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Araujo AP, Oliveira MLS, Miyaji EN. Negligible role for pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC) in the nasopharyngeal colonization of mice with a serotype 6B pneumococcal strain. Microb Pathog 2023; 185:106391. [PMID: 37839762 DOI: 10.1016/j.micpath.2023.106391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/15/2023] [Accepted: 10/12/2023] [Indexed: 10/17/2023]
Abstract
Streptococcus pneumoniae colonizes the human nasopharynx asymptomatically, but it can also cause several diseases, including otitis media, pneumonia, bacteremia, and meningitis. The colonization of the nasopharynx by the bacteria is an essential step for the pneumococcus to invade other sites and cause diseases. Pneumococcal surface protein A (PspA) and Pneumococcal surface Protein C (PspC) are important virulence factors and have been described to play roles in adhesion and immune evasion. In this study, we immunized mice subcutaneously with the recombinant α-helical region of PspA and/or PspC combined with different adjuvants to assess protection against colonization with the serotype 6B strain BHN418. Though high serum levels of specific IgG were detected, none of the formulations led to reduction in the colonization of the nasopharynx. The negative result may be due to the poor induction of IgG2c, which has been previously correlated with protection against pneumococcal colonization in mice. Furthermore, BHN418 pspA and pspC single and double knockouts were evaluated in colonization experiments and no differences in bacterial load were observed. In competition assays with the wild-type strain, borderline to no reduction was observed in the loads of the knockouts. Our results contrast with data from the literature using other pneumococcal strains, showing that the role of PspA and PspC in colonization can vary depending on the background of the knockout strain studied. BHN418 has been selected for its capacity to colonize humans in experimental challenge studies and may have redundant factors that compensate for the lack of PspA and PspC during nasopharyngeal colonization of mice.
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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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Lane JR, Tata M, Yasmin R, Im H, Briles DE, Orihuela CJ. PspA-mediated aggregation protects Streptococcus pneumoniae against desiccation on fomites. bioRxiv 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Huang X, Tan H, Lu F, Guo G, Han M, Cai T, Zhang H. Molecular characterization of invasive Streptococcus pneumoniae clinical isolates from a tertiary children's hospital in eastern China. Microbiol Spectr 2023; 11:e0091323. [PMID: 37754545 PMCID: PMC10580832 DOI: 10.1128/spectrum.00913-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 08/07/2023] [Indexed: 09/28/2023] Open
Abstract
Streptococcus pneumoniae is a common opportunistic pathogen that causes invasive pneumococcal disease (IPD), especially in children. This study aimed to determine the prevalence and molecular characteristics of S. pneumoniae isolated from children with IPD. A total of 78 S. pneumoniae isolates from aseptic body fluids of 70 IPD patients were collected at the Children's Hospital of Nanjing Medical University (Jiangsu Province, China) during 2017-2021. Whole-genome sequencing technology was used to analyze the serotype, sequence type (ST), virulence, and antibiotic resistance of the 78 invasive S. pneumoniae clinical isolates. Our results showed that the pneumococcal infection rate declined after the COVID-19 outbreak in 2019. Serotypes 19F, 14, 6A, 23F, 19A, and 6B were the most common strains. The pneumococcal conjugate vaccine (PCV) 13 serotype coverage rate was 87.1%. All isolates were classified by multi-locus sequence typing (MLST) analysis into 27 different STs, including 3 novel STs (ST17941, ST17942, and ST17944) and 1 novel allele [recP (558)]. The most predominant ST was ST271, followed by ST320 and ST876. All isolates carried the following virulence genes: cbpG, lytB, lytC, pce (cbpE), pavA, slrA, plr (gapA), hysA, nanA, eno, piuA, psaA, cppA, iga, htrA (degP), tig (ropA), zmpB, and ply. All isolates were multidrug resistant and had high levels of resistance to macrolides, tetracyclines, and sulfonamides. Taken together, this study revealed extensive genetic diversity among S. pneumoniae isolates from a single Chinese hospital. Wearing masks, universal infant vaccination with PCV13, and the launch of recombinant protein vaccine development programs could reduce the burden of IPD in children. IMPORTANCE Invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae in children remains a global burden and should be given more attention due to the fact that the pneumococcal vaccine is not fully covered globally. The molecular epidemiological characteristics of S. pneumoniae are not so clear, especially in these years of COVID-19. In this study, we collected S. pneumoniae isolates from the aseptic body fluid of children with IPD from 2017 to 2021 in a tertiary children's hospital in China and revealed the extensive genetic diversity of these isolates. Most importantly, we first found that the rate of pneumococcal infection has declined since the COVID-19 outbreak in 2019, which means that wearing masks could reduce the transmission of S. pneumoniae. In addition, it was shown that universal infant vaccination with PCV13 seems essential for reducing the burden of IPD in children.
