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Wang Y, Shi G, Wang X, Xie Z, Gou J, Huang L, Huang H, You W, Wang R, Yang Y, Wang F, Zhu T, Zhao D. Preliminary Evaluation of the Safety and Immunogenicity of a Novel Protein-Based Pneumococcal Vaccine in Healthy Adults Aged 18-49: A Phase Ia Randomized, Double Blind, Placebo-Controlled Clinical Study. Vaccines (Basel) 2024; 12:827. [PMID: 39203953 PMCID: PMC11358999 DOI: 10.3390/vaccines12080827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/11/2024] [Accepted: 07/13/2024] [Indexed: 09/03/2024] Open
Abstract
Background: Protein-based pneumococcal vaccines (PBPVs) may offer expanded protection against Streptococcus pneumoniae and tackle the antimicrobial resistance crisis in pneumococcal infections. This study examined the safety and immunogenicity in healthy adults vaccinated with three doses of a protein-based pneumococcal vaccine containing pneumococcal surface protein A (PspA) (PRX1, P3296 and P5668) and in combination with a recombinant detoxified pneumolysin protein (PlyLD). Methods: This phase Ia randomized, double blind, placebo-controlled clinical study enrolled healthy adults aged 18-49 years. The participants were randomized into experimental (low-dose, medium-dose, high-dose) and placebo groups in a ratio of 3:1. Three doses of investigational vaccine were given to the participants with an interval of two months. Safety endpoints included the occurrence of total adverse reactions, solicited local and systemic adverse reactions, unsolicited adverse reactions, serious adverse events (SAEs), and several laboratory parameters. Immunogenicity endpoints included geometric mean titers (GMT) of anti-PspA (PRX1, P3296 and P5668) and anti-PlyLD antibodies level as determined by ELISA, seropositivity rates of PspA and PlyLD antibodies (>4-fold increase) and neutralization activity of anti-Ply antibody in serum. Results: A total of 118 participants completed the study of three doses. The candidate PBPV was safe and well-tolerated in all experimental groups. No vaccine-related SAEs were observed in this study. Most solicited adverse reactions were mild and transient. The most frequently reported solicited adverse reactions in the medium- and high-dose groups was pain at the injection site, while in the low-dose group it was elevated blood pressure. The immunogenicity data showed a sharp increase in the GMT level of anti-PspA-RX1, anti-PspA-3296, anti-PspA-5668, and anti-PlyLD antibodies in serum. The results also showed that the elicited antibodies were dosage-dependent. The high-dose group showed a higher immune response against PspA-RX1, PspA-3296, PspA-5668, and PlyLD antigens. However, repeat vaccination did not increase the level of anti-PspA antibodies but the level of anti-PlyLD antibody. High seropositivity rates were also observed for anti-PspA-RX1, anti-PspA-3296, anti-PspA-5668, and anti-PlyLD antibodies. In addition, a significant difference in the GMT levels of anti-Ply antibody between the high-, medium-, and low-dose groups post each vaccination were indicated by neutralization activity tests. Conclusions: The PBPV showed a safe and immunogenic profile in this clinical trial. Taking into consideration both safety and immunogenicity data, we propose a single dose of 50 µg (medium dose) of PBPV as the optimum approach in providing expanded protection against Streptococcus pneumoniae.
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Affiliation(s)
- Yanxia Wang
- Henan Center for Disease Control and Prevention, Zhengzhou 450016, China; (Y.W.); (Z.X.); (L.H.); (W.Y.)
| | - Gang Shi
- National Institutes for Food and Drug Control, Beijing 100050, China;
| | - Xue Wang
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Zhiqiang Xie
- Henan Center for Disease Control and Prevention, Zhengzhou 450016, China; (Y.W.); (Z.X.); (L.H.); (W.Y.)
| | - Jinbo Gou
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Lili Huang
- Henan Center for Disease Control and Prevention, Zhengzhou 450016, China; (Y.W.); (Z.X.); (L.H.); (W.Y.)
| | - Haitao Huang
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Wangyang You
- Henan Center for Disease Control and Prevention, Zhengzhou 450016, China; (Y.W.); (Z.X.); (L.H.); (W.Y.)
| | - Ruijie Wang
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Yongli Yang
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou 450001, China;
| | - Feiyu Wang
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Tao Zhu
- CanSino Biologics Inc., Tianjin 300457, China; (X.W.); (J.G.); (H.H.); (R.W.); (F.W.)
| | - Dongyang Zhao
- Henan Center for Disease Control and Prevention, Zhengzhou 450016, China; (Y.W.); (Z.X.); (L.H.); (W.Y.)
