Immunogenicity of ribosomal preparations from Neisseria gonorrhoeae

Abstract

Protection against gonococcal infection was obtained by immunization with ribosomal preparations from Neisseria gonorrhoeae. Ribosomes were isolated from disrupted cells by differential ultracentrifugation and treatment of the microsomal fraction with 0.25% sodium dodecyl sulfate. The isolated ribosomal preparations contained 55% ribonucleic acid, 39% protein, and 0.35% carbohydrate. The ribosomal preparations contained small amounts of endotoxin as determined by thiobarbituric acid- and lead acetate-sensitized mice assays. Guinea pigs immunized subcutaneously with ribosomal preparations were challenged intrachamberially with 10(7) colony-forming units of N. gonorrhoeae, and protection was assessed by clearance of the organism from subcutaneous chambers. The ribosomal preparations elicited significant protection, which was enhanced by incoporation of the immunogen into adjuvant. This protection was comparable to that obtained with whole cells. Treatment with proteolytic enzymes destroyed the protective effect of the ribosomal preparations, but ribonuclease had no measurable effect. Passive hemagglutination and immunodiffusion tests with sera from immunized animals demonstrated the presence of antibody to the ribosomal antigens. Results of adsorption of antiribosomal sera with enzyme-treated ribosomal preparations also indicated the protein nature of the immunogen. These results indicate that protein associated with the gonococcal ribosomal preparation is the major protective immunogen. The role of endotoxin contamination in the immunogenicity of gonococcal ribosomal preparations warrants further investigation.

Characterization of the immune response in subcutaneous chambers of guinea pigs immunized with a ribosomal preparation from Neisseria gonorrhoeae

“…Previous work with the guinea pig subcutaneous (s.c.) chamber model has demonstrated the ability of gonococcal ribosomal preparations to elicit a protective immune response to a subsequent challenge with Neisseria gonorrhoeae (8,9). In agreement with others (1,5,6,15,27), the protective response seen in the s.c. chamber model correlated with the presence of hemagglutinating and bactericidal antibodies in the serum of immunized animals.…”

“…Female Hartley guinea pigs weighing approximately 600 g were used throughout the study. Each guinea pig was implanted with two dorsal s.c. tube chambers of modified polyallomer as previously described (8).…”

“…Preparation of ribosomes. The ribosomal preparations were prepared by a modification of the method of Youmans and Youmans (28) as previously described (8,9).…”

“…Immunization and challenge of guinea pigs. Guinea pigs were immunized s.c. with 1 mg of ribosomal preparation as previously described (8,9) with Freund incomplete adjuvant. For the immunodiffusion assay, sera were obtained from guinea pigs immunized intraperitoneally with a second injection of ribosomal material (200 jig of protein) without Freund incomplete adjuvant 20 days after the primary immunization.…”

“…Saline was used for the suspending medium to minimize the amount of medium-induced inflammation in the chamber. Evaluation of the protection afforded to immunized guinea pigs was determined as previously described (8,9).…”