Pertussis whole cell vaccine: relation between intracerebral protection in mice and antibody response to pertussis toxin, filamentous hemagglutinin and adenylate cyclase

Abstract

N:NIH mice were vaccinated according to the WHO recommendations for the potency test with the Second International Standard for Pertussis Vaccine (ISPV). Blood for serological investigation was taken from the animals on day 14 post immunization before intracerebral challenge with Bordetella pertussis 18323 was done. The relationship between anti-pertussis toxin, anti-filamentous hemagglutinin and anti-adenylate cyclase antibody levels as measured by ELISA and protection from intracerebral challenge was studied. The proportion of surviving mice increased in correlation with increasing anti-PT titres; a protective level of 4 ELISA units/ml was found. Such relationship between protection against intracerebral challenge and antibody titres was not found for anti-FHA nor for anti-AC antibodies, thus suggesting that these antibodies do not play an important role in protection in this model. The excellent correlation between anti-PT antibody titres and protection suggests that the measure of anti-PT response could be a useful tool for estimating the potency of whole-cell vaccines. The development of an alternative method for testing the potency of pertussis whole-cell vaccines based on the anti-PT response should be considered.