The serotypes of Bordetella pertussis isolated in Great Britain between 1941 and 1968 and a comparison with the serotypes observed in other countries over this period.

Classification, by agglutinogens, of 634 isolates of Bordetella pertussis collected from 1971 to 1968 in Great Britain demonstrated that a change from a predominantly 1,2,0,4 serotype (75% of those examined during 1941-4) to a predominantly 1,0,3,0 serotype (73% of those examined during 1966-8) occurred sometime after 1953. Furthermore, evidence from the examination of isolates collected between 1941 and 1953 suggests that the change may have been gradual. Isolates of serotype 1,2,3,4 made up 20-30% of the total of our cross-country selection for the periods 1941-4, 1946-9, 1950-3 and 1966-8, but over shorter periods in individual areas the percentage varied from negligible to as high as half of those isolated.

The influence of the route of immunization on the protection of mice infected intracerebrally with Bordetella pertussis.

The development of immunity in mice to Bordetella pertussis induced by intracerebral, intravenous or intraperitoneal vaccination was analysed in terms of the viable bacteria in the brain after intracerebral challenge, the serum antibodies, and protection against the sublethal infection of the lung that follows intranasal inoculation.A vaccine introduced intracerebrally was five to ten times more effective than that given intraperitoneally or intravenously, as measured for each route by the amount of vaccine required to protect half the mice against an intracerebral challenge 14 days later (ImD 50). Intracerebral vaccination induced higher antibody titres than vaccination by the other two routes.