Although
vaccines against Bordetella pertussis, the causative agent of
whooping cough, have been in use for over 50 y, the disease has remained endemic and is still a public health problem in many countries. It has been shown that antibody titres against
pertactin, which is 1 of the exposed
virulence factors of
pertussis, correlate with protection and
pertactin is now 1 of the components of most acellular
pertussis vaccines. However, little is known about the structure and location of protective
epitopes on
pertactin. Here we set out to investigate the antibody response using naturally occurring
pertactin variants and deletion derivates. We found the N-terminus of
pertactin to be immunodominant in both rabbits and humans. In contrast to vaccinated rabbits, we could not detect
pertactin type-specific
antibodies in human sera. In conclusion, these results show for the first time to which defined regions of the
pertactin molecule antibody responses are induced. It also suggests that the amount of
pertactin type-specific
antibodies will not be very large and that the variation in
pertactin probably will not constitute a problem in highly immune individuals.