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Vorobyev DS, Petukhova ES, Volokh YV, Semenova IB. Analysis of Immunobiological Properties of Recombinant Streptococcus pneumoniae Pneumolysin. Bull Exp Biol Med 2024; 177:248-251. [PMID: 39090461 DOI: 10.1007/s10517-024-06166-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Indexed: 08/04/2024]
Abstract
We compared the immunogenicity of recombinant S. pneumoniae pneumolysin (rPly) when administered with and without Al(OH)3 adjuvant, and evaluated the protective properties of recombinant protein in the active defense experiment. It was shown that double immunization with rPly+Al(OH)3 increases the levels of IgG antibodies in comparison with the control (p<0.01), while triple immunization results in a more significant increase in IgG antibody levels (p<0.001). Double immunization with rPly without Al(OH)3 does not induce a significant increase in antibody levels in comparison with the control, while triple immunization results in a slight but significant increase in antibody levels (p<0.05). The active defense test proved the protective activity of rPly against S. pneumoniae serotype 3 at intranasal infection.
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Affiliation(s)
- D S Vorobyev
- I. Mechnikov Research Institute of Vaccines and Sera, Moscow, Russia.
| | - E S Petukhova
- I. Mechnikov Research Institute of Vaccines and Sera, Moscow, Russia
| | - Yu V Volokh
- I. Mechnikov Research Institute of Vaccines and Sera, Moscow, Russia
| | - I B Semenova
- I. Mechnikov Research Institute of Vaccines and Sera, Moscow, Russia
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Wang R, Oliveira LVN, Hester MM, Carlson D, Christensen D, Specht CA, Levitz SM. Protection against experimental cryptococcosis elicited by Cationic Adjuvant Formulation 01-adjuvanted subunit vaccines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.24.591045. [PMID: 38712080 PMCID: PMC11071535 DOI: 10.1101/2024.04.24.591045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The fungal infection, cryptococcosis, is responsible for >100,000 deaths annually. No licensed vaccines are available. We explored the efficacy and immune responses of subunit cryptococcal vaccines adjuvanted with Cationic Adjuvant Formulation 01 (CAF01). CAF01 promotes humoral and T helper (Th) 1 and Th17 immune responses and has been safely used in human vaccine trials. Four subcutaneous vaccines, each containing single recombinant Cryptococcus neoformans protein antigens, partially protected mice from experimental cryptococcosis. Protection increased, up to 100%, in mice that received bivalent and quadrivalent vaccine formulations. Vaccinated mice that received a pulmonary challenge with C. neoformans had an influx of leukocytes into the lung including robust numbers of polyfunctional CD4+ T cells which produced Interferon gamma (IFNγ), tumor necrosis factor alpha (TNFα), and interleukin (IL)-17 upon ex vivo antigenic stimulation. Cytokine-producing lung CD8+ T cells were also found, albeit in lesser numbers. A significant, durable IFNγ response was observed in the lungs, spleen, and blood. Moreover, IFNγ secretion following ex vivo stimulation directly correlated with fungal clearance in the lungs. Thus, we have developed multivalent cryptococcal vaccines which protect mice from experimental cryptococcosis using an adjuvant which has been safely tested in humans. These preclinical studies suggest a path towards human cryptococcal vaccine trials.
