The Inability of the Capsular Material of Haemophilus pertussis to produce Protective Antisera

Abstract

Mice were inoculated intracerebrally with 24-hr. cultures of H. pertussis, killed on the 7th day, and the brains pooled and cultured on many BG plates. From this growth 4 types of prepns. were made[long dash](1) Growth suspended in dist. water, (2) Cells washed 3 times, (3) Supernatant from first washing concd. and containing capsular material, and (4) growth subcultured on BG medium for 6 months. Using rabbits, antisera against these 4 were prepd., and each one tested for agglutinins, complement-fixing antibodies, antitoxin, and protection for mice. No antitoxin was detected in any of the sera. Sera prepd. against the bacterial suspensions had higher agglutinating and complement-fixing titers than those prepd. against the concd. washings. Mice were protected equally with the first 3 antisera, while the antisera prepd. against the concd. washings gave very little protection. The expts. indicate that the antigens of H. pertussis producing agglutinating, complement-fixing and protective antibodies are somatic rather than capsular.