The role of surface antigens in the protective potency of Bordetella pertussis suspensions as measured by the intracerebral challenge technique in mice

The growth of different strains of Bordetella pertussis on a variety of media frequently leads to the loss of the surface antigens known as Andersen’s factors 1, 2 and 3. When such suspensions were used as vaccines they were found to be as protective to mice challenged with Bord. pertussis strain 18/323 by the intracerebral route as the parent strains grown in the conventional way and possessing these antigens. Conversely, vaccines prepared from strains of Bord. bronchiseptica and Bord. parapertussis showed poor protection against Bord. pertussis, although they shared type-7 antigen with it.

When antisera were prepared in rabbits by means of suspensions rich in type 1, 2 and 3 antigens and compared with sera prepared against suspensions lacking these factors no clear correlation was found in the protective effect. Some sera rich in agglutinins and others virtually devoid of them proved equally protective in the passive immunity test in mice.

It is therefore suggested that Andersen’s agglutinogens 1, 2, 3 and 7 play no part in the protective effect of vaccines. Some other antigen or antigens must be associated with the protection of mice and presumably also of children.