ANTIBODY RESPONSE TO INFECTIONS WITH THE NEWLY CLASSIFIED TYPES OF PNEUMOCOCCI (COOPER) 1

Abstract

2/3 of recovered pneumonia patients infected with 11 different types of pneumococci, including 9 of the newly classified types (Cooper), had antibodies for the homologous type. Results were similar in patients with broncho- and with lobar-pneumonia. A number of patients who died also had such antibodies late in the disease. Occasional patients with acute respiratory infections, without demonstrable pneumonia, also showed antibodies for the pneu-mococcus type recovered from their sputa. The specificity of the immune response was demonstrated by the failure, in such instances, to find antibodies for the other common types and by the specific absorption of the antibodies with pneumococci of the homologous and not the heterologous type. A few cases had antibodies against types other than the ones isolated from their sputum. Most of these represented cross-agglutinations with related types, particularly III and VIII. In patients from whom more than 1 type of pneumococcus was isolated, immunity was usually present against only 1 of the types.