StreptInCor: A Candidate Vaccine Epitope Against S. Pyogenes Infections Induces Protection in Outbred Mice

PLoS One. 2013 Apr 8;8(4):e60969. doi: 10.1371/journal.pone.0060969. Print 2013.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibody Specificity
  • Bacterial Adhesion / immunology
  • Bacterial Vaccines / chemistry
  • Bacterial Vaccines / immunology*
  • Breeding*
  • Cell Line
  • Cell Proliferation
  • Epitopes / immunology*
  • Female
  • Humans
  • Immunization
  • Immunoglobulin G / immunology
  • Mice
  • Molecular Sequence Data
  • Polymorphism, Genetic
  • Species Specificity
  • Spleen / cytology
  • Streptococcal Infections / blood
  • Streptococcal Infections / genetics
  • Streptococcal Infections / prevention & control*
  • Streptococcus pyogenes / immunology*
  • Streptococcus pyogenes / physiology*
  • Vaccines, Subunit / chemistry
  • Vaccines, Subunit / immunology*


  • Bacterial Vaccines
  • Epitopes
  • Immunoglobulin G
  • Vaccines, Subunit

Grant support

This study was supported by grants from the “Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)”, “Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)” and “Financiadora de Estudos e Projetos (FINEP)”, Brazil. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.