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Immune Cross-Opsonization Within emm Clusters Following Group A Streptococcus Skin Infection: Broadening the Scope of

Hannah R Frost1,2, Delphine Laho1,3, Martina L Sanderson-Smith4

  • 1Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia.

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America
|October 12, 2017
PubMed
Abstract

Insights

Immunity to Group A Streptococcus (GAS) skin infections can be broader than previously thought. This study shows cross-reactive immune responses to GAS M types, suggesting potential for multivalent vaccines.

Area of Science:

  • Immunology
  • Infectious Diseases
  • Vaccinology

Background:

  • Group A Streptococcus (GAS) skin infections are common globally, particularly in developing countries.
  • The GAS M protein is key for strain differentiation and elicits protective antibodies, but immunity was thought to be type-specific.
  • Recent findings suggest potential immune cross-reactivity between different GAS emm types.

Purpose of the Study:

  • To investigate human serological responses to GAS impetigo.
  • To explore cross-reactivity between different GAS emm types, focusing on specific emm clusters.

Main Methods:

  • Studied Fijian schoolchildren with GAS impetigo, analyzing pre- and postinfection sera.
  • Used enzyme-linked immunosorbent assays (ELISA) with M peptides and bactericidal assays.
  • Tested sera against infecting strains, emm cluster-related strains, and nonrelated strains.

Main Results:

  • A significant increase in antibody titers against the infecting GAS type was observed in 20 of 53 paired sera.
  • Over 50% of tested sera showed increased antibody titers to emm cluster-related M peptides.
  • Bactericidal assays revealed cross-reactive killing of GAS strains, particularly within emm clusters E4 and E6.

Conclusions:

  • Both type-specific and cross-reactive immune responses occur after GAS skin infections.
  • Cross-reactivity often aligns with emm clusters, supporting the hypothesis of broader immunity.
  • Findings offer new strategies for designing multivalent GAS vaccines with wider protective coverage.
Keywords:
Streptococcus pyogenesemm-clusterimmunityskin infectionvaccine

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