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Shafaghi M, Bahadori Z, Barzi SM, Afshari E, Madanchi H, Mousavi SF, Shabani AA. A new candidate epitope-based vaccine against PspA PhtD of Streptococcus pneumoniae: a computational experimental approach. Front Cell Infect Microbiol 2023; 13:1271143. [PMID: 38035337 PMCID: PMC10684780 DOI: 10.3389/fcimb.2023.1271143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023] Open
Abstract
Introduction Pneumococcus is an important respiratory pathogen that is associated with high rates of death in newborn children and the elderly. Given the disadvantages of current polysaccharide-based vaccines, the most promising alternative for developing improved vaccines may be to use protein antigens with different roles in pneumococcus virulence. PspA and PhtD, highly immunogenic surface proteins expressed by almost all pneumococcal strains, are capable of eliciting protective immunity against lethal infections. Methods In this study using immunoinformatics approaches, we constructed one fusion construct (called PAD) by fusing the immunodominant regions of PspA from families 1 & 2 (PA) to the immunodominant regions of PhtD (PD). The objective of this project was to test the immunogenicity of the fusion protein PAD and to compare its protective activity against S. pneumoniae infection with PA or PD alone and a combination of PA and PD. The prediction of physicochemical properties, antigenicity, allergenicity, toxicity, and 3D-structure of the constructs, as well as molecular docking with HLA receptor and immune simulation were performed using computational tools. Finally, mice were immunized and the serum levels of antibodies/cytokines and functionality of antibodies in vitro were evaluated after immunization. The mice survival rates and decrease of bacterial loads in the blood/spleen were examined following the challenge. Results The computational analyses indicated the proposed constructs could be antigenic, non-allergenic, non-toxic, soluble and able to elicit robust immune responses. The results of actual animal experiments revealed the candidate vaccines could induce the mice to produce high levels of antibodies and cytokines. The complement-mediated bactericidal activity of antibodies was confirmed and the antibodies provided favorable survival in immunized mice after bacterial challenge. In general, the experimental results verified the immunoinformatics studies. Conclusion For the first time this report presents novel peptide-based vaccine candidates consisting of immunodominant regions of PspA and PhtD antigens. The obtained findings confirmed that the fusion formulation could be relatively more efficient than the individual and combination formulations. The results propose that the fusion protein alone could be used as a serotype-independent pneumococcal vaccine or as an effective partner protein for a conjugate polysaccharide vaccine.
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Affiliation(s)
- Mona Shafaghi
- Department of Medical Biotechnology, faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Zohreh Bahadori
- Department of Medical Biotechnology, faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | | | - Elnaz Afshari
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Hamid Madanchi
- Department of Medical Biotechnology, faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
- Drug Design and Bioinformatics Unit, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | | | - Ali Akbar Shabani
- Department of Medical Biotechnology, faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
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Carneiro GB, Castro JT, Davi M, Miyaji EN, Ladant D, Oliveira MLS. Immune responses and protection against Streptococcus pneumoniae elicited by recombinant Bordetella pertussis adenylate cyclase (CyaA) carrying fragments of pneumococcal surface protein A, PspA. Vaccine 2023:S0264-410X(23)00570-4. [PMID: 37236818 DOI: 10.1016/j.vaccine.2023.05.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023]
Abstract
Streptococcus pneumoniae is a common agent of important human diseases such as otitis media, pneumonia, meningitis and sepsis. Current available vaccines that target capsular polysaccharides induce protection against invasive disease and nasopharyngeal colonization in children, yet their efficacy is limited to the serotypes included in the formulations. The virulence factor Pneumococcal Surface Protein A (PspA) interacts with host immune system and helps the bacteria to evade phagocytosis. Due to its essential role in virulence, PspA is an important vaccine candidate. Here we have tested a delivery system based on the adenylate cyclase toxin of Bordetella pertussis (CyaA) to induce immune responses against PspA in mice. CyaA was engineered to express fragments of the N-terminal region of PspAs from clades 2 and 4 (A2 and A4) and the resulting proteins were used in immunization experiments in mice. The recombinant CyaA-A2 and CyaA-A4 proteins were able to induce high levels of anti-PspA antibodies that reacted with pneumococcal strains expressing either PspA2 or PspA4. Moreover, reactivity of the antibodies against pneumococcal strains that express PspAs from clades 3 and 5 (PspA3 and PspA5) was also observed. A formulation containing CyaA-A2 and CyaA-A4 was able to protect mice against invasive pneumococcal challenges with isolates that express PspA2, PspA4 or PspA5. Moreover, a CyaA-A2-A4 fusion protein induced antibodies at similar levels and with similar reactivity as the formulation containing both proteins, and protected mice against the invasive challenge. Our results indicate that CyaA-PspA proteins are good candidates to induce broad protection against pneumococcal isolates.
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Affiliation(s)
| | | | - Marilyne Davi
- Institut Pasteur, Université de Paris Cité, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Paris, France
| | | | - Daniel Ladant
- Institut Pasteur, Université de Paris Cité, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Paris, France.
