Cyclic citrullinated peptide, antigen containing cyclic citrullinated peptide, reagent containing cyclic citrullinated peptide, kit containing cyclic citrullinated peptide and application

Abstract

The invention provides a cyclic citrullinated peptide, an antigen containing the cyclic citrullinated peptide, a reagent containing the cyclic citrullinated peptide, a kit containing the cyclic citrullinated peptide and application. In order to solve the problem that in the prior art, a disulfide bond at a cyclic structure of the cyclic citrullinated peptide is easy to break, so that an amino acid residue linear epitope outside a citrulline antibody recognition key region is exposed and recognized by other antibodies, and false positive occurs, the cyclic citrullinated peptide provided by the invention has the advantages that a peptide fragment at one end of a citrulline residue and a peptide fragment at the other end of the citrulline residue are connected into a ring through a carbon-sulfur bond. Compared with a disulfide bond formed between two cysteines C in natural cyclic citrulline, the carbon-sulfur bond is shorter in bond length, larger in bond energy and not easy to break, the probability that the amino acid residue linear epitope outside the citrulline antibody recognition key region is recognized by the other antibodies is lowered, false positive is lowered, and the clinical detection specificity of a cyclic citrullinated peptide antibody in RA disease diagnosis is improved.

Description

technical field [0001] The invention relates to the technical field of biological detection, in particular to a cyclic citrulline peptide, an antigen containing the peptide, a reagent, a kit and an application. Background technique [0002] Rheumatoid arthritis (Rheumatoid Arthritis, RA) is a chronic systemic disease of unknown etiology, mainly inflammatory synovitis, which affects about 1% of the world's population, and 75% of them are women. Rheumatoid arthritis is more common in middle-aged women, and the prevalence rate in my country is about 0.32% to 0.36%. RA can cause joint pain, stiffness, and swelling. Irreversible bone and joint damage may occur within 2 years of onset, which will eventually lead to joint ankylosis, deformity, and loss of function, and may cause various complications. [0003] For a long time, people expect to find some testing methods to help diagnosis, and some progress has been made. [0004] Detection of rheumatoid factor (RF) is the most com...

AI Technical Summary

Problems solved by technology

In practical applications, it was also found that the ring structure formed by the disulfide bond is not stable enough. After the disulfide bond is broken, the amino acid residues outside the key region recognized by the citrulline antibody form a linear epitope, which is easily recognized by other antibodies. lead to false positives

The anti-cyclic citrullinated peptide antibody detection kit developed based on the above existing sequence, in addition to the low sensitivity of clinical detection, was also detected in the serum of some other non-RA patients

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