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Affiliation(s)
- Ruiying Wang
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Lorena V. N. Oliveira
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Maureen M. Hester
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Diana Carlson
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Dennis Christensen
- Statens Serum Institut, Copenhagen, Denmark
- Present address: Croda Pharma, Diplomvej 381, Lyngby 2800, Denmark
| | - Charles A. Specht
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Stuart M. Levitz
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
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4
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Liu X, Van Maele L, Matarazzo L, Soulard D, Alves Duarte da Silva V, de Bakker V, Dénéréaz J, Bock FP, Taschner M, Ou J, Gruber S, Nizet V, Sirard JC, Veening JW. A conserved antigen induces respiratory Th17-mediated broad serotype protection against pneumococcal superinfection. Cell Host Microbe 2024; 32:304-314.e8. [PMID: 38417443 DOI: 10.1016/j.chom.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 12/06/2023] [Accepted: 02/05/2024] [Indexed: 03/01/2024]
Abstract
Several vaccines targeting bacterial pathogens show reduced efficacy upon concurrent viral infection, indicating that a new vaccinology approach is required. To identify antigens for the human pathogen Streptococcus pneumoniae that are effective following influenza infection, we performed CRISPRi-seq in a murine model of superinfection and identified the conserved lafB gene as crucial for virulence. We show that LafB is a membrane-associated, intracellular protein that catalyzes the formation of galactosyl-glucosyl-diacylglycerol, a glycolipid important for cell wall homeostasis. Respiratory vaccination with recombinant LafB, in contrast to subcutaneous vaccination, was highly protective against S. pneumoniae serotypes 2, 15A, and 24F in a murine model. In contrast to standard capsule-based vaccines, protection did not require LafB-specific antibodies but was dependent on airway CD4+ T helper 17 cells. Healthy human individuals can elicit LafB-specific immune responses, indicating LafB antigenicity in humans. Collectively, these findings present a universal pneumococcal vaccine antigen that remains effective following influenza infection.
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Affiliation(s)
- Xue Liu
- Department of Pathogen Biology, Base for International Science and Technology Cooperation, Carson Cancer Stem Cell Vaccines R&D Center, International Cancer Center, Shenzhen University Medical School, Shenzhen 518060, China; Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Laurye Van Maele
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, 59000 Lille, France
| | - Laura Matarazzo
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, 59000 Lille, France
| | - Daphnée Soulard
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, 59000 Lille, France
| | - Vinicius Alves Duarte da Silva
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, 59000 Lille, France
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Julien Dénéréaz
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Florian P Bock
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Michael Taschner
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Jinzhao Ou
- Department of Pathogen Biology, Base for International Science and Technology Cooperation, Carson Cancer Stem Cell Vaccines R&D Center, International Cancer Center, Shenzhen University Medical School, Shenzhen 518060, China
| | - Stephan Gruber
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Jean-Claude Sirard
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, 59000 Lille, France.
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland; Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
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Lane JR, Tata M, Yasmin R, Im H, Briles DE, Orihuela CJ. PspA-mediated aggregation protects Streptococcus pneumoniae against desiccation on fomites. mBio 2023; 14:e0263423. [PMID: 37982608 PMCID: PMC10746202 DOI: 10.1128/mbio.02634-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 10/10/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE Spn is a dangerous human pathogen capable of causing pneumonia and invasive disease. The virulence factor PspA has been studied for nearly four decades with well-established roles in pneumococcal evasion of C-reactive protein and neutralization of lactoferricin. Herein, we show that mammalian (m)GAPDH in mucosal secretions promotes aggregation of pneumococci in a PspA-dependent fashion, whereas lactoferrin counters this effect. PspA-mediated GAPDH-dependent bacterial aggregation protected Spn in nasal lavage elutes and grown in vitro from desiccation on fomites. Furthermore, surviving pneumococci within these aggregates retained their ability to colonize naïve hosts after desiccation. We report that Spn binds to and forms protein complexes on its surface composed of PspA, mGAPDH, and lactoferrin. Changes in the levels of these proteins therefore most likely have critical implications on Spn colonization, survival on fomites, and transmission.