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Shafaghi M, Bahadori Z, Madanchi H, Ranjbar MM, Shabani AA, Mousavi SF. Immunoinformatics-aided design of a new multi-epitope vaccine adjuvanted with domain 4 of pneumolysin against Streptococcus pneumoniae strains. BMC Bioinformatics 2023; 24:67. [PMID: 36829109 PMCID: PMC9951839 DOI: 10.1186/s12859-023-05175-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/06/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND Streptococcus pneumoniae (Pneumococcus) has remained a leading cause of fatal infections such as pneumonia, meningitis, and sepsis. Moreover, this pathogen plays a major role in bacterial co-infection in patients with life-threatening respiratory virus diseases such as influenza and COVID-19. High morbidity and mortality in over one million cases, especially in very young children and the elderly, are the main motivations for pneumococcal vaccine development. Due to the limitations of the currently marketed polysaccharide-based vaccines, non-serotype-specific protein-based vaccines have received wide research interest in recent years. One step further is to identify high antigenic regions within multiple highly-conserved proteins in order to develop peptide vaccines that can affect various stages of pneumococcal infection, providing broader serotype coverage and more effective protection. In this study, immunoinformatics tools were used to design an effective multi-epitope vaccine in order to elicit neutralizing antibodies against multiple strains of pneumococcus. RESULTS The B- and T-cell epitopes from highly protective antigens PspA (clades 1-5) and PhtD were predicted and immunodominant peptides were linked to each other with proper linkers. The domain 4 of Ply, as a potential TLR4 agonist adjuvant candidate, was attached to the end of the construct to enhance the immunogenicity of the epitope vaccine. The evaluation of the physicochemical and immunological properties showed that the final construct was stable, soluble, antigenic, and non-allergenic. Furthermore, the protein was found to be acidic and hydrophilic in nature. The protein 3D-structure was built and refined, and the Ramachandran plot, ProSA-web, ERRAT, and Verify3D validated the quality of the final model. Molecular docking analysis showed that the designed construct via Ply domain 4 had a strong interaction with TLR4. The structural stability of the docked complex was confirmed by molecular dynamics. Finally, codon optimization was performed for gene expression in E. coli, followed by in silico cloning in the pET28a(+) vector. CONCLUSION The computational analysis of the construct showed acceptable results, however, the suggested vaccine needs to be experimentally verified in laboratory to ensure its safety and immunogenicity.
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Affiliation(s)
- Mona Shafaghi
- grid.486769.20000 0004 0384 8779Department of Medical Biotechnology, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran ,grid.486769.20000 0004 0384 8779Research Center of Biotechnology, Semnan University of Medical Sciences, Semnan, Iran ,grid.420169.80000 0000 9562 2611Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Zohreh Bahadori
- grid.486769.20000 0004 0384 8779Department of Medical Biotechnology, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran ,grid.486769.20000 0004 0384 8779Research Center of Biotechnology, Semnan University of Medical Sciences, Semnan, Iran ,grid.420169.80000 0000 9562 2611Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Hamid Madanchi
- grid.486769.20000 0004 0384 8779Department of Medical Biotechnology, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran ,grid.486769.20000 0004 0384 8779Research Center of Biotechnology, Semnan University of Medical Sciences, Semnan, Iran ,grid.420169.80000 0000 9562 2611Drug Design and Bioinformatics Unit, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad Mehdi Ranjbar
- grid.418970.3Agricultural Research, Education, and Extension Organization (AREEO), Razi Vaccine and Serum Research Institute, Karaj, Iran
| | - Ali Akbar Shabani
- Department of Medical Biotechnology, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran. .,Research Center of Biotechnology, Semnan University of Medical Sciences, Semnan, Iran.
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Lane JR, Tata M, Briles DE, Orihuela CJ. A Jack of All Trades: The Role of Pneumococcal Surface Protein A in the Pathogenesis of Streptococcus pneumoniae. Front Cell Infect Microbiol 2022; 12:826264. [PMID: 35186799 PMCID: PMC8847780 DOI: 10.3389/fcimb.2022.826264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/10/2022] [Indexed: 12/11/2022] Open
Abstract
Streptococcus pneumoniae (Spn), or the pneumococcus, is a Gram-positive bacterium that colonizes the upper airway. Spn is an opportunistic pathogen capable of life-threatening disease should it become established in the lungs, gain access to the bloodstream, or disseminate to vital organs including the central nervous system. Spn is encapsulated, allowing it to avoid phagocytosis, and current preventative measures against infection include polyvalent vaccines composed of capsular polysaccharide corresponding to its most prevalent serotypes. The pneumococcus also has a plethora of surface components that allow the bacteria to adhere to host cells, facilitate the evasion of the immune system, and obtain vital nutrients; one family of these are the choline-binding proteins (CBPs). Pneumococcal surface protein A (PspA) is one of the most abundant CBPs and confers protection against the host by inhibiting recognition by C-reactive protein and neutralizing the antimicrobial peptide lactoferricin. Recently our group has identified two new roles for PspA: binding to dying host cells via host-cell bound glyceraldehyde 3-phosphate dehydrogenase and co-opting of host lactate dehydrogenase to enhance lactate availability. These properties have been shown to influence Spn localization and enhance virulence in the lower airway, respectively. Herein, we review the impact of CBPs, and in particular PspA, on pneumococcal pathogenesis. We discuss the potential and limitations of using PspA as a conserved vaccine antigen in a conjugate vaccine formulation. PspA is a vital component of the pneumococcal virulence arsenal - therefore, understanding the molecular aspects of this protein is essential in understanding pneumococcal pathogenesis and utilizing PspA as a target for treating or preventing pneumococcal pneumonia.
