Hyaluronic acid capsule modulates M protein-mediated adherence and acts as a ligand for attachment of group A Streptococcus to CD44 on human keratinocytes

J Clin Invest. 1998 Apr 15;101(8):1708-16. doi: 10.1172/JCI2121.


We used wild-type and isogenic mutant strains of group A Streptococcus (GAS) that expressed M protein, capsule, or both to study the function of M protein and the hyaluronic acid capsular polysaccharide in attachment of GAS to human keratinocytes. Types 6 and 24, but not type 18, M protein were found to mediate attachment of GAS to soft palate or skin keratinocytes, but this interaction was prevented by the hyaluronic acid capsule on highly encapsulated, or mucoid, strains. Monoclonal antibody to CD44, the principal hyaluronic acid-binding receptor on keratinocytes, inhibited attachment of both highly encapsulated and poorly encapsulated wild type strains of GAS, but not the attachment of acapsular mutants. Transfection of K562 cells with cDNA encoding human CD44 conferred the capacity to bind each of six wild-type strains of GAS, but not to bind acapsular mutants. Because, in contrast to other potential adhesins, the group A streptococcal capsule is both highly conserved and surface-exposed, it may serve as a universal adhesin for attachment of diverse strains of GAS to keratinocytes of the pharyngeal mucosa and the skin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / metabolism
  • Antigens, Bacterial*
  • Bacterial Adhesion / genetics
  • Bacterial Adhesion / physiology*
  • Bacterial Outer Membrane Proteins*
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Carrier Proteins*
  • Cells, Cultured
  • DNA Primers / genetics
  • Humans
  • Hyaluronan Receptors / genetics
  • Hyaluronan Receptors / metabolism*
  • Hyaluronic Acid / genetics
  • Hyaluronic Acid / metabolism*
  • Keratinocytes / immunology*
  • Keratinocytes / metabolism
  • Keratinocytes / microbiology*
  • Ligands
  • Microscopy, Fluorescence
  • Mutation
  • Polymerase Chain Reaction
  • Streptococcal Infections / etiology
  • Streptococcus pyogenes / genetics
  • Streptococcus pyogenes / metabolism*
  • Streptococcus pyogenes / pathogenicity
  • Transfection


  • Adhesins, Bacterial
  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • DNA Primers
  • Hyaluronan Receptors
  • Ligands
  • streptococcal M protein
  • Hyaluronic Acid