Conjugation of PspA4Pro with Capsular Streptococcus pneumoniae Polysaccharide Serotype 14 Does Not Reduce the Induction of Cross-Reactive Antibodies

ABSTRACT Current pneumococcal vaccines are composed of bacterial polysaccharides as antigens, plain or conjugated to carrier proteins. While efficacious against vaccine serotypes, epidemiologic data show an increasing incidence of infections caused by nonvaccine serotypes of Streptococcus pneumoniae. The use of pneumococcal surface protein A (PspA) as a carrier protein in a conjugate vaccine could help prevent serotype replacement by increasing vaccine coverage and reducing selective pressure of S. pneumoniae serotypes. PspA is present in all pneumococcal strains, is highly immunogenic, and is known to induce protective antibodies. Based on its sequence, PspA has been classified into three families and six clades. A PspA fragment derived from family 2, clade 4 (PspA4Pro), was shown to generate antibodies with a broad range of cross-reactivity, across clades and families. Here, PspA4Pro was modified and conjugated to capsular polysaccharide serotype 14 (PS14). We investigated the impact of conjugation on the immune response induced to PspA4Pro and PS14. Mice immunized with the PS14-mPspA4Pro conjugate produced higher titers of anti-PS14 antibodies than the animals that received coadministered antigens. The conjugate induced antibodies with opsonophagocytic activity against PS14-carrying strains, as well as against a panel of strains bearing PspAs from five clades (encompassing families 1 and 2) bearing a non-PS14 serotype. Furthermore, mice immunized with PS14-mPspA4Pro were protected against nasal colonization with a nonrelated S. pneumoniae strain bearing PspA from clade 1, serotype 6B. These results demonstrate that the cross-reactivity mediated by PspA4Pro is retained following conjugation, supporting the use of PspA4 as a carrier protein in order to enhance pneumococcal vaccine coverage and encourage its further investigation as a candidate in future vaccine designs.

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A Common Food Glycan, Pectin, Shares an Antigen with Streptococcus pneumoniae Capsule

mSphere ◽

10.1128/msphere.00074-20 ◽

2020 ◽

Vol 5 (2) ◽

Author(s):

Moon H. Nahm ◽

Jigui Yu ◽

Jiri Vlach ◽

Maor Bar-Peled

Keyword(s):

Immune Response ◽

Streptococcus Pneumoniae ◽

Immune Responses ◽

Pneumococcal Vaccine ◽

Cross Reactivity ◽

Food Plants ◽

Content Type ◽

Plant Foods ◽

Vaccine Responses ◽

The Impact

ABSTRACT We are exposed daily to many glycans from bacteria and food plants. Bacterial glycans are generally antigenic and elicit antibody responses. It is unclear if food glycans’ sharing of antigens with bacterial glycans influences our immune responses to bacteria. We studied 14 different plant foods for cross-reactivity with monoclonal antibodies (MAbs) against 24 pneumococcal serotypes which commonly cause infections and are included in pneumococcal vaccines. Serotype 15B-specific MAb cross-reacts with fruit peels, and serotype 10A MAb cross-reacts with many natural and processed plant foods. The serotype 10A cross-reactive epitope is 1,6-β-galactosidase [βGal(1-6)], present in the rhamno-galacturonan I (RG-I) domain of pectin. Despite wide consumption of pectin, the immune response to 10A is comparable to the responses to other serotypes. An antipectin antibody can opsonize serotype 10A pneumococci, and the shared βGal(1-6) may be useful as a simple vaccine against 10A. Impact of food glycans should be considered in host-pathogen interactions and future vaccine designs. IMPORTANCE The impact of food consumption on vaccine responses is unknown. Streptococcus pneumoniae (the pneumococcus) is an important human pathogen, and its polysaccharide capsule is used as a vaccine. We show that capsule type 10A in a pneumococcal vaccine shares an antigenic epitope, βGal(1-6), with pectin, which is in many plant foods and is widely consumed. Immune response to 10A is comparable to that seen with other capsule types, and pectin ingestion may have little impact on vaccine responses. However, antibody to pectin can kill serotype 10A pneumococci and this shared epitope may be considered in pneumococcal vaccine designs.