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Affiliation(s)
| | | | | | - Carlos J. Orihuela
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States
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Kiyono H, Yuki Y, Nakahashi-Ouchida R, Fujihashi K. Mucosal vaccines: wisdom from now and then. Int Immunol 2021; 33:767-774. [PMID: 34436595 PMCID: PMC8633596 DOI: 10.1093/intimm/dxab056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/25/2021] [Indexed: 12/29/2022] Open
Abstract
The oral and nasal cavities are covered by the mucosal epithelium that starts at the beginning of the aero-digestive tract. These mucosal surfaces are continuously exposed to environmental antigens including pathogens and allergens and are thus equipped with a mucosal immune system that mediates initial recognition of pathogenicity and initiates pathogen-specific immune responses. At the dawn of our scientific effort to explore the mucosal immune system, dental science was one of the major driving forces as it provided insights into the importance of mucosal immunity and its application for the control of oral infectious diseases. The development of mucosal vaccines for the prevention of dental caries was thus part of a novel approach that contributed to building the scientific foundations of the mucosal immune system. Since then, mucosal immunology and vaccines have gone on a scientific journey to become one of the major entities within the discipline of immunology. Here, we introduce our past and current efforts and future directions for the development of mucosal vaccines, specifically a rice-based oral vaccine (MucoRice) and a nanogel-based nasal vaccine, with the aim of preventing and controlling gastrointestinal and respiratory infectious diseases using the interdisciplinary fusion of mucosal immunology with agricultural science and biomaterial engineering, respectively.
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Affiliation(s)
- Hiroshi Kiyono
- Division of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan
- Department of Medicine, School of Medicine and CU-UCSD Center for Mucosal Immunology, Allergy and Vaccines, University of California, San Diego, San Diego, CA, USA
| | - Yoshikazu Yuki
- Division of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Rika Nakahashi-Ouchida
- Division of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kohtaro Fujihashi
- Division of Clinical Vaccinology, International Research and Development Center for Mucosal Vaccines, Institute of Medical Science, University of Tokyo, Tokyo, Japan
- Department of Pediatric Dentistry, The University of Alabama at Birmingham, Birmingham, AL, USA
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Nakahashi-Ouchida R, Uchida Y, Yuki Y, Katakai Y, Yamanoue T, Ogawa H, Munesue Y, Nakano N, Hanari K, Miyazaki T, Saito Y, Umemoto S, Sawada SI, Mukerji R, Briles DE, Yasutomi Y, Akiyoshi K, Kiyono H. A nanogel-based trivalent PspA nasal vaccine protects macaques from intratracheal challenge with pneumococci. Vaccine 2021; 39:3353-3364. [PMID: 34016473 DOI: 10.1016/j.vaccine.2021.04.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/20/2021] [Accepted: 04/30/2021] [Indexed: 12/17/2022]
Abstract
Current polysaccharide-based pneumococcal vaccines are effective but not compatible with all serotypes of Streptococcus pneumoniae. We previously developed an adjuvant-free cationic nanogel nasal vaccine containing pneumococcal surface protein A (PspA), which is expressed on the surfaces of all pneumococcal serotypes. Here, to address the sequence diversity of PspA proteins, we formulated a cationic nanogel-based trivalent pneumococcal nasal vaccine and demonstrated the vaccine's immunogenicity and protective efficacy in macaques by using a newly developed nasal spray device applicable to humans. Nasal vaccination of macaques with cationic cholesteryl pullulan nanogel (cCHP)-trivalent PspA vaccine effectively induced PspA-specific IgGs that bound to pneumococcal surfaces and triggered complement C3 deposition. The immunized macaques were protected from pneumococcal intratracheal challenge through both inhibition of lung inflammation and a dramatic reduction in the numbers of bacteria in the lungs. These results demonstrated that the cCHP-trivalent PspA vaccine is an effective candidate vaccine against pneumococcal infections.
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Affiliation(s)
- Rika Nakahashi-Ouchida
- Division of Mucosal Vaccines, International Research and Development Center for Mucosal Vaccine, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan; Department of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Yohei Uchida
- Division of Mucosal Vaccines, International Research and Development Center for Mucosal Vaccine, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Yoshikazu Yuki
- Division of Mucosal Vaccines, International Research and Development Center for Mucosal Vaccine, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan; HanaVax Inc., Tokyo 103-0012, Japan
| | - Yuko Katakai
- Department of Medical Science Project Planning and Support, The Corporation for Production and Research of Laboratory Primates, Ibaraki, 305-0843, Japan
| | - Tomoyuki Yamanoue
- Division of Mucosal Vaccines, International Research and Development Center for Mucosal Vaccine, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Hiromi Ogawa
- Department of Medical Science Project Planning and Support, The Corporation for Production and Research of Laboratory Primates, Ibaraki, 305-0843, Japan
| | - Yoshiko Munesue
- Department of Medical Science Project Planning and Support, The Corporation for Production and Research of Laboratory Primates, Ibaraki, 305-0843, Japan
| | - Nozomi Nakano
- Department of Medical Science Project Planning and Support, The Corporation for Production and Research of Laboratory Primates, Ibaraki, 305-0843, Japan
| | - Kouji Hanari
- Department of Medical Science Project Planning and Support, The Corporation for Production and Research of Laboratory Primates, Ibaraki, 305-0843, Japan
| | | | - Yuki Saito
- Toko Yakuhin Kogyo Co., Ltd., 930-0211, Japan
| | - Shingo Umemoto
- Department of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan; Faculty of Medicine, Department of Otorhinolaryngology and Head and Neck Surgery, Oita University, Oita 879-5593, Japan
| | - Shin-Ichi Sawada
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Reshmi Mukerji
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294-2170, United States
| | - David E Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294-2170, United States
| | - Yasuhiro Yasutomi
- Laboratory of Immunoregulation and Vaccine Research, Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, 305-0843, Japan
| | - Kazunari Akiyoshi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Hiroshi Kiyono
- Department of Mucosal Immunology, IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan; HanaVax Inc., Tokyo 103-0012, Japan; Mucosal Immunology and Allergy Therapeutics, Institute for Global Prominent Research, Chiba University, Chiba 263-8522, Japan; CU-UCSD Center for Mucosal Immunology, Allergy and Vaccine (cMAV), Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0063, United States.
