Changes in Capsular Serotype Alter the Surface Exposure of Pneumococcal Adhesins and Impact Virulence

We examined the contribution of serotype on Streptococcus pneumoniae adhesion and virulence during respiratory tract infection using a panel of isogenic TIGR4 (serotype 4) mutants expressing the capsule types 6A (+6A), 7F (+7F) and 23F (+23F) as well as a deleted and restored serotype 4 (+4) control strain. Immunoblots, bacterial capture assays with immobilized antibody, and measurement of mean fluorescent intensity by flow cytometry following incubation of bacteria with antibody, all determined that the surface accessibility, but not total protein levels, of the virulence determinants Pneumococcal surface protein A (PspA), Choline binding protein A (CbpA), and Pneumococcal serine-rich repeat protein (PsrP) changed with serotype. In vitro, bacterial adhesion to Detroit 562 pharyngeal or A549 lung epithelial cells was modestly but significantly altered for +6A, +7F and +23F. In a mouse model of nasopharyngeal colonization, the number of +6A, +7F, and +23F pneumococci in the nasopharynx was reduced 10 to 100-fold versus +4; notably, only mice challenged with +4 developed bacteremia. Intratracheal challenge of mice confirmed that capsule switch strains were highly attenuated for virulence. Compared to +4, the +6A, +7F, and +23F strains were rapidly cleared from the lungs and were not detected in the blood. In mice challenged intraperitoneally, a marked reduction in bacterial blood titers was observed for those challenged with +6A and +7F versus +4 and +23F was undetectable. These findings show that serotype impacts the accessibility of surface adhesins and, in particular, affects virulence within the respiratory tract. They highlight the complex interplay between capsule and protein virulence determinants.

[1]  T. Hirai,et al.  Distribution and clonal relationship of cell surface virulence genes among Streptococcus pneumoniae isolates in Japan. , 2011, Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases.

[2]  C. Donati,et al.  The Streptococcus pneumoniae Pilus-1 Displays a Biphasic Expression Pattern , 2011, PloS one.

[3]  C. Whitney,et al.  Prevention of pneumococcal disease among infants and children - use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine - recommendations of the Advisory Committee on Immunization Practices (ACIP). , 2010, MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports.

[4]  Peng‐jun Lu,et al.  Pneumococcal polysaccharide vaccination among adults aged 65 years and older, U.S., 1989-2008. , 2010, American journal of preventive medicine.

[5]  C. Orihuela,et al.  PsrP, a Protective Pneumococcal Antigen, Is Highly Prevalent in Children with Pneumonia and Is Strongly Associated with Clonal Type , 2010, Clinical and Vaccine Immunology.

[6]  S. Meri,et al.  The Capsular Serotype of Streptococcus pneumoniae Is More Important than the Genetic Background for Resistance to Complement , 2010, Infection and Immunity.

[7]  R. Adegbola,et al.  Serotype-Related Variation in Susceptibility to Complement Deposition and Opsonophagocytosis among Clinical Isolates of Streptococcus pneumoniae , 2010, Infection and Immunity.

[8]  C. Orihuela,et al.  The Pneumococcal Serine-Rich Repeat Protein Is an Intra-Species Bacterial Adhesin That Promotes Bacterial Aggregation In Vivo and in Biofilms , 2010, PLoS pathogens.

[9]  Sam P. Brown,et al.  Within-Host Competition Drives Selection for the Capsule Virulence Determinant of Streptococcus pneumoniae , 2010, Current Biology.

[10]  C. Orihuela,et al.  Pneumococcal microbial surface components recognizing adhesive matrix molecules targeting of the extracellular matrix , 2010, Molecular microbiology.

[11]  R. Rappuoli,et al.  Molecular architecture of Streptococcus pneumoniae TIGR4 pili , 2009, The EMBO journal.

[12]  J. Weiser,et al.  Streptococcus pneumoniae Resistance to Complement-Mediated Immunity Is Dependent on the Capsular Serotype , 2009, Infection and Immunity.

[13]  Jeremy S. Brown,et al.  The Streptococcuspneumoniae Capsule Inhibits Complement Activity and Neutrophil Phagocytosis by Multiple Mechanisms , 2009, Infection and Immunity.

[14]  T. Mitchell,et al.  The Effects of PspC on Complement-Mediated Immunity to Streptococcus pneumoniae Vary with Strain Background and Capsular Serotype , 2009, Infection and Immunity.

[15]  C. Orihuela,et al.  The Streptococcus pneumoniae adhesin PsrP binds to Keratin 10 on lung cells , 2009, Molecular microbiology.

[16]  S. Normark,et al.  Bacterial adhesins in host-microbe interactions. , 2009, Cell host & microbe.

[17]  E. Tuomanen,et al.  Laminin receptor initiates bacterial contact with the blood brain barrier in experimental meningitis models. , 2009, The Journal of clinical investigation.

[18]  S. Meri,et al.  Streptococcus pneumoniae Capsular Serotype 19F Is More Resistant to C3 Deposition and Less Sensitive to Opsonophagocytosis than Serotype 6B , 2008, Infection and Immunity.

[19]  E. Muñoz-Elías,et al.  Isolation of Streptococcus pneumoniae Biofilm Mutants and Their Characterization during Nasopharyngeal Colonization , 2008, Infection and Immunity.

[20]  C. Orihuela,et al.  Antibodies against PsrP, a novel Streptococcus pneumoniae adhesin, block adhesion and protect mice against pneumococcal challenge. , 2008, The Journal of infectious diseases.

