title: StreptInCor: a candidate vaccine epitope against S. pyogenes infections induces protection in outbred mice.
abstract: Infection with Streptococcus pyogenes (S. pyogenes) can result in several diseases, particularly in children. S. pyogenes M protein is the major virulence factor, and certain regions of its N-terminus can trigger autoimmune sequelae such as rheumatic fever in susceptible individuals with untreated group A streptococcal pharyngitis. In a previous study, we utilized a large panel of human peripheral blood cells to define the C-terminal protective epitope StreptInCor (medical identity), which does not induce autoimmune reactions. We recently confirmed the results in HLA-transgenic mice. In the present study, we extended the experimental assays to outbred animals (Swiss mice). Herein, we demonstrate high titers of StreptInCor-specific antibodies, as well as appropriate T-cell immune responses. No cross-reaction to cardiac myosin was detected. Additionally, immunized Swiss mice exhibited 87% survival one month after challenge with S. pyogenes. In conclusion, the data presented herein reinforce previous results in humans and animals and further emphasize that StreptInCor could be an effective and safe vaccine for the prevention of S. pyogenes infections.
authors.affiliation: Heart Institute, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Edilberto
authors.initials: E
authors.lastname: Postol
authors.forename: Raquel
authors.initials: R
authors.lastname: Alencar
authors.forename: Fabio T
authors.initials: FT
authors.lastname: Higa
authors.forename: Samar
authors.initials: S
authors.lastname: Freschi de Barros
authors.forename: Lea M F
authors.initials: LM
authors.lastname: Demarchi
authors.forename: Jorge
authors.initials: J
authors.lastname: Kalil
authors.forename: Luiza
authors.initials: L
authors.lastname: Guilherme
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001422:Bacterial Adhesion / Q000276:immunology; D001428:Bacterial Vaccines / Q000737:chemistry / Q000276:immunology*; D001947:Breeding; D002460:Cell Line; D049109:Cell Proliferation; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D013045:Species Specificity; D013154:Spleen / Q000166:cytology; D013290:Streptococcal Infections / Q000097:blood / Q000235:genetics / Q000517:prevention & control*; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000502:physiology*; D022223:Vaccines, Subunit / Q000737:chemistry / Q000276:immunology*
chemical_list: D001428:Bacterial Vaccines; D000939:Epitopes; D007074:Immunoglobulin G; D022223:Vaccines, Subunit