Method for detecting antibody formation to Neisseria gonorrhoeae

The use of Concanavalin A as a coupling agent for sensitization of sheep erythrocytes with an alkaline extract of Neisseria gonorrhoeae organisms is described in this paper. The sensitized erythrocytes were used in a plaque assay for enumeration of antibody-producing cells and in hemagglutination and hemolysin tests for determination of serum antibody. Rabbits were immunized intraperitoneally, intravenously, or via the footpad with viable N. gonorrhoeae organisms. Plaque-forming cells were found in draining lymph nodes and in the spleens of these rabbits. The cells from some rabbits also lysed sheep erythrocytes coated with an alkaline extract prepared from Neisseria meningitidis organisms. No antibody-producing cells were found in the lymphoid tissues of normal rabbits. Rabbits immunized by all three routes developed high hemagglutination and hemolysin titers. Hemolysin titers were significantly higher than hemagglutination titers when both tests were performed on the same serum samples. Pooled antiserum from these rabbits also lysed erythrocytes coated with a meningococcal antigen, but titers for the specific immunizing species were higher.