Evaluation of the Immunogenicity of Diphtheria Toxoid Conjugated to Salmonella Typhimurium-Derived OPS in a Mouse Model: A Potential Vaccine Candidate Against Salmonellosis
نویسندگان
1 Department of Microbiology, Zanjan Branch, Islamic Azad University, Zanjan, IR Iran
2 Department of Medical Microbiology, Tehran University of Medical Sciences, Tehran, IR Iran
3 Department of Medical Microbiology, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
4 Department of Medical Microbiology, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
5 Department of Microbiology, Kurdistan Science and Research Branch, Islamic Azad University, Sanandaj, IR Iran
6 Department of Pathobiology, Division of Microbiology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
7 Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, IR Iran
8 Department of Immunology, Tehran University of Medical Sciences, Tehran, IR Iran
9 Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
10 Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
doi
چکیده
Background: Salmonella enterica serovar Typhimurium (S. Typhimurium) causes gastroenteritis in humans and paratyphoid diseasein some animals. Given the emergence of antibiotic resistance, vaccines are more effective than chemotherapy in disease control.Objectives: The aim of this experimental study was to evaluate the immunogenicity of diphtheria toxoid (DT) conjugated with S.Typhimurium -derived OPS (O side chain isolation) in mice to determine its potential as a vaccine candidate against salmonellosis.Materials and Methods: Lipopolysaccharide (LPS) was extracted from the bacterial strain. After isolation of the O side chain of LPS,detoxification, and conjugation of the detoxified OPS samples with DT, pyrogenicity, toxicity, and sterility tests were performed. Tovaccination, four groups of female Balb/c mice were used in an immunization test. Antibody responses were measured by the ELISAmethod. Challenging processes were performed to analyze the efficacy of the OPS-DT compound.Results: Two weeks after the first vaccination dose, there was no significant difference in the antibody titers of the OPS and OPS-DTgroups. However, after the second and third doses, the antibody titers of the OPS-DT group increased significantly compared withthose of the control groups (P < 0.001). The induction of anti-OPS antibodies was as follows: OPS-DT>OPS. The most anti-OPS IgGantibody was IgG1. Challenging procedure showed successful protective characteristics in clinical examinations.Conclusions: The results indicated that DT increased anti-OPS antibodies against the OPS-DT compound. The antibody responseto OPS-DT was greater than that to OPS alone. We conclude that OPS-DT is an appropriate and acceptable vaccine candidate againstsalmonellosis.
