassay was used to evaluate pathogen/class-specific antibody responses in forty-eight Holstein-Friesian calves vaccinated against Clostridium perfringens B-toxin at various ages postpartum. To assure a wide serum pathogen/class-specific immunoglobulin concentration range, one-half of all calves were from previously vaccinated dams. Calves initially vaccinated at three days produced both a primary and secondary pathogen-specific antibody response, whereas calves initially vaccinated at twelve and twenty-one days produced only secondary responses. Maternally-derived antibodies were found to suppress neonatal antibody production following primary immunization. They were also found to influence secondary humoral immune responses, although in a diminished capacity. Class-specific immunoglobulin levels did not affect pathogen-specific antibody production. Pathogen-specific antibodies were theorized to negatively "feedback" upon their own production whereas total class-specific levels are believed to affect accessory cell populations. Neonatal immunization in the presence of maternal antibody was demonstrated efficacious with respect to production of primary and secondary antibody responses. Based upon the results from this experiment, it is recommended that calves be vaccinated at three days postpartum with a secondary booster administered not later than sixty-three days.