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Recognition of pneumococcal isolates by antisera raised against PspA fragments from different clades

Journal of Medical Microbiology ◽

10.1099/jmm.0.47661-0 ◽

2008 ◽

Vol 57 (3) ◽

pp. 273-278 ◽

Cited By ~ 43

Author(s):

Michelle Darrieux ◽

Adriana T. Moreno ◽

Daniela M. Ferreira ◽

Fabiana C. Pimenta ◽

Ana Lúcia S. S. de Andrade ◽

...

Keyword(s):

Animal Models ◽

Vaccine Candidate ◽

Protein A ◽

Surface Protein ◽

Structural Diversity ◽

Cross Reactivity ◽

Terminal Region ◽

Hybrid Protein ◽

Pneumococcal Infections ◽

Clade 1

Pneumococcal surface protein A (PspA) is an important vaccine candidate against pneumococcal infections, capable of inducing protection in different animal models. Based on its structural diversity, it has been suggested that a PspA-based vaccine should contain at least one fragment from each of the two major families (family 1, comprising clades 1 and 2, and family 2, comprising clades 3, 4 and 5) in order to elicit broad protection. This study analysed the recognition of a panel of 35 pneumococcal isolates bearing different PspAs by antisera raised against the N-terminal regions of PspA clades 1 to 5. The antiserum to PspA clade 4 was found to show the broadest cross-reactivity, being able to recognize pneumococcal strains containing PspAs of all clades in both families. The cross-reactivity of antibodies elicited against a PspA hybrid including the N-terminal region of clade 1 fused to a shorter and more divergent fragment (clade-defining region, or CDR) of clade 4 (PspA1–4) was also tested, and revealed a strong recognition of isolates containing clades 1, 4 and 5, and weaker reactions with clades 2 and 3. The analysis of serum reactivity against different PspA regions further revealed that the complete N-terminal region rather than just the CDR should be included in an anti-pneumococcal vaccine. A PspA-based vaccine is thus proposed to be composed of the whole N-terminal region of clades 1 and 4, which could also be expressed as a hybrid protein.

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Distribution and Variation of Serotypes and Pneumococcal Surface Protein A Clades of Streptococcus pneumoniae Strains Isolated From Adult Patients With Invasive Pneumococcal Disease in Japan

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.617573 ◽

2021 ◽

Vol 11 ◽

Author(s):

Bin Chang ◽

Yuki Kinjo ◽

Masatomo Morita ◽

Kosuke Tamura ◽

Hiroshi Watanabe ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Invasive Pneumococcal Disease ◽

Pneumococcal Disease ◽

Protein A ◽

Surface Protein ◽

Vaccine Serotypes ◽

Pneumococcal Surface Protein A ◽

Clade 1 ◽

Almost All ◽

Candidate Antigen

Pneumococcal surface protein A (PspA) is a surface protein of Streptococcus pneumoniae that may be a candidate antigen for new pneumococcal vaccines. This study investigates the distribution of PspA clades of the causative strains of adult invasive pneumococcal disease (IPD) in Japan. Of the 1,939 strains isolated from cases of adult IPD during 2014–2019, the PspA clades of 1,932 (99.6%) strains were determined, and no pspA was detected in the remaining 7 strains (0.4%). PspA clades 1–6 were detected in 786 (40.5%), 291 (15.0%), 443 (22.8%), 369 (19.0%), 33 (1.7%), and 6 (0.3%) strains, respectively. New PspA clades (0.2%) were identified in two non-typeable and two serotype 35B pneumococci. The proportions of clade 1 and clade 2 showed significantly decreased and increased trends, respectively. Furthermore, the PspA clade of pneumococcal strains was partially serotype- and sequence type-dependent. The majority of strains belonging to serotypes contained in both the 13-valent pneumococcal conjugate vaccine (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPSV23) belonged to PspA clades 1 or 3. In contrast, the distribution of clades in non-vaccine serotypes was wider than that of vaccine serotype pneumococci. Our findings demonstrate that almost all pneumococcal strains from adult IPD express PspA clades 1–4, especially for non-vaccine serotypes. These results may be useful for the development of a new pneumococcal vaccine with PspA.

