C-peptide immunogen, monoclonal antibody pair thereof, and application of monoclonal antibody pair to C-peptide magnetic particle chemical light-emitting immunoreagent

Abstract

The invention provides C-peptide immunogen. The C-peptide immunogen comprises a first complete antigen and a second complete antigen, wherein the first complete antigen is obtained by coupling a C-peptide N-terminal amino acid sequence and carrier protein; the second complete antigen is obtained by coupling a C-peptide C-terminal amino acid sequence and carrier protein; and the C-peptide N-terminal amino acid sequence of the first complete antigen is the 1st-12th site sequence in a C-peptide overall length sequence, and the C-peptide C-terminal amino acid sequence of the second complete antigen is the 18st-31st site sequence in the C-peptide overall length sequence. Through a conventional synthesis method, the antigens can be obtained, and are usable complete antigens. The preparation method is simple, and the obtained complete antigen is stable in structure. The monoclonal antibody pair obtained by animal immunization can respectively realize specific binding of the N terminal and theC terminal of C peptide, and the distance of binding sites is far, so that the condition that pairing cannot be performed caused by space steric hindrance can be avoided, and the requirements for development of antibodies for a C-peptide magnetic particle chemical light-emitting immunoreagent and other immunology diagnosis reagents can be met.

Description

technical field [0001] The invention relates to the technical field of immunodiagnosis, in particular to a C-peptide immunogen and a monoclonal antibody pair thereof. Background technique [0002] C-peptide is a product secreted by pancreatic islet cells, and has a common precursor proinsulin with insulin, such as Figure 5 As shown, one molecule of proinsulin is split into one molecule of insulin and one molecule of C-peptide after enzymatic cleavage. C-peptide is a straight-chain polypeptide composed of 31 amino acids. It has a slow clearance rate in the body, is hardly taken up by the liver and is not affected by exogenous insulin, and can reflect the level of endogenous insulin. [0003] C-peptide detection can help determine the type of diabetes; C-peptide detection is not interfered by islet antibodies, and can judge the islet function of insulin-treated patients; it can identify the cause of hypoglycemia, help the diagnosis of islet cell tumors and determine the effec...

AI Technical Summary

Problems solved by technology

First of all, C-peptide has low immunogenicity. In the preparation of antibodies, it needs to be linked with macromolecules to synthesize complete antigens. Commonly used methods, such as those disclosed in Chinese patents CN201210555678.7 and CN201810058354.X, all use the method of fusion expression of proteins. These methods require Gene synthesis, vector construction, prokaryotic expression, purification, etc., the operation is complex, and the carrier protein in the fusion protein is easy to change the structure of the target protein

Secondly, the C-peptide has only 31 amino acids, and the middle part of its peptide chain has a dominant epitope. Most of the binding points between the monoclonal antibody and the antigen obtained by using the complete molecule are concentrated in the middle region, which often cannot be paired due to steric resistance, which affects its Application in the development of diagnostic reagents

Images