FIBRONECTIN-BINDING BY STREPTOCOCCUS-MILLERI GROUP STRAINS AND PARTIAL CHARACTERIZATION OF THE FIBRONECTIN RECEPTOR OF STREPTOCOCCUS-ANGINOSUS F4

The Streptococcus milleri group were shown to bind fibronectin (Fn) to their cell-surface and this binding increased the adhesion of cells t o hydroxyapatite. The binding of Fn to Streptococcus anginosus F4 was studied in more detail. Fn binding to bacterial cells increased the as sociation of the bacteria with the polymorphonuclear leukocytes obtain ed from the peritoneal cavity of rats but did not increase killing of the bacteria. The cell-surface receptor was a protein of Mr 14 000 whi ch was released from cells after mutanolysin digestion. The binding wa s specific, with cells having a maximum number of binding sites per ce ll of 770. Electron microscopy, using gold-labelled Fn, localised the receptor to areas between daughter cells. (C) 1995 Academic Press Limi ted