Improving vaccines against Streptococcus pneumoniae using synthetic glycans

Streptococcus pneumoniae remains a deadly disease in small children and the elderly even though conjugate and polysaccharide vaccines based on isolated capsular polysaccharides (CPS) are successful. The most common serotypes that cause infection are used in vaccines around the world, but differences in geographic and demographic serotype distribution compromises protection by leading vaccines. The medicinal chemistry approach to glycoconjugate vaccine development has helped to improve the stability and immunogenicity of synthetic vaccine candidates for several serotypes leading to the induction of higher levels of specific protective antibodies. Here, we show that marketed CPS-based glycoconjugate vaccines can be improved by adding synthetic glycoconjugates representing serotypes that are not covered by existing vaccines. Combination (coformulation) of synthetic glycoconjugates with the licensed vaccines Prevnar13 (13-valent) and Synflorix (10-valent) yields improved 15- and 13-valent conjugate vaccines, respectively, in rabbits. A pentavalent semisynthetic glycoconjugate vaccine containing five serotype antigens (sPCV5) elicits antibodies with strong in vitro opsonophagocytic activity. This study illustrates that synthetic oligosaccharides can be used in coformulation with both isolated polysaccharide glycoconjugates to expand protection from existing vaccines and each other to produce precisely defined multivalent conjugated vaccines.

Download Full-text

Biomineralization improves the stability of a Streptococcus pneumoniae protein vaccine at high temperatures

Nanomedicine ◽

10.2217/nnm-2021-0023 ◽

2021 ◽

Author(s):

Yajun Min ◽

Wenchun Xu ◽

Yunju Xiao ◽

Jiangming Xiao ◽

Zhaoche Shu ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

High Temperatures ◽

Vaccine Development ◽

Effective Means ◽

Proteinase K ◽

Protein Vaccine ◽

Protein Vaccines ◽

The Stability

Aim: Protein vaccines have been the focus of research for vaccine development due to their safety record and facile production. Improving the stability of proteins is of great significance to the application of protein vaccines. Materials & methods: Based on the proteins pneumolysin and DnaJ of Streptococcus pneumoniae, biomineralization was carried out to prepare protein nanoparticles, and their thermal stability was tested both in vivo and in vitro. Results: Mineralized nanoparticles were formed successfully and these calcium phosphate-encapsulated proteins were resistant to proteinase K degradation and were thermally stable at high temperatures. The mineralized proteins retained the immunoreactivity of the original proteins. Conclusion: Mineralization technology is an effective means to stabilize protein vaccines, presenting a safe and economical method for vaccine administration.

Download Full-text

Recent and Future Advances in the Chemoenzymatic Synthesis of Homogeneous Glycans for Bacterial Glycoconjugate Vaccine Development

Vaccines ◽

10.3390/vaccines9091021 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1021

Author(s):

Ayobami Adegbite ◽

Pumtiwitt C. McCarthy

Keyword(s):

Immune Response ◽

Vaccine Development ◽

Disease Outbreaks ◽

Chemoenzymatic Synthesis ◽

Conjugate Vaccines ◽

Oligosaccharide Chain ◽

Glycoconjugate Vaccines ◽

Glycoconjugate Vaccine ◽

The Relationship ◽

Number Of Bacteria

Vaccines are important in preventing disease outbreaks and controlling the spread of disease in a population. A variety of vaccines exist, including subunit, recombinant, and conjugate vaccines. Glycoconjugate vaccines have been an important tool to fight against diseases caused by a number of bacteria. Glycoconjugate vaccines are often heterogeneous. Vaccines of the future are becoming more rationally designed to have a defined oligosaccharide chain length and position of conjugation. Homogenous vaccines could play an important role in assessing the relationship between vaccine structure and immune response. This review focuses on recent advances in the chemoenzymatic production of defined bacterial oligosaccharides for vaccine development with a focus on Neisseria meningitidis and selected WHO-prioritized antibacterial resistant-pathogens. We also provide some perspective on future advances in the chemoenzymatic synthesis of well-defined oligosaccharides.

