Regulation of pertussis toxin and lipopolysaccharide levels of Bordetella pertussis 134 in response to modulators

  Whooping cough (pertussis) is a highly contagious disease of the human respiratory tract, which is caused by Bordetella pertussis. Reemerge of pertussis in some highly immunized populations and divergency in gene order among several B. pertussis strains promoted this research to study the change of pertussis toxin (PT) and lipopolysacharide levels in response to the different environments. This study conducted an extensive investigation of antigenic modulation of B. pertussis strain 134 in the presence of different chemicals. One of the findings of this research, for the first time, was that barium ion has growth inhibitory role on B. pertussis 134, when added in high concentration to CBA plates. Nicotinic acid, magnesium sulfate, and magnesium chloride have shown the significant modulating effect on the basis of reduction of PT levels. Our data demonstrated quantitatively that the modulation of B. pertussis yields high levels of LPS. Our results have showed the strong modulatory effects of FeCl3 on reduction of PT levels. In general, this study provided collective data which are strongly applicable to explain modulation of B. pertussis, and also introduces new modulators which promote more study on gene order of B. pertussis.