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The Modified Surface Killing Assay Distinguishes between Protective and Nonprotective Antibodies to PspA. mSphere 2019; 4:4/6/e00589-19. [PMID: 31826968 PMCID: PMC6908419 DOI: 10.1128/msphere.00589-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The most important finding of this study is that the MSKA can be used as an in vitro functional assay. Such an assay will be critical for the development of PspA-containing vaccines. The other important findings relate to the locations and nature of the protection-eliciting epitopes of PspA. There are limited prior data on the locations of protection-eliciting PspA epitopes, but those data along with the data presented here make it clear that there is not a single epitope or domain of PspA that can elicit protective antibody and there exists at least one region of the αHD which seldom elicits protective antibody. Moreover, these data, in concert with prior data, strongly make the case that protective epitopes in the αHD are highly conformational (≥100-amino-acid fragments of the αHD are required), whereas at least some protection-eliciting epitopes in the proline-rich domain are encoded by ≤15-amino-acid sequences. Pneumococcal surface protein A (PspA) elicits antibody protective against lethal challenge by Streptococcus pneumoniae and is a candidate noncapsular antigen for inclusion in vaccines. Evaluation of immunity to PspA in human trials would be greatly facilitated by an in vitro functional assay able to distinguish protective from nonprotective antibodies to PspA. Mouse monoclonal antibodies (MAbs) to PspA can mediate killing by human granulocytes in the modified surface killing assay (MSKA). To determine if the MSKA can distinguish between protective and nonprotective MAbs, we examined seven MAbs to PspA. All bound recombinant PspA, as detected by enzyme-linked immunosorbent assay and Western blotting; four gave strong passive protection against fatal challenge, two were nonprotective, and the seventh one only delayed death. The four that were able to provide strong passive protection were also most able to enhance killing in the MSKA, the two that were not protective in mice were not effective in the MSKA, and the MAb that was only weakly protective in mice was weakly effective in the MSKA (P < 0.001). One of the four most protective MAbs tested reacted to the proline-rich domain of PspA. Two of the other most protective MAbs and the weakly protective MAb reacted with a fragment from PspA’s α-helical domain (αHD), containing amino acids (aa) 148 to 247 from the N terminus of PspA. The fourth highly protective MAb recognized none of the overlapping 81- or 100-aa fragments of PspA. The two nonprotective MAbs recognized a more N-terminal αHD fragment (aa 48 to 147). IMPORTANCE The most important finding of this study is that the MSKA can be used as an in vitro functional assay. Such an assay will be critical for the development of PspA-containing vaccines. The other important findings relate to the locations and nature of the protection-eliciting epitopes of PspA. There are limited prior data on the locations of protection-eliciting PspA epitopes, but those data along with the data presented here make it clear that there is not a single epitope or domain of PspA that can elicit protective antibody and there exists at least one region of the αHD which seldom elicits protective antibody. Moreover, these data, in concert with prior data, strongly make the case that protective epitopes in the αHD are highly conformational (≥100-amino-acid fragments of the αHD are required), whereas at least some protection-eliciting epitopes in the proline-rich domain are encoded by ≤15-amino-acid sequences.
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Combined prime-boost immunization with systemic and mucosal pneumococcal vaccines based on Pneumococcal surface protein A to enhance protection against lethal pneumococcal infections. Immunol Res 2019; 67:398-407. [PMID: 31773490 DOI: 10.1007/s12026-019-09107-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Limited protective effects of commercially available vaccines necessitate the development of novel pneumococcal vaccines. We recently reported a pneumococcal systemic vaccine containing two proteins, Pneumococcal surface protein A (PspA of family 1 and 2) and a bacterium-like particle-based pneumococcal mucosal vaccine containing PspA2 and PspA4 fragments, both eliciting broad protective immune responses. We had previously reported that subcutaneous (s.c.+s.c.+s.c.) immunization with the systemic vaccine induced more pronounced humoral serum IgG responses, while intranasal (i.n.+i.n.+i.n.) immunization with the mucosal vaccine elicited a more pronounced mucosal secretory IgA (sIgA) response. We hypothesized that a combinatorial administration of the two vaccines might elicit more pronounced and broader protective immune responses. Therefore, this study aimed to determine the efficacy of combinatorial prime-boost immunization using both systemic and mucosal vaccines for a pneumococcal infection. Combinatorial prime-boost immunization (s.c.+i.n. and i.n.+s.c.) induced not only IgG, but also mucosal sIgA production at high levels. Systemic priming and mucosal boosting immunization (s.c.+i.n.) provided markedly better protection than homologous prime-boost immunization (s.c.+s.c.+s.c. and i.n.+i.n.+i.n.). Moreover, it induced more robust Th1 and Th17 cell-mediated immune responses than mucosal priming and systemic boosting immunization (i.n.+s.c.). These results indicate that combinatorial prime-boost immunization potentially induces a robust systemic and mucosal immune response, making it an optimal alternative for maximum protection against lethal pneumococcal infections.
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Immunization with proline rich region of pneumococcal surface protein A has no role in protection against Streptococcus pneumoniae serotype 19F. Microb Pathog 2019; 138:103761. [PMID: 31560974 DOI: 10.1016/j.micpath.2019.103761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 11/20/2022]
Abstract
Pneumococcal surface protein A (PspA) is one of the major virulence factors expressed by almost all pneumococcal serotypes and was suggested to be a promising universal vaccine candidate for all pneumococcal sero-groups. Here, we expressed and purified the proline-rich region (PR) of PspA and tested it as a recombinant vaccine against infection caused by a clinical isolate (SP19) of Streptococcus pneumoniae serotype 19F. Our results showed that BALB/c mice immunized with recombinant proline-rich (rPR) region showed a significant higher antibody titre against rPR region compared to control non-immunized group. However, immunized mice or mice recived polyclonal antibodies against rPR region challenged via the intra-peritoneal route with a lethal dose of SP19 isolate showed no significant difference in survival compared to control non-immunized group. These results suggested that, immunization of BALB/c mice with rPR region of PspA is not protective against infection caused by serotype 19F in a mouse model.
