2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections
| Format: | General Document |
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| _version_ | 1860798005887631360 |
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| building | INTELEK Repository |
| collection | Online Access |
| collectionurl | https://intelek.unisza.edu.my/intelek/pages/search.php?search=!collection3 |
| copyright | Copyright©PWB2025 |
| country | Malaysia |
| date | 2019-10-06 |
| format | General Document |
| id | 15398 |
| institution | UniSZA |
| internalnotes | Sila masukkan subject wajib Dissertations, Academic. Terima kasih... |
| originalfilename | IMMUNO~1.PDF |
| person | Amonov Malik |
| recordtype | oai_dc |
| resourceurl | https://intelek.unisza.edu.my/intelek/pages/view.php?ref=15398 |
| sourcemedia | Server storage Scanned document |
| spelling | 15398 https://intelek.unisza.edu.my/intelek/pages/view.php?ref=15398 https://intelek.unisza.edu.my/intelek/pages/search.php?search=!collection3 General Document Malaysia Library Staff (Top Management) Library Staff (Management) Library Staff (Support) Terengganu Faculty of Medicine English application/pdf 1.5 224 Server storage Scanned document Universiti Sultan Zainal Abidin UniSZA Private Access Universiti Sultan Zainal Abidin SAMBox 2.3.4; modified using iTextSharp™ 5.5.10 ©2000-2016 iText Group NV (AGPL-version) IMMUNO~1.PDF 2019-10-06 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections Streptococcus pneumoniae—Immunology Amonov Malik Immunogenicity Pathogenicity Copyright©PWB2025 Annually Streptococcus pneumoniae (S. pneumoniae) causes 0.7-1.0 million deaths among children aged less than 5 years worldwide. The bacterium is the most common cause of pneumonia, acute otitis media and meningitis. Currently used polysaccharide based pneumococcal vaccines significantly reduce the disease burden of S. pneumoniae but the high production cost and lower effectiveness of these vaccines limit their use, particularly in middle and low-income countries. Development of live attenuated vaccines (LAV) of S. pneumoniae is one of the alternatives that are currently being explored. The main objective of this study is to construct LAV of S. pneumoniae by cpsE and endA gene knockouts and to investigate the immunogenicity of these candidate vaccine strains in a mouse model. Both cpsE and endA genes are known virulence factors with cpsE responsible for capsule formation and endA confers resistance to neutrophil clearance. Three candidate S. pneumoniae vaccine strains were genetically-engineered from the S. pneumoniae wild-type D39 strain by introducing gene knockouts of the cpsE and endA genes, leading to recombinant strains designated SPC (with the cpsE::tetL knockout), SPE (endA::aphA-3 knockout) and SPEC (double mutant with cpsE::tetL and endA::aphA-3). Biofilm formation and growth kinetics of the candidate vaccine strains were studied in vitro. Intranasal colonization potential and immunogenicity was studied on BALB/c mice. Immune protection was studied by survival time of mice challenged with a high dose of the wild-type strain. The capsule gene (cpsE) knockout strains (SPC and SPEC) had significantly lowered peak bacterial density and colonization. Conversely, SPC and SPEC had increased biofilm formation comparing to the wild-type D39 strain. However, the endA gene knockout strain, SPE, did not significantly differ from the wild-type strain in growth, colonization and biofilm assays. All constructed vaccine strains were able to induce significantly high serum IgG and mucosal IgA antibody response in mice; however, the double mutant strain was able to protect mice from high dose mucosal challenge of the wild-type. Furthermore, the SPEC strain showed 23-fold attenuation of virulence compared to the wild-type D39 strain. Although all vaccine candidates induced significantly high mucosal IgA and serum IgG, only the double mutant strain, SPEC, was able to confer significant protection in high dose wild-type mucosal challenge and showed attenuated virulence. Thus, the SPEC strain could be a promising candidate for further development of a live attenuated vaccine for S. pneumoniae. Dissertations, Academic Sila masukkan subject wajib Dissertations, Academic. Terima kasih... CPSE Gene Mutation Streptococcus Pneumoniae Thesis |
| spellingShingle | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| state | Terengganu |
| subject | Streptococcus pneumoniae—Immunology Dissertations, Academic |
| summary | Annually Streptococcus pneumoniae (S. pneumoniae) causes 0.7-1.0 million deaths among children aged less than 5 years worldwide. The bacterium is the most common cause of pneumonia, acute otitis media and meningitis. Currently used polysaccharide based pneumococcal vaccines significantly reduce the disease burden of S. pneumoniae but the high production cost and lower effectiveness of these vaccines limit their use, particularly in middle and low-income countries. Development of live attenuated vaccines (LAV) of S. pneumoniae is one of the alternatives that are currently being explored. The main objective of this study is to construct LAV of S. pneumoniae by cpsE and endA gene knockouts and to investigate the immunogenicity of these candidate vaccine strains in a mouse model. Both cpsE and endA genes are known virulence factors with cpsE responsible for capsule formation and endA confers resistance to neutrophil clearance. Three candidate S. pneumoniae vaccine strains were genetically-engineered from the S. pneumoniae wild-type D39 strain by introducing gene knockouts of the cpsE and endA genes, leading to recombinant strains designated SPC (with the cpsE::tetL knockout), SPE (endA::aphA-3 knockout) and SPEC (double mutant with cpsE::tetL and endA::aphA-3). Biofilm formation and growth kinetics of the candidate vaccine strains were studied in vitro. Intranasal colonization potential and immunogenicity was studied on BALB/c mice. Immune protection was studied by survival time of mice challenged with a high dose of the wild-type strain. The capsule gene (cpsE) knockout strains (SPC and SPEC) had significantly lowered peak bacterial density and colonization. Conversely, SPC and SPEC had increased biofilm formation comparing to the wild-type D39 strain. However, the endA gene knockout strain, SPE, did not significantly differ from the wild-type strain in growth, colonization and biofilm assays. All constructed vaccine strains were able to induce significantly high serum IgG and mucosal IgA antibody response in mice; however, the double mutant strain was able to protect mice from high dose mucosal challenge of the wild-type. Furthermore, the SPEC strain showed 23-fold attenuation of virulence compared to the wild-type D39 strain. Although all vaccine candidates induced significantly high mucosal IgA and serum IgG, only the double mutant strain, SPEC, was able to confer significant protection in high dose wild-type mucosal challenge and showed attenuated virulence. Thus, the SPEC strain could be a promising candidate for further development of a live attenuated vaccine for S. pneumoniae. |
| title | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| title_full | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| title_fullStr | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| title_full_unstemmed | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| title_short | 2019_Immunogenicity and Pathogenicity of Enda And CPSE Gene-Mutated Streptococcus Pneumoniae Strain as a Potential Live Attenuated Vaccine Candidate Against Pneumococcal Infections |
| title_sort | 2019_immunogenicity and pathogenicity of enda and cpse gene-mutated streptococcus pneumoniae strain as a potential live attenuated vaccine candidate against pneumococcal infections |