title: Antibody classes & subclasses induced by mucosal immunization of mice with Streptococcus pyogenes M6 protein & oligodeoxynucleotides containing CpG motifs.
abstract: OBJECTIVE
  Type-specific antibodies against M protein are critical for human protection as they enhance phagocytosis and are protective. An ideal vaccine for the protection against Streptococcus pyogenes would warrant mucosal immunity, but mucosally administered M-protein has been shown to be poorly immunogenic in animals. We used a recombinant M type 6 protein to immunize mice in the presence of synthetic oligodeoxynucleotides containing CpG motifs (immunostimulatory sequences: ISS) or cholera toxin (CT) to explore its possible usage in a mucosal vaccine.
  
  
  METHODS
  Mice were immunized by intranasal (in) or intradermal (id) administration with four doses at weekly intervals of M6-protein (10 microg/mouse) with or without adjuvant (ISS, 10 microg/mouse or CT, 0,5 microg/mouse). M6 specific antibodies were measured by enzyme linked immunosorbent assay using class and subclass specific monoclonal antibodies.
  
  
  RESULTS
  The use of ISS induced an impressive anti M-protein serum IgG response but when id administered was not detectable in the absence of adjuvant. When used in, M-protein in the presence of both ISS and CT induced anti M-protein IgA in the bronchoalveolar lavage, as well as specific IgG in the serum. IgG were able to react with serotype M6 strains of S. pyogenes. The level of antibodies obtained by immunizing mice in with M-protein and CT was higher in comparison to M-protein and ISS. The analysis of anti-M protein specific IgG subclasses showed high levels of IgG1, IgG2a and IgG2b, and low levels of IgG3 when ISS were used as adjuvant. Thus, in the presence of ISS, the ratio IgG2a/IgG1 and (IgG2a+IgG3)/IgG1 >1 indicated a type 1-like response obtained both in mucosally or systemically vaccinated mice.
  
  
  CONCLUSIONS
  Our study offers a reproducible model of anti-M protein vaccination that could be applied to test new antigenic formulations to induce an anti-group A Streptococcus (GAS) vaccination suitable for protection against the different diseases caused by this bacterium.
authors.affiliation: Istituto Superiore di Sanità, Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Teloni
authors.forename: C
authors.initials: C
authors.lastname: von Hunolstein
authors.forename: S
authors.initials: S
authors.lastname: Mariotti
authors.forename: S
authors.initials: S
authors.lastname: Donati
authors.forename: G
authors.initials: G
authors.lastname: Orefici
authors.forename: R
authors.initials: R
authors.lastname: Nisini
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000008:administration & dosage / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000008:administration & dosage / Q000276:immunology*; D001483:Base Sequence; D002352:Carrier Proteins / Q000008:administration & dosage / Q000276:immunology*; D018899:CpG Islands; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage / Q000276:immunology*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; C014689:streptococcal M protein