Gamma-irradiation of Streptococcus pneumoniae for the use as an immunogenic whole cell vaccine

• Published in: The journal of microbiology 2018, 56(8), , pp.579-585
• Main Authors: Jwa, Min Yong, Jeong, Soyoung, Ko, Eun Byeol, Kim, A Reum, Kim, Hyun Young, Kim, Sun Kyung, Seo, Ho Seong, Yun, Cheol-Heui, Han, Seung Hyun
• Format: Article
• Language: English
• Subjects: Administration, Intranasal; Animals; Antibodies; Antibodies, Bacterial - analysis; Antibodies, Bacterial - blood; Biomedical and Life Sciences; Blood Bactericidal Activity; Capsular polysaccharides; Cholera; Cholera toxin; Deactivation; Developing countries; Disease control; Disease Models, Animal; Gamma Rays; Immune response; Immunity; Immunization; Immunogenicity; Inactivation; Irradiation; LDCs; Life Sciences; Methods; Mice; Mice, Inbred C57BL; Microbiology; Mucosal immunity; Opsonin Proteins - blood; Pneumococcal Infections - prevention & control; Pneumococcal Vaccines - administration & dosage; Pneumococcal Vaccines - immunology; Pneumococcal Vaccines - isolation & purification; Polysaccharides; Proteins; Respiratory Mucosa - immunology; Respiratory tract; Saccharides; Streptococcus infections; Streptococcus pneumoniae; Streptococcus pneumoniae - immunology; Streptococcus pneumoniae - radiation effects; Toxins; Treatment Outcome; Vaccines; Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - immunology; Vaccines, Inactivated - isolation & purification; Waterborne diseases; 생물학
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-018-8347-1

Streptococcus pneumoniae is a major respiratory pathogen that causes millions of deaths worldwide. Although subunit vaccines formulated with the capsular polysaccharides or their protein conjugates are currently-available, low-cost vaccines with wide serotype coverage still remain to be developed, especially for developing countries. Recently, gamma- irradiation has been considered as an effective inactivation method to prepare S. pneumoniae vaccine candidate. In this study, we investigated the immunogenicity and protective immunity of gamma-irradiated S. pneumoniae (r-SP), by comparing with heat-inactivated S. pneumoniae (h-SP) and formalin-inactivated S. pneumoniae (f-SP), both of which were made by traditional inactivation methods. Intranasal immunization of C57BL/6 mice with r-SP in combination with cholera toxin as an adjuvant enhanced S. pneumoniaespecific antibodies on the airway mucosal surface and in sera more potently than that with h-SP or f-SP under the same conditions. In addition, sera from mice immunized with r-SP potently induced opsonophagocytic killing activity more effectively than those of h-SP or f-SP, implying that r-SP could induce protective antibodies. Above all, immunization with r-SP effectively protected mice against S. pneumoniae infection. Collectively, these results suggest that gamma- irradiation is an effective method for the development of a killed whole cell pneumococcal vaccine that elicits robust mucosal and systemic immune responses.