Genetic Alteration of Capsule Type but Not PspA Type Affects Accessibility of Surface-Bound Complement and Surface Antigens of Streptococcus pneumoniae

ABSTRACT The Streptococcus pneumoniae capsular polysaccharides and pneumococcal surface protein A (PspA) are major determinants of virulence that are antigenically variable and capable of eliciting protective immune responses. By genetically switching the pspA genes of the capsule type 2 strain D39 and the capsule type 3 strain WU2, we showed that the different abilities of antibody to PspA to protect against these strains was not related to the PspA type expressed. Similarly, the level of specific antibody binding to PspA, other surface antigens, and surface-localized C3b did not depend on the PspA type but instead was correlated with the capsule type. The type 3 strain WU2 and an isogenic derivative of D39 that expresses the type 3 capsule bound nearly identical amounts of antibody to PspA and other surface antigens, and these amounts were less than one-half the amount observed with the type 2 parent strain D39. Expression of the type 3 capsule in D39 also reduced the amount of C3b deposited and its accessibility to antibody, resulting in a level intermediate between the levels observed with WU2 and D39. Despite these effects, the capsule type was not the determining factor in anti-PspA-mediated protection, as both D39 and its derivative expressing the type 3 capsule were more resistant to protection than WU2. The specific combination of PspA and capsule type also did not determine the level of protection. The capsule structure is thus a major determinant in accessibility of surface antigens to antibody, but certain strains appear to express other factors that can influence antibody-mediated protection.

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Pneumococcal Surface Protein C Contributes to Sepsis Caused by Streptococcus pneumoniae in Mice

Infection and Immunity ◽

10.1128/iai.72.5.3077-3080.2004 ◽

2004 ◽

Vol 72 (5) ◽

pp. 3077-3080 ◽

Cited By ~ 47

Author(s):

Francesco Iannelli ◽

Damiana Chiavolini ◽

Susanna Ricci ◽

Marco Rinaldo Oggioni ◽

Gianni Pozzi

Keyword(s):

Streptococcus Pneumoniae ◽

Protein C ◽

Lethal Dose ◽

Surface Protein ◽

Infection Model ◽

Wild Type ◽

Mutant Strains ◽

Type 3

ABSTRACT The role of pneumococcal surface protein C (PspC; also called SpsA, CbpA, and Hic) in sepsis by Streptococcus pneumoniae was investigated in a murine infection model. The pspC gene was deleted in strains D39 (type 2) and A66 (type 3), and the mutants were tested by being injected intravenously into mice. The animals infected with the mutant strains showed a significant increase in survival, with the 50% lethal dose up to 250-fold higher than that for the wild type. Our findings indicate that PspC affords a decisive contribution to sepsis development.

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Relative Roles of Genetic Background and Variation in PspA in the Ability of Antibodies to PspA To Protect against Capsular Type 3 and 4 Strains of Streptococcus pneumoniae

Infection and Immunity ◽

10.1128/iai.71.8.4498-4505.2003 ◽

2003 ◽

Vol 71 (8) ◽

pp. 4498-4505 ◽

Cited By ~ 35

Author(s):

Hazeline Roche ◽

Bing Ren ◽

Larry S. McDaniel ◽

Anders Håkansson ◽

David E. Briles

Keyword(s):

