Relationship of Serogroups of Neisseria meningitidis I. Microagglutination, Gel Diffusion, and Slide Agglutination Studies of Meningococcal Antisera Before and After Absorption with RAS-10 Strain of Meningococci.

Microagglutination tests were used to show the relationship of a nongroupable strain of Neisseria meningitidis (RAS-10) to other serological groups. RAS-10 antiserum has been prepared and studied for the first time. Antibodies to the RAS-10 strain were shown to be present in many grouping antisera obtained from different sources. These antibodies were absorbed from antisera to heterologous sero-groups with the RAS-10 strain. This procedure was shown to make antisera more specific by eliminating serological cross-reactions and false grouping of RAS-10 strains. Antisera before and after absorption with RAS-10 cells were studied by using double diffusion in gels. An antigen-antibody precipitation line for the RAS-10 meningococci was shown to be removed by this procedure. Antiserum to group 29E meningococci was absorbed with group Z cells, and precipitation lines for Z cells were removed. Group 29E antiserum agglutinated group 29E and group Z cells in the slide agglutination test but was specific for group 29E cells in this test after absorption with group Z cells.