ADHERENCE OF STREPTOCOCCUS-PNEUMONIAE TO IMMOBILIZED FIBRONECTIN

Adherence to extracellular matrix proteins, such as fibronectin, affor ds pathogens with a mechanism to invade injured epithelia. Streptococc us pneumoniae was found to adhere to immobilized fibronectin more avid ly than other streptococci and staphylococci do. Binding was dose, tim e, and temperature dependent. Trypsin treatment of the bacteria result ed in decreased binding, suggesting that the bacterial adhesive compon ent was a protein. Fragments of fibronectin generated by proteolysis o r by expression of recombinant gene segments were compared for the abi lity to bind pneumococci and to compete against bacterial binding to i mmobilized fibronectin. Fragments from the carboxy-terminal heparin bi nding domain were consistently active, suggesting that this region con tains the pneumococcal binding site, a region distinct from that suppo rting the attachment of most other bacteria.