Streptococcus Pneumoniae ◽

Genetic Background ◽

Protein A ◽

Surface Protein ◽

Genetically Engineered ◽

Capsular Type ◽

Single Family ◽

Fatal Infection ◽

Human Use ◽

Type 3

ABSTRACT Pneumococcal surface protein A (PspA) is able to elicit antibodies in mice and humans that can protect mice against fatal infection with Streptococcus pneumoniae. It has been observed that immunization with a single family 1 PspA can protect mice against infections with capsular type 3 or 6B strains expressing PspA family 1 or 2. However, several studies have shown that immunity to PspA is less efficacious against several capsular type 4 strains than against strains of capsular types 3, 6A, and 6B. To determine whether the greater difficulty in protecting against capsular type 4 strains resulted from differences in their PspAs or from differences in their genetic backgrounds, we performed protection experiments using four different challenge strains: a capsular type 3 strain expressing a family 1 PspA (WU2), a capsular type 4 strain expressing a family 2 PspA (TIGR4), and genetically engineered variants of WU2 and TIGR4 expressing each other's PspAs. Prior to infection, the mice were immunized with recombinant family 1 or family 2 PspA. The results revealed that much of the difficulty in protecting against capsular type 4 strains was eliminated when mice were immunized with a homologous PspA of the same PspA family. However, regardless of which PspA the strains expressed, those on the TIGR4 background were about twice as hard to protect against as WU2 strains expressing the same PspA based on the efficacy rates seen in our experiments. These results point out the importance of including more than one PspA in any PspA vaccines developed for human use.

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Modified Opsonization, Phagocytosis, and Killing Assays To Measure Potentially Protective Antibodies against Pneumococcal Surface Protein A

Clinical and Vaccine Immunology ◽

10.1128/cvi.00371-13 ◽

2013 ◽

Vol 20 (10) ◽

pp. 1549-1558 ◽

Cited By ~ 16

Author(s):

Calvin C. Daniels ◽

Kyung-Hyo Kim ◽

Robert L. Burton ◽

Shaper Mirza ◽

Melissa Walker ◽

...

Keyword(s):

Capsular Polysaccharide ◽

Protein A ◽

Surface Protein ◽

Pneumococcal Surface Protein A ◽

Target Strain ◽

Human Sera ◽

Protective Antibodies ◽

Normal Human ◽

Type 3

ABSTRACTThe standard opsonophagocytosis killing assay (OPKA) for antibodies to pneumococcal capsular polysaccharide was modified to permit an evaluation of the protection-mediating antibodies to pneumococcal surface protein A (PspA). We found that by increasing the incubation time with the complement and phagocytes from 45 min to 75 min, the protective activity was readily detected. In another modification, we used a capsule type 2 target strain that expressed PspA but not pneumococcal surface protein C (PspC). With these modifications separately or in combination, rabbit antisera to the recombinant α-helical or proline-rich domains of PspA mediated >50% killing of the target strain. The ability of normal human sera to mediate the killing of pneumococci in this modified OPKA correlated with their levels of antibodies to PspA and their ability to protect mice against fatal infection with a type 3 strain. Passive protection of mice against pneumococci and killing in the modified OPKA were lost when normal human sera were adsorbed with recombinant PspA (rPspA) on Sepharose, thus supporting the potential utility of the modified OPKA to detect protective antibodies to PspA. In the standard OPKA, monoclonal antibodies to PspA were strongly protective in the presence of subprotective amounts of anti-capsule. Thus, the currently established high-throughput OPKA for antibodies to capsule could be modified in one of two ways to permit an evaluation of the opsonic efficacy of antibodies to PspA.

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PsaA (pneumococcal surface adhesin A) and PspA (pneumococcal surface protein A) DNA vaccines induce humoral and cellular immune responses against Streptococcus pneumoniae

Vaccine ◽

10.1016/s0264-410x(01)00395-4 ◽

2001 ◽

Vol 20 (5-6) ◽

pp. 805-812 ◽

Cited By ~ 33

Author(s):

Eliane N. Miyaji ◽

Waldely O. Dias ◽

Márcia Gamberini ◽

Vera C.B.C. Gebara ◽

Rocilda P.F. Schenkman ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Immune Responses ◽

Dna Vaccines ◽

Protein A ◽

Surface Protein ◽

Cellular Immune Responses ◽

Pneumococcal Surface Protein A ◽

Cellular Immune

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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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DNA vaccines expressing pneumococcal surface protein A (PspA) elicit protection levels comparable to recombinant protein

