The effect of the antigen which elicits the bactericidal antibody and of the mouse-protective antigen on the growth of Bordetella pertussis in the mouse brain.

The effect of antigens of Bordetella pertussis and their antibodies on brain infections by B. pertussis in mice are suppression of an infection immediately, so that the initial 90% loss due to leakage from the brain is maintained or the numbers of bacteria are reduced even further, sometimes with complete sterilization particularly after a small lethal challenge of 10 LD 50 (mechanism 1), and a delayed antibacterial activity in vivo which does not begin until 3 days after challenge (mechanism 2). The first, immediate reaction is over in 2-3 days; the second is maintained from 3-4 days onwards, and results in elimination of the bacteria and protection of mice.

The effects of humoral, cellular and non-specific immunity on intracerebral Bordetella pertussis infections in mice.

When mice were injected intracerebrally with doses of Bordetella pertussis vaccine greater than 5 ImD 50 and challenged intracerebrally 14 days later with virulent B. pertussis there was an immediate reduction in the numbers of organisms. An analysis of this in vivo bactericidal effect has shown that large doses of an unrelated vaccine, Salmonella typhosa, equivalent in cell mass to about 50 ImD 50 of B.

The antibody activities of 19S and 7S fractions from rabbit antisera to Bordetella pertussis.

antisera were fractionated on Sephadex G-200 to give 19S and 7S globulins, the latter refractionated on DEAE-cellulose, and the antibody properties of the two purified materials compared. The minimal weights of 19S and 7S globulins required to neutralize haemagglutinin and to protect mice against an intranasal challenge causing lung infection were similar. In agglutination 7S globulin was 1.