An indirect fluorescent-antibody technique for study of uncomplicated gonorrhea. II. Selection and characterization of the strain of Neisseria gonorrhoeae used as antigen

By use of an indirect fluorescent-antibody (IFA) procedure, a number of strains of Neisseria gonorrhoeae were surveyed to identify several that reacted with sera from all of a group of patients with gonorrhea but not with sera from any of a group of normal individuals. Detailed studies showed that these broadly reactive strains possess antigenic features common to many strains of gonococci and that their antigenic features are not shared to a significant extent by other species of Neisseria. In the development of immunofluorescence tests for gonococcal antibodies, the selection of the strain of Neisseria gonorrhoeae used as antigen is cmcial. It is important that the strain chosen have antigenic groups broadly representative of gono-cocci, but that the strain react as little as possible with antibodies to other Neisseria. The studies that governed our selection of a particular strain of N. gonorrhoeae for use in an indirect fluorescent-antibody (IFA) technique are presented. They give evidence that certain strains of N. gonorrhoeae may be identified as represen-tative of the species, and that these strains show little cross-reactivity with other Neisseria species. Materials and Methods Antigens. With the exception of strain F62 type 1, all gonococcal strains used were from pri-mary isolates recently obtained from infected pa-tients and grown on Thayer-Martin selective me-dium. Isolates were further identified by gram Received for publication June 9, 1972, and in revise