Journal of Medical Microbiology ◽

10.1099/jmm.0.46217-0 ◽

2006 ◽

Vol 55 (4) ◽

pp. 375-378 ◽

Cited By ~ 14

Author(s):

Daniela M. Ferreira ◽

Eliane N. Miyaji ◽

Maria Leonor S. Oliveira ◽

Michelle Darrieux ◽

Ana Paula M. Arêas ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Recombinant Protein ◽

Dna Vaccines ◽

Protein A ◽

Surface Protein ◽

Humoral Response ◽

Cost Effective ◽

Promising Candidate ◽

Pneumococcal Surface Protein A ◽

Antibody Levels

Pneumococcal surface protein A (PspA) is a promising candidate for the development of cost-effective vaccines against Streptococcus pneumoniae. In the present study, BALB/c mice were immunized with DNA vaccine vectors expressing the N-terminal region of PspA. Animals immunized with a vector expressing secreted PspA developed higher levels of antibody than mice immunized with the vector expressing the antigen in the cytosol. However, both immunogens elicited similar levels of protection against intraperitoneal challenge. Furthermore, immunization with exactly the same fragment in the form of a recombinant protein, with aluminium hydroxide as an adjuvant, elicited even higher antibody levels, but this increased humoral response did not correlate with enhanced protection. These results show that DNA vaccines expressing PspA are able to elicit protection levels comparable to recombinant protein, even though total anti-PspA IgG response is considerably lower.

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Assignment of Weight-Based Immunoglobulin G1 (IgG1) and IgG2 Units in Antipneumococcal Reference Serum Lot 89-S(F) for Pneumococcal Polysaccharide Serotypes 1, 4, 5, 7F, 9V, and 18C

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.12.1.218-223.2005 ◽

2005 ◽

Vol 12 (1) ◽

pp. 218-223 ◽

Cited By ~ 5

Author(s):

Daniel J. Sikkema ◽

Nancy A. Ziembiec ◽

Thomas R. Jones ◽

Stephen W. Hildreth ◽

Dace V. Madore ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Immune Responses ◽

Conjugate Vaccine ◽

Pneumococcal Conjugate Vaccine ◽

Pneumococcal Disease ◽

Pneumococcal Infection ◽

Capsular Polysaccharides ◽

Standardization Method ◽

Igg2 Antibody ◽

Reference Serum

ABSTRACT Weight-based assignments for immunoglobulin G1 (IgG1) and IgG2 subclass antibodies to Streptococcus pneumoniae capsular polysaccharides (PnPs) in antipneumococcal standard reference serum lot 89-S (lot 89-S), also known as lot 89-SF, have been determined for serotypes 1, 4, 5, 7F, 9V, and 18C. This extends the usefulness of lot 89-S beyond the IgG1 and IgG2 subclass assignments for serotypes 3, 6B, 14, 19F, and 23F made previously (A. Soininen, H. Kayhty, I. Seppala, and T. Wuorimaa, Clin. Diagn. Lab. Immunol. 5:561-566, 1998) to cover 11 major serotypes associated with the highest percentage of pneumococcal disease worldwide. A method of equivalence of absorbances in enzyme immunosorbent assays was used to determine the IgG1 and IgG2 antibody concentrations for the additional serotypes in lot 89-S, based on the subclass values previously assigned for PnPs serotypes 6B, 14, and 23F. This cross-standardization method assures consistency with previous antibody assignments in that reference serum. The newly assigned subclass values for serotype 9V, and previously assigned values for serotype 14, were used to quantitate PnPs antibodies in sera from adult and pediatric subjects immunized with a pneumococcal conjugate vaccine. There was a predominance of IgG1 anti-PnPs antibodies in pediatric sera and IgG2 anti-PnPs antibodies in the adult sera. The IgG1 and IgG2 subclass assignments for the 11 PnPs serotypes in antipneumococcal standard reference serum lot 89-S are useful for quantitating and characterizing immune responses to pneumococcal infection and vaccination regimens.

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