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Prevalence of Various Vaccine Candidate Proteins in Clinical Isolates of Streptococcus pneumoniae: Characterization of the Novel Pht Fusion Proteins PhtA/B and PhtA/D. Pathogens 2019; 8:pathogens8040162. [PMID: 31554325 PMCID: PMC6963846 DOI: 10.3390/pathogens8040162] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/09/2019] [Accepted: 09/23/2019] [Indexed: 12/14/2022] Open
Abstract
Pneumococcal proteins unrelated to serotypes are considered to be candidates of antigens in next-generation vaccines. In the present study, the prevalence of vaccine candidate protein genes, along with serotypes and antimicrobial resistance determinants, was investigated in a total of 57 isolates obtained from a tertiary care hospital in Japan. All of the pediatric isolates and 76.6% of the adult isolates did not belong to PCV13 (a 13-valent pneumococcal conjugate vaccine) serotypes, and 70.2% of all isolates showed multidrug resistance. All of the isolates had ply, pavA, nanA, and nanB, and high prevalence was noted for the pspA and pspC genes (96.5% and 78.9%, respectively). Detection rates for the pneumococcal histidine triad protein (Pht) genes phtA, phtB, phtD, and phtE were 49.1%, 26.3%, 61.4%, and 100%, respectively. Two fusion-type genes, phtA/B and phtA/D, were identified, with a prevalence of 36.9% and 14.0%, respectively. These fusion types showed 78.1–90.0% nucleotide sequence identity with phtA, phtB, and phtD. The most prevalent pht profile was phtA + phtD + phtE (26.3%), followed by phtA/B + phtE (19.3%) and phtA/B + phtD + phtE (17.5%), while pht profiles including phtD and/or phtA/phtD were found in 71.9% of isolates. The present study revealed the presence of two fusion types of Pht and their unexpectedly high prevalence. These fusion types, as well as PhtA and PhtB, contained sequences similar to the B cell epitopes that have been previously reported for PhtD.
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Lagousi T, Basdeki P, Routsias J, Spoulou V. Novel Protein-Based Pneumococcal Vaccines: Assessing the Use of Distinct Protein Fragments Instead of Full-Length Proteins as Vaccine Antigens. Vaccines (Basel) 2019; 7:vaccines7010009. [PMID: 30669439 PMCID: PMC6466302 DOI: 10.3390/vaccines7010009] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 12/20/2022] Open
Abstract
Non-serotype-specific protein-based pneumococcal vaccines have received extensive research focus due to the limitations of polysaccharide-based vaccines. Pneumococcal proteins (PnPs), universally expressed among serotypes, may induce broader immune responses, stimulating humoral and cellular immunity, while being easier to manufacture and less expensive. Such an approach has raised issues mainly associated with sequence/level of expression variability, chemical instability, as well as possible undesirable reactogenicity and autoimmune properties. A step forward employs the identification of highly-conserved antigenic regions within PnPs with the potential to retain the benefits of protein antigens. Besides, their low-cost and stable construction facilitates the combination of several antigenic regions or peptides that may impair different stages of pneumococcal disease offering even wider serotype coverage and more efficient protection. This review discusses the up-to-date progress on PnPs that are currently under clinical evaluation and the challenges for their licensure. Focus is given on the progress on the identification of antigenic regions/peptides within PnPs and their evaluation as vaccine candidates, accessing their potential to overcome the issues associated with full-length protein antigens. Particular mention is given of the use of newer delivery system technologies including conjugation to Toll-like receptors (TLRs) and reformulation into nanoparticles to enhance the poor immunogenicity of such antigens.
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Affiliation(s)
- Theano Lagousi
- First Department of Paediatrics, "Aghia Sophia" Children's Hospital, Immunobiology Research Laboratory and Infectious Diseases Department "MAKKA," Athens Medical School, 11527 Athens, Greece.
| | - Paraskevi Basdeki
- First Department of Paediatrics, "Aghia Sophia" Children's Hospital, Immunobiology Research Laboratory and Infectious Diseases Department "MAKKA," Athens Medical School, 11527 Athens, Greece.
| | - John Routsias
- Department of Microbiology, Athens Medical School, 11527 Athens, Greece.
| | - Vana Spoulou
- First Department of Paediatrics, "Aghia Sophia" Children's Hospital, Immunobiology Research Laboratory and Infectious Diseases Department "MAKKA," Athens Medical School, 11527 Athens, Greece.
