Immunity To Haemophilus InfluenzaeType B: The Nature Of The Bactericidal Antibody In Human Blood

Abstract

It has been suggested that the bactericidal antibody associated with immunity to acute primary Haemophilus influenzae infections is that produced against the capsular antigen of H. influenzae type b. In a previous study, however, the bactericidal and the type-b capsular antibodies were found to have different age-distributions. In the present studies the age-distributions of children with bactericidal antibody and of those with agglutinins against non-capsulated strains were found to be similar. Furthermore, it was possible to absorb type-b bactericidins from rabbit antisera with non-capsulated strains without removing the type-b capsular antibody. These findings, together with other evidence in the literature, suggest that the antigen responsible for the production of the bactericidal antibody is somatic and is possessed by non-capsulated strains, although attempts to produce type-b bactericidins in rabbits immunised with these non-capsulated strains were unsuccessful.