Download Full-text

Synthesis and delivery of Streptococcus pneumoniae capsular polysaccharides by recombinant attenuated Salmonella vaccines

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2013350118 ◽

2020 ◽

Vol 118 (2) ◽

pp. e2013350118

Author(s):

Huali Su ◽

Qing Liu ◽

Xiaoping Bian ◽

Shifeng Wang ◽

Roy Curtiss ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Vaccine Development ◽

Low Cost ◽

Developed Countries ◽

Oral Immunization ◽

Capsular Polysaccharides ◽

Pneumococcal Infections ◽

Innovative Strategy ◽

Main Components

Streptococcus pneumoniae capsular polysaccharides (CPSs) are major determinants of bacterial pathogenicity. CPSs of different serotypes form the main components of the pneumococcal vaccines Pneumovax, Prevnar7, and Prevnar13, which substantially reduced the S. pneumoniae disease burden in developed countries. However, the laborious production processes of traditional polysaccharide-based vaccines have raised the cost of the vaccines and limited their impact in developing countries. The aim of this study is to develop a kind of low-cost live vaccine based on using the recombinant attenuated Salmonella vaccine (RASV) system to protect against pneumococcal infections. We cloned genes for seven different serotypes of CPSs to be expressed by the RASV strain. Oral immunization of mice with the RASV-CPS strains elicited robust Th1 biased adaptive immune responses. All the CPS-specific antisera mediated opsonophagocytic killing of the corresponding serotype of S. pneumoniae in vitro. The RASV-CPS2 and RASV-CPS3 strains provided efficient protection of mice against challenge infections with either S. pneumoniae strain D39 or WU2. Synthesis and delivery of S. pneumoniae CPSs using the RASV strains provide an innovative strategy for low-cost pneumococcal vaccine development, production, and use.

Download Full-text

A semisynthetic glycoconjugate provides expanded cross-serotype protection against Streptococcus pneumoniae

10.1101/2021.07.29.454378 ◽

2021 ◽

Author(s):

Paulina M Kaplonek ◽

Ling Yao ◽

Katrin Reppe ◽

Franziska M Voss ◽

Thomas Kohler ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Bacterial Load ◽

Large Animal Model ◽

Pneumococcal Vaccines ◽

Large Animal ◽

Proof Of Concept ◽

Additional Protection ◽

Synthetic Oligosaccharides ◽

Glycoconjugate Vaccine ◽

Reduce Disease Severity

Streptococcus pneumoniae infections are the leading cause of child mortality globally. Current vaccines fail to induce a protective immune response towards a conserved part of the pathogen, resulting in new serotypes causing disease. Therefore, new vaccine strategies are urgently needed. Described is a two-pronged approach combining S.pneumoniae proteins, pneumolysin and PspA, with a precisely defined synthetic oligosaccharide, whereby the carrier protein acts as a serotype-independent antigen to provide additional protection. Proof of concept in mice and swine models revealed that the conjugates inhibit colonization of the nasopharynx, decrease the bacterial load and reduce disease severity in the bacteria challenged model. Immunization of piglets provided the first evidence for the immunogenicity and protective potential of synthetic glycoconjugate vaccine in a large animal model. A combination of synthetic oligosaccharides with proteins from the target pathogen opens the path to create broadly cross-protective ("universal") pneumococcal vaccines.

Download Full-text

Fluorocycline TP-271 Is Potent against Complicated Community-Acquired Bacterial Pneumonia Pathogens

mSphere ◽

10.1128/msphere.00004-17 ◽

2017 ◽

Vol 2 (1) ◽

Cited By ~ 14

Author(s):

Trudy H. Grossman ◽

Corey Fyfe ◽

William O’Brien ◽

Meredith Hackel ◽

Mary Beth Minyard ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Streptococcus Pneumoniae ◽

