[Experimental development of immunity to pertussis].

Experiments on animals inoculated intracerebrally with B. pertussis culture No 18-323, serovar 1.2.3, revealed that among sera against B. pertussis strains of different serovars sera against the strains of serovar 1 showed the highest protective potency, and sera against the strains of serovar 1.2 showed the lowest protective potency. In active immunization experiments vaccines from the strains of serovar 1 proved to be least effective, while the immunogenic properties of vaccines from the strains of serovar 1.2 were found to be most pronounced. Since this discrepancy in the above results is due to the fact that the strains of serovar 1 in small doses were unable to create a stable focus of antigenic stimulation, it is not expedient to include strains belonging to serovars other than 1.2 into vaccinal preparations.