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Affiliation(s)
- Jessica R. Lane
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Muralidhar Tata
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rahena Yasmin
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hansol Im
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David E. Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Carlos J. Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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6
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Lane JR, Tata M, Yasmin R, Im H, Briles DE, Orihuela CJ. PspA-mediated aggregation protects Streptococcus pneumoniae against desiccation on fomites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.27.559802. [PMID: 37808718 PMCID: PMC10557681 DOI: 10.1101/2023.09.27.559802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Streptococcus pneumoniae (Spn) resides in the nasopharynx where it can disseminate to cause disease. One key Spn virulence factor is pneumococcal surface protein A (PspA), which promotes survival by blocking the antimicrobial peptide lactoferricin. PspA has also been shown to mediate attachment to dying epithelial cells in the lower airway due to its binding of cell surface-bound mammalian (m)GAPDH. Importantly, the role of PspA during colonization is not well understood. Wildtype Spn was present in nasal lavage elutes collected from asymptomatically colonized mice at levels ~10-fold higher that its isogenic PspA-deficient mutant (ΔpspA). Wildtype Spn also formed aggregates in mucosal secretions composed of sloughed epithelial cells and hundreds of pneumococci, whereas ΔpspA did not. Spn within the center of these aggregates better survived prolonged desiccation on fomites than individual pneumococci and were capable of infecting naïve mice, indicating PspA-mediated aggregation conferred a survival/transmission advantage. Incubation of Spn in saline containing mGAPDH also enhanced tolerance to desiccation, but only for wildtype Spn. mGAPDH was sufficient to cause low-level aggregation of wildtype Spn but not ΔpspA. In strain WU2, the subdomain of PspA responsible for binding GAPDH (aa230-281) is ensconced within the lactoferrin (LF)-binding domain (aa167-288). We observed that LF inhibited GAPDH-mediated aggregation and desiccation tolerance. Using surface plasmon resonance, we determined that Spn forms multimeric complexes of PspA-GAPDH-LF on its surface and that LF dislodges GAPDH. Our findings have important implications regarding pneumococcal colonization/transmission processes and ongoing PspA-focused immunization efforts for this deadly pathogen.
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Affiliation(s)
- Jessica R. Lane
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Muralidhar Tata
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Rahena Yasmin
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Hansol Im
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - David E. Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Carlos J. Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
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Li S, Liang H, Zhao SH, Yang XY, Guo Z. Recent progress in pneumococcal protein vaccines. Front Immunol 2023; 14:1278346. [PMID: 37818378 PMCID: PMC10560988 DOI: 10.3389/fimmu.2023.1278346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/07/2023] [Indexed: 10/12/2023] Open
Abstract
Pneumococcal infections continue to pose a significant global health concern, necessitating the development of effective vaccines. Despite the progress shown by pneumococcal polysaccharide and conjugate vaccines, their limited coverage and the emergence of non-vaccine serotypes have highlighted the need for alternative approaches. Protein-based pneumococcal vaccines, targeting conserved surface proteins of Streptococcus pneumoniae, have emerged as a promising strategy. In this review, we provide an overview of the advancements made in the development of pneumococcal protein vaccines. We discuss the key protein vaccine candidates, highlight their vaccination results in animal studies, and explore the challenges and future directions in protein-based pneumococcal vaccine.
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Affiliation(s)
- Sha Li
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Hangeri Liang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Shui-Hao Zhao
- Center for Biological Science and Technology, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, Guangdong, China
| | - Xiao-Yan Yang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Zhong Guo
- Center for Biological Science and Technology, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, Guangdong, China
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Mbaezue RN, Okafor AT, Nkwocha BI, Ibeneme CN, Opara AC, Akahara DE, Okobi OE. The Effectiveness of Common Interventions in the Management of Sickle Cell Disease in Primary Care Settings: A Review. Cureus 2023; 15:e44780. [PMID: 37809245 PMCID: PMC10558056 DOI: 10.7759/cureus.44780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2023] [Indexed: 10/10/2023] Open
Abstract
Sickle cell disease (SCD), a chronic condition that affects men and women equally, continues to present a public health burden in the United States due to its associated morbidity and complications. Despite advances in medical knowledge and the design of novel therapies for managing the disease, its burden remains compounded because of increasing rates of immigration arising from global displacements and economic unrest in many countries. We thus conducted a comprehensive literature review of publications from 2000 to 2022 to gather guidelines on managing SCD, with a search through four databases, PubMed, Embase, Google Scholar, and Cochrane; 42 articles met the final inclusion criteria after the full-text article screening process. In the United States healthcare system, primary care physicians (PCPs) are generally providers who cater to the lifelong management of chronic medical conditions, SCD not being an exception. While more SCD patients now present to primary care clinics, many PCPs still lack the confidence and adequate experience necessary to manage the condition effectively. The gap created by the shortage of PCPs extensively equipped to provide comprehensive SCD care leads to poor health outcomes for patients. It is imperative now more than ever to continue to raise awareness about this condition at the provider level, to ensure that patients receive well-rounded care to improve their quality of life and clinical outcomes. Providing up-to-date knowledge about existing and novel therapies and/or modalities of SCD treatment would undoubtedly equip the PCPs with self-assurance to manage the condition adeptly. Thus, we explore various public health interventions such as hydroxyurea therapy, pneumococcal vaccination, penicillin therapy, iron chelation therapy, and clinical decision support tools that have been implemented in primary healthcare settings and shown to be effective in improving SCD care. We also discuss recent advancements that can lead to improved outcomes for SCD patients in the future.