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12
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Xi H, Yu J, Sun Q, Lu J, Gu T, Guo X, Li B, Chen X, Zhang K, Kong W, Wu Y. Expression and purification of pneumococcal surface protein a of clade 4 in Escherichia coli using hydroxylapatite and ion-exchange column chromatography. Protein Expr Purif 2018; 151:56-61. [DOI: 10.1016/j.pep.2018.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/12/2018] [Accepted: 06/12/2018] [Indexed: 10/14/2022]
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13
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Mukerji R, Hendrickson C, Genschmer KR, Park SS, Bouchet V, Goldstein R, Lefkowitz EJ, Briles DE. The diversity of the proline-rich domain of pneumococcal surface protein A (PspA): Potential relevance to a broad-spectrum vaccine. Vaccine 2018; 36:6834-6843. [PMID: 30293761 DOI: 10.1016/j.vaccine.2018.08.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/18/2018] [Accepted: 08/19/2018] [Indexed: 01/28/2023]
Abstract
Pneumococcal surface protein A (PspA) is a surface exposed, highly immunogenic protein of Streptococcus pneumoniae. Its N-terminal α-helical domain (αHD) elicits protective antibody in humans and animals that can protect mice from fatal infections with pneumococci and can be detected in vitro with opsonophagocytosis assays. The proline-rich domain (PRD) in the center of the PspA sequence can also elicit protection. This study revealed that although the sequence of PRD was diverse, PRD from different pneumococcal isolates contained many shared elements. The inferred amino acid sequences of 123 such PRDs, which were analyzed by assembly and alignment-free (AAF) approaches, formed three PRD groups. Of these sequences, 45 were classified as Group 1, 19 were classified as Group 2, and 59 were classified as Group 3. All Group 3 sequences contained a highly conserved 22-amino acid non-proline block (NPB). A significant polymorphism was observed, however, at a single amino acid position within NPB. Each of the three PRD groups had characteristic patterns of short amino acid repeats, with most of the repeats being found in more than one PRD group. One of these repeats, PKPEQP as well as the NPB were previously shown to elicit protective antibodies in mice. In this study, we found that sera from 12 healthy human adult volunteers contained antibodies to all three PRD groups. This suggested that a PspA-containing vaccine containing carefully selected PRDs and αHDs could redundantly cover the known diversity of PspA. Such an approach might reduce the chances of PspA variants escaping a PspA vaccine's immunity.
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Affiliation(s)
- Reshmi Mukerji
- Department of Microbiology, University of Alabama at Birmingham, United States
| | - Curtis Hendrickson
- Center for Clinical and Translational Sciences, University of Alabama at Birmingham, United States
| | - Kristopher R Genschmer
- Department of Microbiology, University of Alabama at Birmingham, United States; Department of Medicine, Division of Pulmonary, Allergy and Critical Care, United States
| | - Sang-Sang Park
- Department of Microbiology, University of Alabama at Birmingham, United States
| | - Valérie Bouchet
- Section of Molecular Genetics, Maxwell Finland Laboratory for Infectious Diseases, Division of Pediatric Infectious Diseases, Boston University Medical Center, Boston, MA 02118, United States
| | - Richard Goldstein
- Section of Molecular Genetics, Maxwell Finland Laboratory for Infectious Diseases, Division of Pediatric Infectious Diseases, Boston University Medical Center, Boston, MA 02118, United States
| | - Elliot J Lefkowitz
- Department of Microbiology, University of Alabama at Birmingham, United States; Center for Clinical and Translational Sciences, University of Alabama at Birmingham, United States
| | - David E Briles
- Department of Microbiology, University of Alabama at Birmingham, United States.
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14
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Streptococcus pneumoniae PspC Subgroup Prevalence in Invasive Disease and Differences in Contribution to Complement Evasion. Infect Immun 2018; 86:IAI.00010-18. [PMID: 29378798 DOI: 10.1128/iai.00010-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 01/24/2018] [Indexed: 01/20/2023] Open
Abstract
The pneumococcal capsular serotype is an important determinant of complement resistance and invasive disease potential, but other virulence factors have also been found to contribute. Pneumococcal surface protein C (PspC), a highly variable virulence protein that binds complement factor H to evade C3 opsonization, is divided into two subgroups: choline-bound subgroup I and LPxTG-anchored subgroup II. The prevalence of different PspC subgroups in invasive pneumococcal disease (IPD) and functional differences in complement evasion are unknown. The prevalence of PspC subgroups in IPD isolates was determined in a collection of 349 sequenced strains of Streptococcus pneumoniae isolated from adult patients. pspC deletion mutants and isogenic pspC switch mutants were constructed to study differences in factor H binding and complement evasion in relation to capsule thickness. Subgroup I pspC was far more prevalent in IPD isolates than subgroup II pspC The presence of capsule was associated with a greater ability of bound factor H to reduce complement opsonization. Pneumococcal subgroup I PspC bound significantly more factor H and showed more effective complement evasion than subgroup II PspC in isogenic encapsulated pneumococci. We conclude that variation in the PspC subgroups, independent of capsule serotypes, affects pneumococcal factor H binding and its ability to evade complement deposition.
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15
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Antigenic Variation in Streptococcus pneumoniae PspC Promotes Immune Escape in the Presence of Variant-Specific Immunity. mBio 2018. [PMID: 29535198 PMCID: PMC5850329 DOI: 10.1128/mbio.00264-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Genomic analysis reveals extensive sequence variation and hot spots of recombination in surface proteins of Streptococcus pneumoniae. While this phenomenon is commonly attributed to diversifying selection by host immune responses, there is little mechanistic evidence for the hypothesis that diversification of surface protein antigens produces an immune escape benefit during infection with S. pneumoniae. Here, we investigate the biological significance of sequence variation within the S. pneumoniae cell wall-associated pneumococcal surface protein C (PspC) protein antigen. Using pspC allelic diversity observed in a large pneumococcal collection, we produced variant-specific protein constructs that span the sequence variability within the pspC locus. We show that antibodies raised against these PspC constructs are variant specific and prevent association between PspC and the complement pathway mediator, human factor H. We found that PspC variants differ in their capacity to bind factor H, suggesting that sequence variation within pspC reflects differences in biological function. Finally, in an antibody-dependent opsonophagocytic assay, S. pneumoniae expressing a PspC variant matching the antibody specificity was killed efficiently. In contrast, killing efficacy was not evident against S. pneumoniae expressing mismatched PspC variants. Our data suggest that antigenic variation within the PspC antigen promotes immune evasion and could confer a fitness benefit during infection. Loci encoding surface protein antigens in Streptococcus pneumoniae are highly polymorphic. It has become a truism that these polymorphisms are the outcome of selective pressure on S. pneumoniae to escape host immunity. However, there is little mechanistic evidence to support the hypothesis that diversifying protein antigens produces a benefit for the bacteria. Using the highly diverse pspC locus, we have now characterized the functional and immune implications of sequence diversity within the PspC protein. We have characterized the spectrum of biological function among diverse PspC variants and show that pspC sequence diversity reflects functional differences. Further, we show that sequence variation in PspC confers an immune escape benefit in the presence of anti-PspC variant-specific immunity. Overall, the results of our studies provide insights into the functional implications of protein sequence diversity and the role of variant-specific immunity in its maintenance.