[21]  Jeffrey N. Weiser,et al.  The role of Streptococcus pneumoniae virulence factors in host respiratory colonization and disease , 2008, Nature Reviews Microbiology.

[22]  R. Rappuoli,et al.  RrgA is a pilus-associated adhesin in Streptococcus pneumoniae , 2007, Molecular microbiology.

[23]  S. Normark,et al.  Capsule and d‐alanylated lipoteichoic acids protect Streptococcus pneumoniae against neutrophil extracellular traps , 2007, Cellular microbiology.

[24]  L. McDaniel,et al.  Pneumolysin, PspA, and PspC Contribute to Pneumococcal Evasion of Early Innate Immune Responses during Bacteremia in Mice , 2007, Infection and Immunity.

[25]  T. Peto,et al.  Capsular serotype-specific attack rates and duration of carriage of Streptococcus pneumoniae in a population of children. , 2006, The Journal of infectious diseases.

[26]  R. Gertz,et al.  Sequential multiplex PCR approach for determining capsular serotypes of Streptococcus pneumoniae isolates. , 2006, Journal of clinical microbiology.

[27]  E. Tuomanen,et al.  Identification of a Candidate Streptococcus pneumoniae Core Genome and Regions of Diversity Correlated with Invasive Pneumococcal Disease , 2006, Infection and Immunity.

[28]  R. Morona,et al.  Attachment of capsular polysaccharide to the cell wall of Streptococcus pneumoniae type 2 is required for invasive disease. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[29]  A. Porgador,et al.  Pneumococcal 6‐phosphogluconate‐dehydrogenase, a putative adhesin, induces protective immune response in mice , 2006, Clinical and experimental immunology.

[30]  E. Tuomanen,et al.  Multifunctional Role of Choline Binding Protein G in Pneumococcal Pathogenesis , 2006, Infection and Immunity.

[31]  S. Hammerschmidt,et al.  Versatility of pneumococcal surface proteins. , 2006, Microbiology.

[32]  Tamara Pilishvili,et al.  Changing epidemiology of invasive pneumococcal disease among older adults in the era of pediatric pneumococcal conjugate vaccine. , 2005, JAMA.

[33]  Jeremy S. Brown,et al.  Additive Inhibition of Complement Deposition by Pneumolysin and PspA Facilitates Streptococcus pneumoniae Septicemia 1 , 2005, The Journal of Immunology.

[34]  A. Hocke,et al.  Illustration of Pneumococcal Polysaccharide Capsule during Adherence and Invasion of Epithelial Cells , 2005, Infection and Immunity.

[35]  E. Tuomanen,et al.  Tissue-specific contributions of pneumococcal virulence factors to pathogenesis. , 2004, The Journal of infectious diseases.

[36]  R. Morona,et al.  The effect that mutations in the conserved capsular polysaccharide biosynthesis genes cpsA, cpsB, and cpsD have on virulence of Streptococcus pneumoniae. , 2004, The Journal of infectious diseases.

[37]  G. Pozzi,et al.  Pneumococcal Surface Protein C Contributes to Sepsis Caused by Streptococcus pneumoniae in Mice , 2004, Infection and Immunity.

[38]  A. Sandgren,et al.  Effect of clonal and serotype-specific properties on the invasive capacity of Streptococcus pneumoniae. , 2004, The Journal of infectious diseases.

[39]  M. Ramirez,et al.  Serotyping Streptococcus pneumoniae by Multiplex PCR , 2003, Journal of Clinical Microbiology.

[40]  D. Briles,et al.  Both Family 1 and Family 2 PspA Proteins Can Inhibit Complement Deposition and Confer Virulence to a Capsular Serotype 3 Strain of Streptococcus pneumoniae , 2003, Infection and Immunity.

[41]  G. G. Hardy,et al.  Genetic Alteration of Capsule Type but Not PspA Type Affects Accessibility of Surface-Bound Complement and Surface Antigens of Streptococcus pneumoniae , 2003, Infection and Immunity.

[42]  M. Rohde,et al.  The pavA gene of Streptococcus pneumoniae encodes a fibronectin‐binding protein that is essential for virulence , 2001, Molecular microbiology.

[43]  S. Salzberg,et al.  Complete Genome Sequence of a Virulent Isolate of Streptococcus pneumoniae , 2001, Science.

[44]  L. McDaniel,et al.  PspC, a Pneumococcal Surface Protein, Binds Human Factor H , 2001, Infection and Immunity.

[45]  E. Tuomanen,et al.  The Polymeric Immunoglobulin Receptor Translocates Pneumococci across Human Nasopharyngeal Epithelial Cells , 2000, Cell.

[46]  S. Romero-Steiner,et al.  Relationship between cell surface carbohydrates and intrastrain variation on opsonophagocytosis of Streptococcus pneumoniae. , 1999, Infection and immunity.

[47]  Pneumococcal vaccines. WHO position paper. , 1999, Releve epidemiologique hebdomadaire.

[48]  J. Weiser,et al.  Association of intrastrain phase variation in quantity of capsular polysaccharide and teichoic acid with the virulence of Streptococcus pneumoniae. , 1998, The Journal of infectious diseases.

[49]  J. Paton,et al.  Uptake of Streptococcus pneumoniae by respiratory epithelial cells , 1996, Infection and immunity.

[50]  J. P. Dillard,et al.  Effect of genetic switching of capsular type on virulence of Streptococcus pneumoniae , 1994, Infection and immunity.

[51]  D. Briles,et al.  Strong association between capsular type and virulence for mice among human isolates of Streptococcus pneumoniae , 1992, Infection and immunity.