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Conjugation of Polysaccharide 6B from Streptococcus pneumoniae with Pneumococcal Surface Protein A: PspA Conformation and Its Effect on the Immune Response

Clinical and Vaccine Immunology ◽

10.1128/cvi.00754-12 ◽

2013 ◽

Vol 20 (6) ◽

pp. 858-866 ◽

Cited By ~ 20

Author(s):

Catia T. Perciani ◽

Giovana C. Barazzone ◽

Cibelly Goulart ◽

Eneas Carvalho ◽

Joaquin Cabrera-Crespo ◽

...

Keyword(s):

Immune Response ◽

Streptococcus Pneumoniae ◽

Conjugate Vaccine ◽

Reductive Amination ◽

Capsular Polysaccharide ◽

Protective Antigen ◽

Protein A ◽

Surface Protein ◽

Promising Alternative ◽

Pneumococcal Surface Protein A

ABSTRACTDespite the substantial beneficial effects of incorporating the 7-valent pneumococcal conjugate vaccine (PCV7) into immunization programs, serotype replacement has been observed after its widespread use. As there are many serotypes currently documented, the use of a conjugate vaccine relying on protective pneumococcal proteins as active carriers is a promising alternative to expand PCV coverage. In this study, capsular polysaccharide serotype 6B (PS6B) and recombinant pneumococcal surface protein A (rPspA), a well-known protective antigen fromStreptococcus pneumoniae, were covalently attached by two conjugation methods. The conjugation methodology developed by our laboratory, employing 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) as an activating agent through carboxamide formation, was compared with reductive amination, a classical methodology. DMT-MM-mediated conjugation was shown to be more efficient in coupling PS6B to rPspA clade 1 (rPspA1): 55.0% of PS6B was in the conjugate fraction, whereas 24% was observed in the conjugate fraction with reductive amination. The influence of the conjugation process on the rPspA1 structure was assessed by circular dichroism. According to our results, both conjugation processes reduced the alpha-helical content of rPspA; reduction was more pronounced when the reaction between the polysaccharide capsule and rPspA1 was promoted between the carboxyl groups than the amine groups (46% and 13%, respectively). Regarding the immune response, both conjugates induced functional anti-rPspA1 and anti-PS6B antibodies. These results suggest that the secondary structure of PspA1, as well as its reactive groups (amine or carboxyl) involved in the linkage to PS6B, may not play an important role in eliciting a protective immune response to the antigens.

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Evaluation of a Vaccine Formulation against Streptococcus pneumoniae Based on Choline-Binding Proteins

Clinical and Vaccine Immunology ◽

10.1128/cvi.00692-14 ◽

2014 ◽

Vol 22 (2) ◽

pp. 213-220 ◽

Cited By ~ 5

Author(s):

Eliane N. Miyaji ◽

Cintia F. M. Vadesilho ◽

Maria Leonor S. Oliveira ◽

André Zelanis ◽

David E. Briles ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Binding Proteins ◽