Bacterial Pneumonia ◽

The Elderly ◽

Multidrug Resistant ◽

New Antibiotics ◽

Severe Infections ◽

Intravenous And Oral Administration ◽

Resistance Rates

ABSTRACT Rising resistance rates for macrolides, fluoroquinolones, and β-lactams in the most common pathogens associated with community-acquired bacterial pneumonia (CABP) are of concern, especially for cases of moderate to severe infections in vulnerable populations such as the very young and the elderly. New antibiotics that are active against multidrug-resistant Streptococcus pneumoniae and Staphylococcus aureus are needed for use in the empirical treatment of the most severe forms of this disease. TP-271 is a promising new fluorocycline antibiotic demonstrating in vitro potency and nonclinical efficacy by intravenous and oral administration against the major pathogens associated with moderate to severe CABP. TP-271 is a novel, fully synthetic fluorocycline antibiotic in clinical development for the treatment of respiratory infections caused by susceptible and multidrug-resistant pathogens. TP-271 was active in MIC assays against key community respiratory Gram-positive and Gram-negative pathogens, including Streptococcus pneumoniae (MIC90 = 0.03 µg/ml), methicillin-sensitive Staphylococcus aureus (MSSA; MIC90 = 0.25 µg/ml), methicillin-resistant S. aureus (MRSA; MIC90 = 0.12 µg/ml), Streptococcus pyogenes (MIC90 = 0.03 µg/ml), Haemophilus influenzae (MIC90 = 0.12 µg/ml), and Moraxella catarrhalis (MIC90 ≤0.016 µg/ml). TP-271 showed activity (MIC90 = 0.12 µg/ml) against community-acquired MRSA expressing Panton-Valentine leukocidin (PVL). MIC90 values against Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae were 0.004, 1, and 4 µg/ml, respectively. TP-271 was efficacious in neutropenic and immunocompetent animal pneumonia models, generally showing, compared to the burden at the start of dosing, ~2 to 5 log10 CFU reductions against MRSA, S. pneumoniae, and H. influenzae infections when given intravenously (i.v.) and ~1 to 4 log10 CFU reductions when given orally (p.o.). TP-271 was potent against key community-acquired bacterial pneumonia (CABP) pathogens and was minimally affected, or unaffected, by tetracycline-specific resistance mechanisms and fluoroquinolone or macrolide drug resistance phenotypes. IMPORTANCE Rising resistance rates for macrolides, fluoroquinolones, and β-lactams in the most common pathogens associated with community-acquired bacterial pneumonia (CABP) are of concern, especially for cases of moderate to severe infections in vulnerable populations such as the very young and the elderly. New antibiotics that are active against multidrug-resistant Streptococcus pneumoniae and Staphylococcus aureus are needed for use in the empirical treatment of the most severe forms of this disease. TP-271 is a promising new fluorocycline antibiotic demonstrating in vitro potency and nonclinical efficacy by intravenous and oral administration against the major pathogens associated with moderate to severe CABP.

Download Full-text

Control of Streptococcal Infections: Is a Common Vaccine Target Achievable Against Streptococcus agalactiae and Streptococcus pneumoniae

Frontiers in Microbiology ◽

10.3389/fmicb.2021.658824 ◽

2021 ◽

Vol 12 ◽

Author(s):

Edmund Bedeley ◽

Andrea Gori ◽

Dorothy Yeboah-Manu ◽

Kanny Diallo

Keyword(s):

Streptococcus Pneumoniae ◽

Streptococcus Agalactiae ◽

Vaccine Development ◽

Genomic Sequence ◽

Group B Streptococcus ◽

The Elderly ◽

Pneumococcal Infections ◽

Antibiotics Use ◽

Life Threatening ◽

Group B

Both Streptococcus agalactiae [group B streptococcus (GBS)] and Streptococcus pneumoniae (pneumococcus) remain significant pathogens as they cause life threatening infections mostly in children and the elderly. The control of diseases caused by these pathogens is dependent on antibiotics use and appropriate vaccination. The introduction of the pneumococcal conjugate vaccines (PCVs) against some serotypes has led to reduction in pneumococcal infections, however, the subsequent serotype switching, and replacement has been a serious challenge. On the other hand, no vaccine is yet licensed for use in the control of GBS diseases. In this review, we provide an overview of the history and global disease burden, disease pathophysiology and management, vaccines update, and the biology of both pathogens. Furthermore, we address recent findings regarding structural similarities that could be explored for vaccine targets across both mucosal pathogens. Finally, we conclude by proposing future genomic sequence comparison using the wealth of available sequences from both species and the possibility of identifying more related structural components that could be exploited for pan-pathogen vaccine development.

