Functional epitope mapping of human interleukin-1 beta by surface plasmon resonance.
A panel of monoclonal antibodies to human IL-1 beta has been used to probe its conformational and functional characteristics. Real time antibody-protein interaction was assessed by surface plasmon resonance with a BIAcore apparatus, in order to determine the kinetic and thermodynamic parameters of the interaction and to map the recognition sites of the antibodies on the IL-1 beta surface. Topological analysis was thus compared to the inhibitory capacity of antibodies for IL-1 beta bioactivity and binding to the activating receptor IL-1RI. This functional mapping analysis allows the following hypothesis. At least two discrete areas of IL-1 beta, located within the sequences 133-147 and 177-186 (as defined by mAbs MhC1 and BRhD2, respectively), are apparently involved in IL-1RI-independent agonist activity, and thus possibly take part in the interaction with the receptor accessory protein IL-1RAcP. Another area in the 133-147 sequence (defined by mAb BRhC3) is involved in agonist binding to its receptor CDw121a (IL-1RI), whereas a site recognized by mAb BRhG5 within the sequence 218-243 is selectively responsible for non-agonist binding to the activating receptor. The loop between the 4th and the 5th beta-strand, at the open end of the IL-1 beta-barrel structure, may possibly take part in both non-agonist binding to IL-1RI and in the interaction with IL-1RAcP.
D'Ettorre
C
C
Dompé Research Center, L'Aquila, Italy.
De Chiara
G
G
Casadei
R
R
Boraschi
D
D
Tagliabue
A
A
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D015374:Biosensing Techniques; D018604:Epitope Mapping / Q000379:methods*; D000939:Epitopes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D053577:Interleukin-1 Receptor Accessory Protein; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000737:chemistry / Q000378:metabolism; D013816:Thermodynamics
D000911:Antibodies, Monoclonal; D000939:Epitopes; C507765:IL1RAP protein, human; D007375:Interleukin-1; D053577:Interleukin-1 Receptor Accessory Protein; D011506:Proteins; D017472:Receptors, Interleukin-1