Antibody response to fibronectin-binding adhesin FnbpA in patients with Staphylococcus aureus infections.
We have analyzed antibody reactivity to a fibronectin-binding microbial surface component that recognizes adhesive matrix molecules (MSCRAMM) in blood plasma collected from patients with staphylococcal infections. All patients had elevated levels of anti-MSCRAMM antibodies compared to those of young children who, presumably, had not been exposed to staphylococcal infections. The anti-MSCRAMM antibodies preferentially reacted with the ligand-binding repeat domain of the adhesin. However, these antibodies did not inhibit fibronectin binding. Essentially, all patients had antibodies which specifically recognized the fibronectin-MSCRAMM complex but not the isolated components. Epitopes recognized by these anti-ligand-induced binding sites antibodies were found in each repeat unit of the MSCRAMM. These results demonstrate that staphylococci have bound fibronectin some time during infection and that each repeat unit in the MSCRAMM can engage in ligand binding. Furthermore, our previously proposed model, suggesting that an unordered structure in the MSCRAMM undergoes a conformational change upon ligand binding (K. House-Pompeo, Y. Xu, D. Joh, P. Speziale, and M. Höök, J. Biol. Chem. 271:1379-1384, 1996), is presumably operational in patients during infections.
Department of Biochemistry, University of Pavia, 27100 Pavia, Italy.
F
F
Casolini
L
L
Visai
D
D
Joh
P G
PG
Conaldi
A
A
Toniolo
M
M
Höök
P
P
Speziale
D018829:Adhesins, Bacterial; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000276:immunology* / Q000378:metabolism; D002352:Carrier Proteins / Q000276:immunology*; D002675:Child, Preschool; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology; D005353:Fibronectins / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000378:metabolism; D008024:Ligands; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D013203:Staphylococcal Infections / Q000097:blood / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D000939:Epitopes; D005353:Fibronectins; D007074:Immunoglobulin G; D008024:Ligands; D010446:Peptide Fragments; C048165:adhesin, Staphylococcus aureus; C078635:fibronectin-binding proteins, bacterial