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Affiliation(s)
- Rheiner N Mbaezue
- Health Services, Department of Health, Cape Town, ZAF
- Public Health, University of Limpopo, Polokwane, ZAF
| | - Adetoro T Okafor
- Epidemiology and Public Health, University of Minnesota School of Public Health, Minneapolis, USA
| | - Bernard I Nkwocha
- Internal Medicine, University of Utah College of Medicine, Salt Lake City, USA
| | | | - Amoge C Opara
- Medicine and Surgery, Biologic Delivery Technologies, Reno, USA
| | | | - Okelue E Okobi
- Family Medicine, Larkin Community Hospital Palm Springs Campus, Hialeah, USA
- Family Medicine, Medficient Health Systems, Laurel, USA
- Family Medicine, Lakeside Medical Center, Belle Glade, USA
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Afshari E, Ahangari Cohan R, Shams Nosrati MS, Mousavi SF. Development of a bivalent protein-based vaccine candidate against invasive pneumococcal diseases based on novel pneumococcal surface protein A in combination with pneumococcal histidine triad protein D. Front Immunol 2023; 14:1187773. [PMID: 37680628 PMCID: PMC10480505 DOI: 10.3389/fimmu.2023.1187773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 08/01/2023] [Indexed: 09/09/2023] Open
Abstract
Extensive efforts have been made toward improving effective strategies for pneumococcal vaccination, focusing on evaluating the potential of multivalent protein-based vaccines and overcoming the limitations of pneumococcal polysaccharide-based vaccines. In this study, we investigated the protective potential of mice co-immunization with the pneumococcal PhtD and novel rPspA proteins against pneumococcal sepsis infection. The formulations of each antigen alone or in combination were administered intraperitoneally with alum adjuvant into BALB/c mice three times at 14-day intervals. The production of antigen-specific IgG, IgG1 and IgG2a subclasses, and IL-4 and IFN-γ cytokines, were analyzed. Two in vitro complement- and opsonophagocytic-mediated killing activities of raised antibodies on day 42 were also assessed. Finally, the protection against an intraperitoneal challenge with 106 CFU/mouse of multi-drug resistance of Streptococcus pneumoniae ATCC49619 was investigated. Our findings showed a significant increase in the anti-PhtD and anti-rPspA sera IgG levels in the immunized group with the PhtD+rPspA formulation compared to each alone. Moreover, the results demonstrated a synergistic effect with a 6.7- and 1.3- fold increase in anti-PhtD and anti-rPspA IgG1, as well as a 5.59- and 1.08- fold increase in anti-PhtD and anti-rPspA IgG2a, respectively. Co-administration of rPspA+PhtD elicited a mixture of Th-2 and Th-1 immune responses, more towards Th-2. In addition, the highest complement-mediated killing activity was observed in the sera of the immunized group with PhtD+rPspA at 1/16 dilution, and the opsonophagocytic activity was increased from 74% to 86.3%. Finally, the survival rates showed that mice receiving the rPspA+PhtD formulation survived significantly longer (100%) than those receiving protein alone or PBS and exhibited the strongest clearance with a 2 log10 decrease in bacterial load in the blood 24h after challenge compared to the control group. In conclusion, the rPspA+PhtD formulation can be considered a promising bivalent serotype-independent vaccine candidate for protection against invasive pneumococcal infection in the future.
