Monoclonal antibodies to CNA, a collagen-binding microbial surface component recognizing adhesive matrix molecules, detach Staphylococcus aureus from a collagen substrate.
Previous studies showed that Staphylococcus aureus expresses a collagen-binding MSCRAMM (Microbial Surface Component Recognizing Adhesive Matrix Molecules), CNA, that is necessary and sufficient for S. aureus cells to adhere to cartilage and is a virulence factor in experimental septic arthritis. We have now used a monoclonal antibody (mAb) approach to further analyze the structure and function of CNA. 22 mAbs raised against the minimal ligand binding domain, CNA-(151-318), were shown to bind to the MSCRAMM with similar affinity. All mAbs appear to recognize conformation-dependent epitopes that were mapped throughout the CNA-(151-318) domain using a chimeric strategy where segments of CNA are grafted on ACE, a structurally related MSCRAMM from Enterococcus faecalis. These mAbs were able to inhibit (125)I-collagen binding to CNA-(151-318) as well as to intact S. aureus cells. They also interfered with the attachment of bacteria to collagen substrates. Furthermore, some of the mAbs could effectively displace (125)I-collagen bound to the bacteria. These displacing mAbs were also able to detach bacteria that had adhered to a collagen substrate in a preincubation, raising the possibility that some of the mAbs may be used as therapeutic agents.
Visai
L
L
Department of Biochemistry, University of Pavia, Viale Taramelli 3/B, I-27100 Pavia, Italy.
Xu
Y
Y
Casolini
F
F
Rindi
S
S
Höök
M
M
Speziale
P
P
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001422:Bacterial Adhesion / Q000276:immunology*; D001483:Base Sequence; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D017931:DNA Primers; D016023:Integrins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007457:Iodine Radioisotopes; D008969:Molecular Sequence Data; D038981:Receptors, Collagen; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000276:immunology*; D013329:Structure-Activity Relationship
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D017931:DNA Primers; D016023:Integrins; D007457:Iodine Radioisotopes; D038981:Receptors, Collagen