Serologic Relationship Among Meningococcal Strains in Norway

Summary

In direct bacterial agglutination experiments with 13 meningococcal strains isolated in Norway from 1952 to 1955, 3 distinct serologic types were observed. Two of the types corresponded to Group II and Group IIα, or Group B and Group C in the nomenclature proposed in 1950 by the Subcommittee of the Nomenclature Committee of the International Association of Microbiologists (1). The third type, that showed no agglutination in monovalent sera representative of Group I, Group II, and Group IIα, was provisionally named Type N.

Determination of the nitrogen quantities removed from homologous and heterologous antisera proved the presence of common antigenic substances in the 3 types. The distinct type difference was confirmed however. Strains from Type N appear to share some components with each of the other 2 types.

On cultivation of the microbes on immune serum agar plates, the specificity of a strain from Group IIα is associated with a “halo” phenomenon that is not observed in strains of the other 2 types.

An antigen sorption technique was used for the analysis. A method was established for extraction from meningococci substances that showed uniform and constant ability to render erythrocytes susceptible to the action of antibodies and complement. Common to the 3 meningococcal types was a serologically active nucleoprotein that was inactive in antigen sorption reaction.

The results from cross absorption with antigentreated erythrocytes were in agreement with the results of the quantitative agglutinin studies. The results have been summed up in a provisional theory of the relative antigenic constitution of the substances active in the antigen sorption reaction with meningococci.