Bactericidal activity of serum for Klebsiella rhinoscleromatis: studies on serum from a patient with rhinoscleroma and sera deficient in antibody or complement.

The in-vitro bactericidal effect of serum for Klebsiella rhinoscleromatis was tested. Experiments with C2-deficient and hypogammaglobulinaemic human sera suggested that killing depended on activation of the classical complement pathway, although the alternative pathway probably amplified the effect. Serum from a patient with active rhinoscleroma, and another cured of the disease, showed normal killing.