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Affiliation(s)
- Xu Huang
- Department of Clinical Laboratory, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Hua Tan
- Department of Clinical Laboratory, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Feng Lu
- School of Mechanical Engineering, Tongji University, Shanghai, China
| | - Genglin Guo
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Mingxiao Han
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Tongbo Cai
- College of Computer and Information Engineering, Henan Normal University, Xinxiang, China
| | - Haifang Zhang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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See KC. Pneumococcal Vaccination in Adults: A Narrative Review of Considerations for Individualized Decision-Making. Vaccines (Basel) 2023; 11:vaccines11050908. [PMID: 37243012 DOI: 10.3390/vaccines11050908] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Pneumococcal disease remains one of the major causes of severe disease in both children and adults. Severe disease may be prevented by pneumococcal polysaccharide and conjugate vaccines, which currently cover more than 20 serotypes. However, unlike routine pneumococcal vaccination in children, guidelines promote only limited pneumococcal vaccination in adults, and do not cater for decision-making for individual patients. In this narrative review, considerations for individualized decision-making are identified and discussed. This review identifies and discusses considerations for individualized decision-making, including the risk of severe disease, immunogenicity, clinical efficacy, mucosal immunity, herd immunity, concomitant administration with other vaccines, waning immunity, and replacement strains.
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Affiliation(s)
- Kay Choong See
- Department of Medicine, National University Hospital, Singapore 119228, Singapore
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Thompson CD, Bradshaw JL, Miller WS, Vidal AGJ, Vidal JE, Rosch JW, McDaniel LS, Keller LE. Oligopeptide Transporters of Nonencapsulated Streptococcus pneumoniae Regulate CbpAC and PspA Expression and Reduce Complement-Mediated Clearance. mBio 2023; 14:e0332522. [PMID: 36625598 DOI: 10.1128/mbio.03325-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Streptococcus pneumoniae colonizes the human nasopharynx and causes several diseases. Pneumococcal vaccines target the polysaccharide capsule and prevent most serious disease, but there has been an increase in the prevalence of nonencapsulated S. pneumoniae (NESp). Previously, it was thought that a capsule was necessary to cause invasive disease. NESp strains expressing the oligopeptide transporters AliC and AliD have been isolated from patients with invasive disease. The AliC and AliD oligopeptide transporters regulate the expression of several genes, including choline binding protein AC (CbpAC) (a homolog of PspA), which aids in reducing C3b deposition. It is hypothesized that by altering CbpAC expression, AliC and AliD provide protection from classical complement-mediated clearance by reducing C-reactive protein (CRP) binding. Our study demonstrates that AliC and AliD regulate CbpAC expression in NESp and that AliD found in certain serotypes of encapsulated strains regulates PspA expression. C3b deposition was increased in the NESp ΔaliD and encapsulated mutants in comparison to the wild type. NESp strains expressing AliC and AliD have a significant decrease in C1q and CRP deposition in comparison to the ΔaliC ΔaliD mutant. The complement protein C1q is required for NESp clearance in a murine model and increases opsonophagocytosis. By regulating CbpAC expression, NESp inhibits CRP binding to the bacterial surface and blocks classical complement activation, leading to greater systemic survival and virulence. Due to the increase in the prevalence of NESp, it is important to gain a better understanding of NESp virulence mechanisms that aid in establishing disease and persistence within a host by avoiding clearance by the immune system. IMPORTANCE Streptococcus pneumoniae (pneumococcus) can cause a range of diseases. Although there is a robust pneumococcal vaccination program that reduces invasive pneumococcal disease by targeting various polysaccharide capsules, there has been an increase in the isolation of nonvaccine serotypes and nonencapsulated S. pneumoniae (NESp) strains. While most studies of pneumococcal pathogenesis have focused on encapsulated strains, there is little understanding of how NESp causes disease. NESp lacks a protective capsule but contains novel genes, such as aliC and aliD, which have been shown to regulate the expression of numerous genes and to be required for NESp virulence and immune evasion. Furthermore, NESp strains have high transformation efficiencies and harbor resistance to multiple drugs. This could be deleterious to current treatment strategies employed for pneumococcal disease as NESp can be a reservoir of drug resistance genes. Therefore, deciphering how NESp survives within a host and facilitates disease is a necessity that will allow the fabrication of improved, broad-spectrum treatments and preventatives against pneumococcal disease. Our study provides a better understanding of NESp virulence mechanisms during host-pathogen interactions through the examination of genes directly regulated by the NESp proteins AliC and AliD.
