Immunological Relation Between Serum Antibodies Against Pneumolysin and Against Streptolysin O

Abstract

The immunological relation between serum antibodies to pneumolysin and to streptolysin O was studied in patients with pneumococcal pneumonia (n=40), patients with infections due to β‐haemolytic streptococci (n=35), healthy human controls (n=60) and in rabbits immunized with pneumolysin. There was no correlation between anti‐pneumolysin and anti‐streptolysin O titers (r=‐0.279). The distribution of anti‐pneumolysin titers in patients with high anti‐streptolysin O titers did not differ from healthy controls. However, there was a tendency to increased or rising anti‐streptolysin O titers in patients with pneumococcal infection. Antibodies obtained during pneumococcal infection might thus give false‐positive reactions in the streptolysin O neutralization test. Serum antibodies to streptolysin O do not cross‐react with pneumolysin in an ELISA. The pneumolysin ELISA for detection of pneumococcal disease will therefore not be disturbed by false‐positive reactions due to antibodies directed against β‐haemolytic streptococci.