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Yun KW, Choi EH, Lee HJ. Genetic diversity of pneumococcal surface protein A in invasive pneumococcal isolates from Korean children, 1991-2016. PLoS One 2017; 12:e0183968. [PMID: 29131872 PMCID: PMC5683564 DOI: 10.1371/journal.pone.0183968] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/15/2017] [Indexed: 12/02/2022] Open
Abstract
Pneumococcal surface protein A (PspA) is an important virulence factor of pneumococci and has been investigated as a primary component of a capsular serotype-independent pneumococcal vaccine. Thus, we sought to determine the genetic diversity of PspA to explore its potential as a vaccine candidate. Among the 190 invasive pneumococcal isolates collected from Korean children between 1991 and 2016, two (1.1%) isolates were found to have no pspA by multiple polymerase chain reactions. The full length pspA genes from 185 pneumococcal isolates were sequenced. The length of pspA varied, ranging from 1,719 to 2,301 base pairs with 55.7–100% nucleotide identity. Based on the sequences of the clade-defining regions, 68.7% and 49.7% were in PspA family 2 and clade 3/family 2, respectively. PspA clade types were correlated with genotypes using multilocus sequence typing and divided into several subclades based on diversity analysis of the N-terminal α-helical regions, which showed nucleotide sequence identities of 45.7–100% and amino acid sequence identities of 23.1–100%. Putative antigenicity plots were also diverse among individual clades and subclades. The differences in antigenicity patterns were concentrated within the N-terminal 120 amino acids. In conclusion, the N-terminal α-helical domain, which is known to be the major immunogenic portion of PspA, is genetically variable and should be further evaluated for antigenic differences and cross-reactivity between various PspA types from pneumococcal isolates.
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Affiliation(s)
- Ki Wook Yun
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.,Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Eun Hwa Choi
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.,Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Hoan Jong Lee
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.,Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
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Th17-Mediated Cross Protection against Pneumococcal Carriage by Vaccination with a Variable Antigen. Infect Immun 2017; 85:IAI.00281-17. [PMID: 28717032 DOI: 10.1128/iai.00281-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/06/2017] [Indexed: 12/22/2022] Open
Abstract
Serotype-specific protection against Streptococcus pneumoniae is an important limitation of the current polysaccharide-based vaccines. To prevent serotype replacement, reduce transmission, and limit the emergence of new variants, it is essential to induce broad protection and restrict pneumococcal colonization. In this study, we used a prototype vaccine formulation consisting of lipopolysaccharide (LPS)-detoxified outer membrane vesicles (OMVs) from Salmonella enterica serovar Typhimurium displaying the variable N terminus of PspA (α1α2) for intranasal vaccination, which induced strong Th17 immunity associated with a substantial reduction of pneumococcal colonization. Despite the variable nature of this protein, a common major histocompatibility complex class (MHC-II) epitope was identified, based on in silico prediction combined with ex vivo screening, and was essential for interleukin-17 A (IL-17A)-mediated cross-reactivity and associated with cross protection. Based on 1,352 PspA sequences derived from a pneumococcal carriage cohort, this OMV-based vaccine formulation containing a single α1α2 type was estimated to cover 19.1% of strains, illustrating the potential of Th17-mediated cross protection.
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Azarian T, Grant LR, Georgieva M, Hammitt LL, Reid R, Bentley SD, Goldblatt D, Santosham M, Weatherholtz R, Burbidge P, Goklish N, Thompson CM, Hanage WP, O'Brien KL, Lipsitch M. Association of Pneumococcal Protein Antigen Serology With Age and Antigenic Profile of Colonizing Isolates. J Infect Dis 2017; 215:713-722. [PMID: 28035010 DOI: 10.1093/infdis/jiw628] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/22/2016] [Indexed: 01/08/2023] Open
Abstract
Background Several Streptococcus pneumoniae proteins play a role in pathogenesis and are being investigated as vaccine targets. It is largely unknown whether naturally acquired antibodies reduce the risk of colonization with strains expressing a particular antigenic variant. Methods Serum immunoglobulin G (IgG) titers to 28 pneumococcal protein antigens were measured among 242 individuals aged <6 months-78 years in Native American communities between 2007 and 2009. Nasopharyngeal swabs were collected >- 30 days after serum collection, and the antigen variant in each pneumococcal isolate was determined using genomic data. We assessed the association between preexisting variant-specific antibody titers and subsequent carriage of pneumococcus expressing a particular antigen variant. Results Antibody titers often increased across pediatric groups before decreasing among adults. Individuals with low titers against group 3 pneumococcal surface protein C (PspC) variants were more likely to be colonized with pneumococci expressing those variants. For other antigens, variant-specific IgG titers do not predict colonization. Conclusion We observed an inverse association between variant-specific antibody concentration and homologous pneumococcal colonization for only 1 protein. Further assessment of antibody repertoires may elucidate the nature of antipneumococcal antibody-mediated mucosal immunity while informing vaccine development.