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Zhang Y, Jen FEC, Fox KL, Edwards JL, Jennings MP. The biosynthesis and role of phosphorylcholine in pathogenic and nonpathogenic bacteria. Trends Microbiol 2023:S0966-842X(23)00024-0. [PMID: 36863982 DOI: 10.1016/j.tim.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 03/03/2023]
Abstract
Phosphorylcholine (ChoP) can be found in all life forms. Although this molecule was first thought to be uncommon in bacteria, it is now appreciated that many bacteria express ChoP on their surface. ChoP is usually attached to a glycan structure, but in some cases, it is added as a post-translational modification to proteins. Recent findings have demonstrated the role of ChoP modification and phase variation (ON/OFF switching) in bacterial pathogenesis. However, the mechanisms of ChoP synthesis are still unclear in some bacteria. Here, we review the literature and examine the recent developments in ChoP-modified proteins and glycolipids and of ChoP biosynthetic pathways. We discuss how the well-studied Lic1 pathway exclusively mediates ChoP attachment to glycans but not to proteins. Finally, we provide a review of the role of ChoP in bacterial pathobiology and the role of ChoP in modulating the immune response.
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Affiliation(s)
- Yuan Zhang
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD 4222, Australia
| | - Freda E-C Jen
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD 4222, Australia
| | - Kate L Fox
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Jennifer L Edwards
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD 4222, Australia.
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Kono M, Iyo T, Murakami D, Sakatani H, Nanushaj D, Hotomi M. Maternal immunization with pneumococcal surface protein A provides the immune memories of offspring against pneumococcal infection. Front Cell Infect Microbiol 2023; 13:1059603. [PMID: 37033488 PMCID: PMC10076723 DOI: 10.3389/fcimb.2023.1059603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 02/28/2023] [Indexed: 04/11/2023] Open
Abstract
Introduction Streptococcus pneumoniae (S. pneumoniae) is one of the most widespread pathogens in the world and one of the largest infectious causes of infant mortality. Although current vaccines have various benefits, antibiotic resistance and the inability to vaccinate infants less than one year old demands the development of new protective strategies. One strategy, 'maternal immunization', is to protect infants by passive immunity from an immunized mother, although its mechanism is still not fully understood. Materials and methods The current study aimed to acquire immunity against S. pneumoniae in infants by maternal immunization with pneumococcal common antigen, pneumococcal surface protein A (PspA). Four-week-old female mice were immunized with recombinant PspA intranasally twice a week for three weeks. Females were mated with age-matched males after immunization, and delivered offspring. Results The week-old offspring derived from and fostered by immunized mothers had more anti-PspA-specific antibody producing cells in the spleen than those derived from sham-immunized mothers. The offspring were raised up to four weeks old and were subcutaneously stimulated with recombinant PspA. The levels of anti-PspA IgG in sera after stimulation were significantly higher in the offspring derived from the immunized mothers and the induced specific antibody to PspA showed protective efficacy against systemic pneumococcal infection. Discussion Maternal immunization is suggested to be able to provide a sustained immune memory to offspring. The current study would be a milestone in the field of maternal immunization toward a universal pneumococcal vaccine.
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Affiliation(s)
- Masamitsu Kono
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
| | - Takuro Iyo
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
- Department of Otorhinolaryngology-Head and Neck Surgery, Kinan Hospital, Tanabe, Japan
| | - Daichi Murakami
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
- Department of Otorhinolaryngology-Head and Neck Surgery, Kinan Hospital, Tanabe, Japan
| | - Hideki Sakatani
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
| | - Denisa Nanushaj
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
| | - Muneki Hotomi
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
- *Correspondence: Muneki Hotomi,
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11
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Aceil J, Avci FY. Pneumococcal Surface Proteins as Virulence Factors, Immunogens, and Conserved Vaccine Targets. Front Cell Infect Microbiol 2022; 12:832254. [PMID: 35646747 PMCID: PMC9133333 DOI: 10.3389/fcimb.2022.832254] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic pathogen that causes over 1 million deaths annually despite the availability of several multivalent pneumococcal conjugate vaccines (PCVs). Due to the limitations surrounding PCVs along with an evolutionary rise in antibiotic-resistant and unencapsulated strains, conserved immunogenic proteins as vaccine targets continue to be an important field of study for pneumococcal disease prevention. In this review, we provide an overview of multiple classes of conserved surface proteins that have been studied for their contribution to pneumococcal virulence. Furthermore, we discuss the immune responses observed in response to these proteins and their promise as vaccine targets.
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