Download Full-text

Corynebacterium Species Inhibit Streptococcus pneumoniae Colonization and Infection of the Mouse Airway

Frontiers in Microbiology ◽

10.3389/fmicb.2021.804935 ◽

2022 ◽

Vol 12 ◽

Author(s):

Kadi J. Horn ◽

Alexander C. Jaberi Vivar ◽

Vera Arenas ◽

Sameer Andani ◽

Edward N. Janoff ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Respiratory Health ◽

Upper Airway ◽

Inhibitory Effect ◽

Airway Microbiome ◽

The Stability ◽

Independent Effects ◽

The Impact

The stability and composition of the airway microbiome is an important determinant of respiratory health. Some airway bacteria are considered to be beneficial due to their potential to impede the acquisition and persistence of opportunistic bacterial pathogens such as Streptococcus pneumoniae. Among such organisms, the presence of Corynebacterium species correlates with reduced S. pneumoniae in both adults and children, in whom Corynebacterium abundance is predictive of S. pneumoniae infection risk. Previously, Corynebacterium accolens was shown to express a lipase which cleaves host lipids, resulting in the production of fatty acids that inhibit growth of S. pneumoniae in vitro. However, it was unclear whether this mechanism contributes to Corynebacterium-S. pneumoniae interactions in vivo. To address this question, we developed a mouse model for Corynebacterium colonization in which colonization with either C. accolens or another species, Corynebacterium amycolatum, significantly reduced S. pneumoniae acquisition in the upper airway and infection in the lung. Moreover, the lungs of co-infected mice had reduced pro-inflammatory cytokines and inflammatory myeloid cells, indicating resolution of infection-associated inflammation. The inhibitory effect of C. accolens on S. pneumoniae in vivo was mediated by lipase-dependent and independent effects, indicating that both this and other bacterial factors contribute to Corynebacterium-mediated protection in the airway. We also identified a previously uncharacterized bacterial lipase in C. amycolatum that is required for inhibition of S. pneumoniae growth in vitro. Together, these findings demonstrate the protective potential of airway Corynebacterium species and establish a new model for investigating the impact of commensal microbiota, such as Corynebacterium, on maintaining respiratory health.

Download Full-text

A Capsular Polysaccharide-Specific Antibody Alters Streptococcus pneumoniae Gene Expression during Nasopharyngeal Colonization of Mice

Infection and Immunity ◽

10.1128/iai.00300-18 ◽

2018 ◽

Vol 86 (7) ◽

Cited By ~ 6

Author(s):

Christopher R. Doyle ◽

Jee-Young Moon ◽

Johanna P. Daily ◽

Tao Wang ◽

Liise-anne Pirofski

Keyword(s):

Oxidative Stress ◽

Gene Expression ◽

Streptococcus Pneumoniae ◽

Capsular Polysaccharide ◽

Vaccine Development ◽

Lavage Fluid ◽

Uptake System ◽

Content Type

ABSTRACT Pneumococcal conjugate vaccines (PCV) elicit opsonophagocytic (opsonic) antibodies to pneumococcal capsular polysaccharides (PPS) and reduce nasopharyngeal (NP) colonization by vaccine-included Streptococcus pneumoniae serotypes. However, nonopsonic antibodies may also be important for protection against pneumococcal disease. For example, 1E2, a mouse IgG1 monoclonal antibody (MAb) to the serotype 3 (ST3) PPS (PPS3), reduced ST3 NP colonization in mice and altered ST3 gene expression in vitro . Here, we determined whether 1E2 affects ST3 gene expression in vivo during colonization of mice by performing RNA sequencing on NP lavage fluid from ST3-infected mice treated with 1E2, a control MAb, or phosphate-buffered saline. Compared to the results for the controls, 1E2 significantly altered the expression of over 50 genes. It increased the expression of the piuBCDA operon, which encodes an iron uptake system, and decreased the expression of dpr , which encodes a protein critical for resistance to oxidative stress. 1E2-mediated effects on ST3 in vivo required divalent binding, as Fab fragments did not reduce NP colonization or alter ST3 gene expression. In vitro , 1E2 induced dose-dependent ST3 growth arrest and altered piuB and dpr expression, whereas an opsonic PPS3 MAb, 5F6, did not. 1E2-treated bacteria were more sensitive to hydrogen peroxide and the iron-requiring antibiotic streptonigrin, suggesting that 1E2 may increase iron import and enhance sensitivity to oxidative stress. Finally, 1E2 also induced rapid capsule shedding in vitro , suggesting that this may initiate 1E2-induced changes in sensitivity to oxidative stress and gene expression. Our data reveal a novel mechanism of direct, antibody-mediated antibacterial activity that could inform new directions in antipneumococcal therapy and vaccine development.