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Affiliation(s)
- Taj Azarian
- Center for Communicable Disease Dynamics, Department of Epidemiology, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
| | - Lindsay R Grant
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Maria Georgieva
- Center for Communicable Disease Dynamics, Department of Epidemiology, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
| | - Laura L Hammitt
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Raymond Reid
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | - David Goldblatt
- Immunobiology Section, Institute of Child Health, University College London, UK
| | - Mathuran Santosham
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Robert Weatherholtz
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Paula Burbidge
- Immunobiology Section, Institute of Child Health, University College London, UK
| | - Novalene Goklish
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Claudette M Thompson
- Center for Communicable Disease Dynamics, Department of Epidemiology, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
| | - William P Hanage
- Center for Communicable Disease Dynamics, Department of Epidemiology, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
| | - Kate L O'Brien
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
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Jang S, Kim G, Oh J, Lee S, Kim D, Kim KH, Kim YH, Rhee DK, Lee S. Molecular characterization of a single-chain antibody variable fragment (scFv) specific for PspA from Streptococcus pneumoniae. Biochem Biophys Res Commun 2016; 482:141-146. [PMID: 27845043 DOI: 10.1016/j.bbrc.2016.10.150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022]
Abstract
Streptococcus pneumoniae is a major infectious agent responsible for pneumonia, otitis media, sepsis and meningitis. Pneumococcal surface protein A (PspA) is a well-characterized virulence factor localized on the surface and a target for vaccine development. In this study, we screened a single-chain antibody variable fragment (scFv) using phage display from a human synthetic library to select a clone 2B11. Affinity (Kd) of 2B11 was measured to be 5 nM using biolayer interferometry. 2B11 exhibited a dose-dependent recognition of recombinant PspA with no cross-reactivity towards pneumococcal antigens. The epitope on PspA was defined to residues 231-242 by mutational analysis. Molecular docking analysis supported the experimentally determined epitope, suggesting that the helix spanning residues 231-242 can bind to 2B11 with residues in the CDR-H3 (complementarity determining region 3 in the heavy chain) actively participating in the molecular contacts. Comparison of 2B11 with a commercial PspA antibody revealed that 2B11 exhibited a better specificity towards recombinant PspA antigen. 2B11 was capable of detecting endogenous PspA from pneumococcal lysates with affinity similar to that of the commercial antibody. Our study provides a molecular tool for biosensors detecting pneumococcal diseases.
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Affiliation(s)
- ShinA Jang
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Gyuhee Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jihye Oh
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Seungyeop Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Dongho Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Kook-Han Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Yong Ho Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Dong-Kwon Rhee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Sangho Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea.
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Glennie S, Gritzfeld JF, Pennington SH, Garner-Jones M, Coombes N, Hopkins MJ, Vadesilho CF, Miyaji EN, Wang D, Wright AD, Collins AM, Gordon SB, Ferreira DM. Modulation of nasopharyngeal innate defenses by viral coinfection predisposes individuals to experimental pneumococcal carriage. Mucosal Immunol 2016; 9:56-67. [PMID: 25921341 PMCID: PMC4703943 DOI: 10.1038/mi.2015.35] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/13/2015] [Indexed: 02/04/2023]
Abstract
Increased nasopharyngeal colonization density has been associated with pneumonia. We used experimental human pneumococcal carriage to investigate whether upper respiratory tract viral infection predisposes individuals to carriage. A total of 101 healthy subjects were screened for respiratory virus before pneumococcal intranasal challenge. Virus was associated with increased odds of colonization (75% virus positive became colonized vs. 46% virus-negative subjects; P=0.02). Nasal Factor H (FH) levels were increased in virus-positive subjects and were associated with increased colonization density. Using an in vitro epithelial model we explored the impact of increased mucosal FH in the context of coinfection. Epithelial inflammation and FH binding resulted in increased pneumococcal adherence to the epithelium. Binding was partially blocked by antibodies targeting the FH-binding protein Pneumococcal surface protein C (PspC). PspC epitope mapping revealed individuals lacked antibodies against the FH binding region. We propose that FH binding to PspC in vivo masks this binding site, enabling FH to facilitate pneumococcal/epithelial attachment during viral infection despite the presence of anti-PspC antibodies. We propose that a PspC-based vaccine lacking binding to FH could reduce pneumococcal colonization, and may have enhanced protection in those with underlying viral infection.
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Affiliation(s)
- S Glennie
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.5337.20000 0004 1936 7603Present Address: 7Present address: School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK., ,
| | - J F Gritzfeld
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - S H Pennington
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - M Garner-Jones
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - N Coombes
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - M J Hopkins
- grid.269741.f0000 0004 0421 1585Liverpool Specialist Virology Centre, Royal Liverpool and Broadgreen University Hospital, Liverpool, UK
| | - C F Vadesilho
- grid.418514.d0000 0001 1702 8585Centro de Biotecnologia, Instituto Butantan, Sao Paulo, Brazil
| | - E N Miyaji
- grid.418514.d0000 0001 1702 8585Centro de Biotecnologia, Instituto Butantan, Sao Paulo, Brazil
| | - D Wang
- grid.48004.380000 0004 1936 9764Tropical Clinical Trial Unit, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A D Wright
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.269741.f0000 0004 0421 1585NIHR Royal Liverpool and Broadgreen University Hospital NHS Trust, Liverpool, UK
| | - A M Collins
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.269741.f0000 0004 0421 1585NIHR Royal Liverpool and Broadgreen University Hospital NHS Trust, Liverpool, UK
| | - S B Gordon
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - D M Ferreira
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
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