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Affiliation(s)
- Elnaz Afshari
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
- Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran
| | - Reza Ahangari Cohan
- Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran
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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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11
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Devarakonda Y, Reddy MVNJ, Neethu RS, Chandran A, Syal K. Multi epitope vaccine candidate design against Streptococcus pneumonia. J Biomol Struct Dyn 2023; 41:12654-12667. [PMID: 36636838 DOI: 10.1080/07391102.2023.2167123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 01/05/2023] [Indexed: 01/14/2023]
Abstract
Streptococcus pneumonia, the causative agent of sepsis, meningitis and pneumonia, is held responsible for causing invasive diseases predominantly in children along with adults from both developing and developed countries. The available vaccines coverage in the context of different serotypes is limited and emergence of non-vaccine serotypes could further emerge as a threat in future. Advanced immunoinformatics tools have been used for developing a multi epitope subunit vaccine. In the current study we have subjected these four surface antigenic proteins Ply, PsaA, PspA and PspK to construct vaccine designs. We have predicted different B-cell and T-cell epitopes by using NetCTL 1.2, IEDB (Immune Epitope Databases) and ABCpred. An adjuvant (griselimycin) has been added to the vaccine construct sequence in order to improve its immunogenicity. The vaccine construct has been evaluated for its antigenicity, allergenicity, toxicity and different physio-chemical properties. The bioinformatic tools have been used for prediction, refinement and validation of the 3 D structure. Further, the vaccine structure has been docked with a toll-like receptor (TLR-4) by ClusPro 2.0. In conclusion, the proposed multi-epitope vaccine designs could potentially activate both humoral and cellular immune responses and has a potential to be a vaccine candidate against S.pneumoniae, and requires experimental validation for ensuring immunogenicity and safety profile.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yogeshwar Devarakonda
- Department of Biological Sciences, Center for Genetics and Molecular Microbiology, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad, India
| | - M V N Janaradhan Reddy
- Department of Biological Sciences, Center for Genetics and Molecular Microbiology, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad, India
| | - R S Neethu
- Department of Biological Sciences, Center for Genetics and Molecular Microbiology, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad, India
| | - Aneesh Chandran
- Department of Biotechnology and Microbiology, Kannur University, Kannur, India
| | - Kirtimaan Syal
- Department of Biological Sciences, Center for Genetics and Molecular Microbiology, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad, India
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12
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Afshari E, Cohan RA, Sotoodehnejadnematalahi F, Mousavi SF. In-silico design and evaluation of an epitope-based serotype-independent promising vaccine candidate for highly cross-reactive regions of pneumococcal surface protein A. J Transl Med 2023; 21:13. [PMID: 36627666 PMCID: PMC9830136 DOI: 10.1186/s12967-022-03864-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/29/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The pathogenicity of pneumococcus with high morbidity, mortality, and multi-drug resistance patterns has been increasing. The limited coverage of the licensed polysaccharide-based vaccines and the replacement of the non-vaccine serotypes are the main reasons for producing a successful serotype-independent vaccine. Pneumococcal surface protein A (PspA) is an extremely important virulence factor and an interesting candidate for conserved protein-based pneumococcal vaccine classified into two prominent families containing five clades. PspA family-elicited immunity is clade-dependent, and the level of the PspA cross-reactivity is restricted to the same family. METHODS To cover and overcome the clade-dependent immunity of the PspAs in this study, we designed and tested a PspA1-5c+p vaccine candidate composed of the highest immunodominant coverage of B- and T-cell epitope truncated domain of each clade focusing on two cross-reactive B and C regions of the PspAs. The antigenicity, toxicity, physicochemical properties, 3D structure prediction, stability and flexibility of the designed protein using molecular dynamic (MD) simulation, molecular docking of the construct withHLADRB1*(01:01) and human lactoferrin N-lop, and immune simulation were assessed using immunoinformatics tools. In the experimental section, after intraperitoneal immunization of the mice with Alum adjuvanted recombinant PspA1-5c+p, we evaluated the immune response, cross-reactivity, and functionality of the Anti-PspA1-5c+p antibody using ELISA, Opsonophagocytic killing activity, and serum bactericidal assay. RESULTS For the first time, this work suggested a novel PspA-based vaccine candidate using immunoinformatics tools. The designed PspA1-5c+p protein is predicted to be highly antigenic, non-toxic, soluble, stable with low flexibility in MD simulation, and able to stimulate both humoral and cellular immune responses. The designed protein also could interact strongly with HLADRB1*(01:01) and human lactoferrin N-lop in the docking study. Our immunoinformatics predictions were validated using experimental data. Results showed that the anti-PspA1-5c+p IgG not only had a high titer with strong and same cross-reactivity coverage against all pneumococcal serotypes used but also had high and effective bioactivity for pneumococcal clearance using complement system and phagocytic cells. CONCLUSION Our findings elucidated the potential application of the PspA1-5c+p vaccine candidate as a serotype-independent pneumococcal vaccine with a strong cross-reactivity feature. Further in-vitro and in-vivo investigations against other PspA clades should be performed to confirm the full protection of the PspA1-5c+p vaccine candidate.