Download Full-text

Discovery of a novel class of highly conserved vaccine antigens using genomic scale antigenic fingerprinting of pneumococcus with human antibodies

Journal of Experimental Medicine ◽

10.1084/jem.20071168 ◽

2007 ◽

Vol 205 (1) ◽

pp. 117-131 ◽

Cited By ~ 193

Author(s):

Carmen Giefing ◽

Andreas L. Meinke ◽

Markus Hanner ◽

Tamás Henics ◽

Duc Bui Minh ◽

...

Keyword(s):

Animal Studies ◽

Group B Streptococcus ◽

The Elderly ◽

In Vitro Assays ◽

Human Pathogens ◽

Protein Antigens ◽

Lethal Sepsis ◽

Protective Antibodies ◽

Group B

Pneumococcus is one of the most important human pathogens that causes life-threatening invasive diseases, especially at the extremities of age. Capsular polysaccharides (CPSs) are known to induce protective antibodies; however, it is not feasible to develop CPS-based vaccines that cover all of the 90 disease-causing serotypes. We applied a genomic approach and described the antibody repertoire for pneumococcal proteins using display libraries expressing 15–150 amino acid fragments of the pathogen's proteome. Serum antibodies of exposed, but not infected, individuals and convalescing patients identified the ANTIGENome of pneumococcus consisting of ∼140 antigens, many of them surface exposed. Based on several in vitro assays, 18 novel candidates were preselected for animal studies, and 4 of them showed significant protection against lethal sepsis. Two lead vaccine candidates, protein required for cell wall separation of group B streptococcus (PcsB) and serine/threonine protein kinase (StkP), were found to be exceptionally conserved among clinical isolates (>99.5% identity) and cross-protective against four different serotypes in lethal sepsis and pneumonia models, and have important nonredundant functions in bacterial multiplication based on gene deletion studies. We describe for the first time opsonophagocytic killing activity for pneumococcal protein antigens. A vaccine containing PcsB and StkP is intended for the prevention of infections caused by all serotypes of pneumococcus in the elderly and in children.

Download Full-text

Antibody against Surface-Bound C5a Peptidase Is Opsonic and Initiates Macrophage Killing of Group B Streptococci

Infection and Immunity ◽

10.1128/iai.69.4.2302-2308.2001 ◽

2001 ◽

Vol 69 (4) ◽

pp. 2302-2308 ◽

Cited By ~ 48

Author(s):

Qi Cheng ◽

Brian Carlson ◽

Sub Pillai ◽

Ron Eby ◽

Lorri Edwards ◽

...

Keyword(s):

Whole Blood ◽

Capsular Polysaccharide ◽

Vaccine Development ◽

Primary Cultures ◽

Surface Protein ◽

Mouse Bone Marrow ◽

Group B Streptococci ◽

Protective Antibodies ◽

Group B

ABSTRACT The capsular polysaccharides of group B streptococci (GBS) are a primary focus of vaccine development. Immunogenicity and long-lasting protection are best achieved by conjugating polysaccharides to a T-cell-dependent protein antigen. Streptococcal C5a peptidase (SCPB) is a conserved surface protein that is expressed by all streptococcal serotypes tested to date, and it is a possible carrier protein that could itself induce a protective immune response. Clearance of GBS from lungs, mucosal surfaces, or blood probably depends on the opsonophagocytic response of tissue-specific macrophages and polymorphonuclear leukocytes (PMNs). In this study, we examined the potential of antibody directed against SCPB from a serotype II strain to enhance the capacity of mouse bone marrow macrophages (from primary cultures) and human PMNs in whole blood to kill GBS in vitro. Our experiments demonstrated that Streptococcus serotypes Ia, Ib, II, III, and V, preopsonized with anti-SCPB antibody, were killed more rapidly by cultured macrophages and PMNs in whole blood than were nonopsonized GBS. The increased rate of killing was accompanied by an increased macrophage oxidative burst. Furthermore, opsonization was serotype transparent. Immunization with SCPB conjugated to capsular polysaccharide type III produced polysaccharide-specific antibodies. It is interesting that this antiserum promoted serotype-independent killing of streptococci. These data support the use of SCPB in a GBS polysaccharide conjugate vaccine. SCPB not only enhanced the immunogenicity of polysaccharide components of the vaccine, but it might also induce additional serotype-independent protective antibodies.

Download Full-text