M PROTEIN-MEDIATED ADHESION OF M-TYPE-24 STREPTOCOCCUS-PYOGENES STIMULATES RELEASE OF INTERLEUKIN-6 BY HEP-2 TISSUE-CULTURE CELLS

We investigated the contributions of lipoteichoic acid and M protein t o reversible and irreversible adhesion of group A streptococci and the effects of such adhesion on release of interleukin-6. Streptococci in which lipoteichoic acid was masked by the hyaluronate capsule were re adily washed from HEp-2 cells, indicating no attachment. Unencapsulate d, M-negative streptococci in which lipoteichoic acid was exposed were removed more slowly, indicating loose attachment. Only unencapsulated streptococci that expressed both lipoteichoic acid and M protein rema ined stably adherent to HEp-2 cells throughout multiple washes. Strept ococci expressing both M protein and lipoteichoic acid induced release of interleukin-6 from HEp-2 cells, whereas an isogenic, M-negative mu tant failed to induce release of interleukin-6, These data suggest tha t Lipoteichoic acid mediates reversible adhesion and that M protein is required for irreversible adhesion and for inducing release of interl eukin-6 from HEp-2 cells.