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Affiliation(s)
- Elnaz Afshari
- grid.411463.50000 0001 0706 2472Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Reza Ahangari Cohan
- grid.420169.80000 0000 9562 2611Department of Nanobiotechnology, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran
| | - Fattah Sotoodehnejadnematalahi
- grid.411463.50000 0001 0706 2472Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Seyed Fazlollah Mousavi
- grid.420169.80000 0000 9562 2611Department of Microbiology, Pasteur Institute of Iran, 69 Pasteur Ave., Tehran, 13164 Iran
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Musher DM, Anderson R, Feldman C. The remarkable history of pneumococcal vaccination: an ongoing challenge. Pneumonia (Nathan) 2022; 14:5. [PMID: 36153636 PMCID: PMC9509586 DOI: 10.1186/s41479-022-00097-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/22/2022] [Indexed: 11/21/2022] Open
Abstract
Although it varies with age and geographical distribution, the global burden of infection with Streptococcus pneumoniae (pneumococcus) remains considerable. The elderly, and younger adults with comorbid conditions, are at particularly high risk of pneumococcal infection, and this risk will increase as the population ages. Vaccination should be the backbone of our current strategies to deal with this infection. Main body: This manuscript reviews the history of the development of pneumococcal vaccines, and the impact of different vaccines and vaccination strategies over the past 111 years. It documents the early years of vaccine development in the gold mines of South Africa, when vaccination with killed pneumococci was shown to be effective, even before the recognition that different pneumococci were antigenically distinct. The development of type-specific vaccines, still with whole killed pneumococci, showed a high degree of efficacy. The identification of the importance of the pneumococcal capsule heralded the era of vaccination with capsular polysaccharides, although with the advent of penicillin, interest in pneumococcal vaccine development waned. The efforts of Austrian and his colleagues, who documented that despite penicillin therapy, patients still died from pneumococcal infection in the first 96 h, ultimately led to the licensing first of a 14-valent pneumococcal polysaccharide in 1977 followed by the 23-valent pneumococcal polysaccharide in 1983. The principal problem with these, as with other polysaccharide vaccines, was that that they failed to immunize infants and toddlers, who were at highest risk for pneumococcal disease. This was overcome by chemical linking or conjugation of the polysaccharide molecules to an immunogenic carrier protein. Thus began the era of pneumococcal conjugate vaccine (PCV), starting with PCV7, progressing to PCV10 and PCV13, and, most recently, PCV15 and PCV20. However, these vaccines remain serotype specific, posing the challenge of new serotypes replacing vaccine types. Current research addresses serotype-independent vaccines which, so far, has been a challenging and elusive endeavor. Conclusion: While there has been enormous progress in the development of pneumococcal vaccines during the past century, attempts to develop a vaccine that will retain its efficacy for most pneumococcal serotypes are ongoing.
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Mehanny M, Kroniger T, Koch M, Hoppstädter J, Becher D, Kiemer AK, Lehr C, Fuhrmann G. Yields and Immunomodulatory Effects of Pneumococcal Membrane Vesicles Differ with the Bacterial Growth Phase. Adv Healthc Mater 2022; 11:e2101151. [PMID: 34724354 DOI: 10.1002/adhm.202101151] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/22/2021] [Indexed: 12/20/2022]
Abstract
Streptococcus pneumoniae infections are a leading cause of death worldwide. Bacterial membrane vesicles (MVs) are promising vaccine candidates because of the antigenic components of their parent microorganisms. Pneumococcal MVs exhibit low toxicity towards several cell lines, but their clinical translation requires a high yield and strong immunogenic effects without compromising immune cell viability. MVs are isolated during either the stationary phase (24 h) or death phase (48 h), and their yields, immunogenicity and cytotoxicity in human primary macrophages and dendritic cells have been investigated. Death-phase vesicles showed higher yields than stationary-phase vesicles. Both vesicle types displayed acceptable compatibility with primary immune cells and several cell lines. Both vesicle types showed comparable uptake and enhanced release of the inflammatory cytokines, tumor necrosis factor and interleukin-6, from human primary immune cells. Proteomic analysis revealed similarities in vesicular immunogenic proteins such as pneumolysin, pneumococcal surface protein A, and IgA1 protease in both vesicle types, but stationary-phase MVs showed significantly lower autolysin levels than death-phase MVs. Although death-phase vesicles produced higher yields, they lacked superiority to stationary-phase vesicles as vaccine candidates owing to their similar antigenic protein cargo and comparable uptake into primary human immune cells.
