Homocytotropic antibodies (IgE) to Neisseria gonorrhoeae in the rat and a cross-reactivity of heterologous gonococcal strains.

Outbred Wistar rats were immunised with a single intraperitoneal injection of a mixture of 30 mg of A1(OH)3 and 100microng of gonococcal zeolite antigen (ZA). Ten days after immunisation, ZA prepared from T1 and T4 colonies of Neisseria gonorrhoeae strain GC6 (GC6-T1 ZA and GC6-T4 ZA) were able to elicit a reaginic (IgE) response which declined to low levels by 35 days. There was a significant amount of histamine release from the mast cells of actively-sensitised rats on challenge with a specific gonococcal antigen. The antisera heated at a temperature of 56 degrees C for four hours failed to elicit a passive cutaneous anaphylaxis (PCA) reaction, indicating a lack of IgGa antibody. In addition antisera to GC6-T1 ZA gave a positive PCA reaction with GC6-T4 ZA and ZA prepared from T1 colonies of six heterologous gonococcal strains suggesting that these strains of N. gonorrhoeae share common antigenic determinants.