Choline Chloride ◽

Protein A ◽

Surface Protein ◽

Mass Spectrometry Analysis ◽

Effective Vaccine ◽

Lethal Challenge ◽

Content Type ◽

Spectrometry Analysis

ABSTRACTStreptococcus pneumoniaehas proteins that are attached to its surface by binding to phosphorylcholine of teichoic and lipoteichoic acids. These proteins are known as choline-binding proteins (CBPs). CBPs are an interesting alternative for the development of a cost-effective vaccine, and PspA (pneumococcal surface protein A) is believed to be the most important protective component among the different CBPs. We sought to use CBPs eluted from pneumococci as an experimental vaccine. Since PspA shows variability between isolates, we constructed strains producing different PspAs. We used the nonencapsulated Rx1 strain, which produces PspA from clade 2 (PspA2), to generate apspA-knockout strain (Rx1 ΔpspA) and strains expressing PspA from clade 1 (Rx1pspA1) and clade 4 (Rx1pspA4). We grew Rx1, Rx1 ΔpspA, Rx1pspA1, and Rx1pspA4in Todd-Hewitt medium containing 0.5% yeast extract and washed cells in 2% choline chloride (CC). SDS-PAGE analysis of the proteins recovered by a CC wash showed few bands, and the CBPs PspA and PspC (pneumococcal surface protein C) were identified by mass spectrometry analysis. Subcutaneous immunization of mice with these full-length native proteins without adjuvant led to significantly higher rates of survival than immunization with diluent after an intranasal lethal challenge with two pneumococcal strains and also after a colonization challenge with one strain. Importantly, immunization with recombinant PspA4 (rPspA4) without adjuvant did not elicit significant protection.

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Protection induced by pneumococcal surface protein A (PspA) is enhanced by conjugation to a Streptococcus pneumoniae capsular polysaccharide

Vaccine ◽

10.1016/j.vaccine.2008.03.038 ◽

2008 ◽

Vol 26 (23) ◽

pp. 2925-2929 ◽

Cited By ~ 16

Author(s):

Fátima C.L. Csordas ◽

Cátia T. Perciani ◽

Michelle Darrieux ◽

Viviane M. Gonçalves ◽

Joaquim Cabrera-Crespo ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Capsular Polysaccharide ◽

Protein A ◽

Surface Protein ◽

Pneumococcal Surface Protein A

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Controlled Inflammatory Responses in the Lungs Are Associated with Protection Elicited by a Pneumococcal Surface Protein A-Based Vaccine against a Lethal Respiratory Challenge with Streptococcus pneumoniae in Mice

Clinical and Vaccine Immunology ◽

10.1128/cvi.00171-12 ◽

2012 ◽

Vol 19 (9) ◽

pp. 1382-1392 ◽

Cited By ~ 14

Author(s):

Fernanda A. Lima ◽

Daniela M. Ferreira ◽

Adriana T. Moreno ◽

Patrícia C. D. Ferreira ◽

Giovana M. P. Palma ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Inflammatory Responses ◽

Protein A ◽

Surface Protein ◽

Necrosis Factor Alpha ◽

Content Type ◽

Pneumococcal Surface Protein A ◽

Lung Injuries ◽

Nasal Vaccine ◽

Respiratory Challenge

ABSTRACTStreptococcus pneumoniaeis a pathogen of great importance worldwide. We have previously described the efficacy of a nasal vaccine composed of the pneumococcal surface protein A and the whole-cell pertussis vaccine as an adjuvant against a pneumococcal invasive challenge in mice. Spread of bacteria to the bloodstream was probably prevented by the high levels of systemic antibodies induced by the vaccine, but bacteria were only cleared from the lungs 3 weeks later, indicating that local immune responses may contribute to survival. Here we show that a strict control of inflammatory responses in lungs of vaccinated mice occurs even in the presence of high numbers of pneumococci. This response was characterized by a sharp peak of neutrophils and lymphocytes with a simultaneous decrease in macrophages in the respiratory mucosa at 12 h postchallenge. Secretion of interleukin-6 (IL-6) and gamma interferon (IFN-γ) was reduced at 24 h postchallenge, and the induction of tumor necrosis factor alpha (TNF-α) secretion, observed in the first hours postchallenge, was completely abolished at 24 h. Before challenge and at 12 h postchallenge, vaccinated mice displayed higher numbers of CD4+T, CD8+T, and B lymphocytes in the lungs. However, protection still occurs in the absence of each of these cells during the challenge, indicating that other effectors may be related to the prevention of lung injuries in this model. High levels of mucosal anti-PspA antibodies were maintained in vaccinated mice during the challenge, suggesting an important role in protection.

