title: Recombinant tetravalent group A streptococcal M protein vaccine.
abstract: Previous studies have shown that the amino-terminal regions of group A streptococcal M proteins contain primarily protective (opsonic) epitopes and not tissue-cross-reactive epitopes. Limited primary structures from multiple serotypes of M protein containing only protective epitopes could potentially be linked together to form a broadly protective vaccine. The present studies were undertaken to determine the protective immunogenicity of a recombinant, multivalent hybrid molecule containing amino-terminal subunits of types 24, 5, 6, and 19 M proteins. Polymerase chain reaction primers were designed to amplify emm gene fragments ranging from 35 to 113 codons. The PCR products were ligated in tandem and inserted into pKK223-3. The tetravalent M protein that was purified from extracts of Escherichia coli migrated as a single band on SDS-PAGE with an apparent m.w. of 31 kDa. In immunoblot analyses, the hybrid protein reacted with serotype-specific antisera indicating that it contained all four M protein subunits. Rabbits immunized with the purified tetravalent M protein developed significant antibody levels against all four serotypes of native M proteins represented in the hybrid protein. None of the antisera cross-reacted with human tissues. The immune sera also opsonized all four serotypes of group A streptococci. Our data show that a hybrid protein containing subunits from multiple M proteins can evoke broadly protective immune responses without tissue-cross-reactive antibodies.
authors.affiliation: Department of Veterans Affairs Medical Center, Memphis, TN 38104.
authors.forename: J B
authors.initials: JB
authors.lastname: Dale
authors.forename: E Y
authors.initials: EY
authors.lastname: Chiang
authors.forename: J W
authors.initials: JW
authors.lastname: Lederer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000235:genetics*; D001483:Base Sequence; D001667:Binding, Competitive; D001770:Blood Bactericidal Activity; D002352:Carrier Proteins; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D009895:Opsonin Proteins; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D002352:Carrier Proteins; D009838:Oligodeoxyribonucleotides; D009895:Opsonin Proteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; C014689:streptococcal M protein