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Affiliation(s)
- Mina Mehanny
- Helmholtz Institute for Pharmaceutical Research Saarland Biogenic Nanotherapeutics Group Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmacy Saarland University Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmaceutics and Industrial Pharmacy Faculty of Pharmacy Ain Shams University Cairo 11566 Egypt
| | - Tobias Kroniger
- Center for Functional Genomics of Microbes Department of Microbial Proteomics Institute of Microbiology University Greifswald Greifswald 17489 Germany
| | - Marcus Koch
- INM – Leibniz Institute for New Materials Campus D2.2 Saarbrücken 66123 Germany
| | - Jessica Hoppstädter
- Department of Pharmacy Pharmaceutical Biology Saarland University Saarbrücken 66123 Germany
| | - Dörte Becher
- Center for Functional Genomics of Microbes Department of Microbial Proteomics Institute of Microbiology University Greifswald Greifswald 17489 Germany
| | - Alexandra K. Kiemer
- Department of Pharmacy Pharmaceutical Biology Saarland University Saarbrücken 66123 Germany
| | - Claus‐Michael Lehr
- Department of Pharmacy Saarland University Campus E8.1 Saarbrücken 66123 Germany
- Helmholtz Institute for Pharmaceutical Research Saarland Drug Delivery Department Campus E8.1 Saarbrücken 66123 Germany
| | - Gregor Fuhrmann
- Helmholtz Institute for Pharmaceutical Research Saarland Biogenic Nanotherapeutics Group Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmacy Saarland University Campus E8.1 Saarbrücken 66123 Germany
- Friedrich‐Alexander‐University Erlangen‐Nürnberg Pharmaceutical Biology Department Biology Staudtstr. 5 Erlangen 91058 Germany
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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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Mungall BA, Hoet B, Nieto Guevara J, Soumahoro L. A systematic review of invasive pneumococcal disease vaccine failures and breakthrough with higher-valency pneumococcal conjugate vaccines in children. Expert Rev Vaccines 2021; 21:201-214. [PMID: 34882050 DOI: 10.1080/14760584.2022.2012455] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
INTRODUCTION : The pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV or PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13) protect against vaccine-serotype invasive pneumococcal disease (VT IPD). However, VT IPD can still occur in fully or partially vaccinated children (vaccine failure or breakthrough). We performed a systematic review of vaccine failures and breakthrough IPD with PCV10 and PCV13 in ≤5-year-olds. AREAS COVERED : We searched Scopus/Medline/EMBASE to retrieve articles/abstracts published between 1/2008-7/2019. We excluded reports from studies only including data from adults or children ≥6 years, exclusively assessing PCV7-vaccinated children or children with underlying comorbidities. Twenty-six reports (20 PCV13, 1 PCV10, 5 both), covering studies with various designs in six continents, using different schedules, were included. Collectively, these studies reported 469 VT IPD cases classified as vaccine failures and 403 as breakthrough. Vaccine failure and breakthrough rates were low: 8.4% and 9.3%, respectively, of all IPD in vaccinated children, consistent with the vaccines' high effectiveness. The main serotypes associated with vaccine failure or breakthrough were 19A, 3 and 19F in PCV13 studies and 14, 6B and vaccine-related 19A and 6A in PCV10 studies. EXPERT OPINION : As we move to vaccines with more serotypes, it is not only important to consider which serotypes are added, but also to monitor and address incomplete protection against specific serotypes.
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