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A Cross-Reactive Protein Vaccine Combined with PCV-13 Prevents Streptococcus pneumoniae- and Haemophilus influenzae-Mediated Acute Otitis Media

Infection and Immunity ◽

10.1128/iai.00253-19 ◽

2019 ◽

Vol 87 (10) ◽

Cited By ~ 2

Author(s):

Hannah M. Rowe ◽

Beth Mann ◽

Amy Iverson ◽

Aaron Poole ◽

Elaine Tuomanen ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Haemophilus Influenzae ◽

Otitis Media ◽

Capsular Polysaccharide ◽

Vaccine Coverage ◽

Acute Otitis Media ◽

Protein Vaccine ◽

Content Type ◽

Fusion Construct ◽

Reactive Protein

ABSTRACT Acute otitis media is one of the most common childhood infections worldwide. Currently licensed vaccines against the common otopathogen Streptococcus pneumoniae target the bacterial capsular polysaccharide and confer no protection against nonencapsulated strains or capsular types outside vaccine coverage. Mucosal infections such as acute otitis media remain prevalent, even those caused by vaccine-covered serotypes. Here, we report that a protein-based vaccine, a fusion construct of epitopes of CbpA to pneumolysin toxoid, confers effective protection against pneumococcal acute otitis media for non-PCV-13 serotypes and enhances protection for PCV-13 serotypes when coadministered with PCV-13. Having cross-reactive epitopes, the fusion protein also induces potent antibody responses against nontypeable Haemophilus influenzae and S. pneumoniae, engendering protection against acute otitis media caused by emerging unencapsulated otopathogens. These data suggest that augmenting capsule-based vaccination with conserved, cross-reactive protein-based vaccines broadens and enhances protection against acute otitis media.

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Relationship between Surface Accessibility for PpmA, PsaA, and PspA and Antibody-Mediated Immunity to Systemic Infection by Streptococcus pneumoniae

Infection and Immunity ◽

10.1128/iai.73.3.1304-1312.2005 ◽

2005 ◽

Vol 73 (3) ◽

pp. 1304-1312 ◽

Cited By ~ 57

Author(s):

Dennis O. Gor ◽

Xuedong Ding ◽

David E. Briles ◽

Michael R. Jacobs ◽

Neil S. Greenspan

Keyword(s):

Streptococcus Pneumoniae ◽

Capsular Polysaccharide ◽

Protein A ◽

Age Groups ◽

Pneumococcal Infection ◽

Systemic Infection ◽

Surface Protein ◽

Target Antigen ◽

Age Related ◽

Type 3

ABSTRACT Antibodies to capsular polysaccharide (PS) are protective against systemic infection by Streptococcus pneumoniae, but the large number of pneumococcal serogroups and the age-related immunogenicity of pure PS limit the utility of PS-based vaccines. In contrast, cell wall-associated proteins from different capsular serotypes can be cross-reactive and immunogenic in all age groups. Therefore, we evaluated three pneumococcal proteins with respect to relative accessibility to antibody, in the context of intact pneumococci, and their ability to elicit protection against systemic infection by encapsulated S. pneumoniae. Sequences encoding pneumococcal surface adhesin A (PsaA), putative protease maturation protein A (PpmA), and the N-terminal region of pneumococcal surface protein A (PspA) from S. pneumoniae strain A66.1 were cloned and expressed in Escherichia coli. The presence of genes encoding PsaA, PpmA, and PspA in 11 clinical isolates was examined by PCR, and the expression of these proteins by each strain was examined by Western blotting with antisera raised to the respective recombinant proteins. We used flow cytometry to demonstrate that PspA was readily detectable on the surface of the pneumococcal strains analyzed, whereas PsaA and PpmA were not. Consistent with these observations, mice with passively or actively acquired antibodies to PspA or type 3 PS were equivalently protected from homologous systemic challenge with type 3 pneumococci, whereas mice with passively or actively acquired antibodies to PsaA or PpmA were not effectively protected. These experiments support the hypothesis that the extent of protection against systemic pneumococcal infection is influenced by target antigen accessibility to circulating host antibodies.

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