Screening serum biomarker of knee osteoarthritis using a phage display technique

ObjectivesTo screen serum biomarker of knee osteoarthritis (OA) using a phage random peptide library.Design and methodsA phage random peptide library of random peptide 12-mers was screened with purified immunoglobulin G (IgG) from sera of knee OA patients. Patients with knee rheumatoid arthritis (RA), hip OA, non-erosive hand OA or erosive hand OA, and healthy volunteers were used as controls.ResultsA phage clone with inserted peptide TGLESGHGPGDS (named KOA1) showed 90% positive reaction rate with the knee OA patients, significantly higher than that with the knee RA patients (27.8%), the non-erosive hand OA patients (34.3%), the erosive hand OA patients (31.3%) and the healthy controls (12.0%), but not the hip OA patients (82.5%).ConclusionsThe novel knee OA mimic peptide KOA1 identified with a random phage display peptide library and sera from knee OA patients could be a potential serum biomarker for knee OA.

► Identified a novel knee OA mimic peptide with random phage display peptide library.
► The knee OA mimic peptide (named KOA1) showed high diagnostic validity for knee OA.
► KOA1 showed no significant homology with other protein sequences.
► KOA1 is unlikely related to inflammation or cartilage degradation.