Method for fixed-point labeled immunological reagent, labeled immunological reagent and application

Abstract

The invention relates to a method for a fixed-point labeled immunological reagent, the labeled immunological reagent and application. The method comprises the steps that firstly, the tail end of an antibody or an antigen is connected with a polypeptide fragment Leu-Pro-X-Thr-Gly; secondly, a signal molecule is connected with a polypeptide fragment the tail end of which contains at least three glycines; finally, the modified antibody or antigen, the modified signal molecule and transpeptidase Sortase A are mixed for a reaction to make the signal molecule quantitatively labeled on the antigen orthe antibody at a fixed point. A polyhydroxy compound is also added to the reaction as a protein protection agent, the activity of the antigen or the antibody can be effectively protected, the affinity damage, stability damage and the like, caused by transpeptidase Sortase A, of the antigen or the antibody are effectively avoided, the thermal stability and specificity of the labeled immunologicalreagent are greatly improved, the prepared labeled immunological reagent is small in batch difference, and the antigen or the antibody can also be greatly saved when the immunological reagent is applied to immunoassay.

Description

technical field [0001] The invention relates to a method for fixed-point labeling of an immune reagent, the labeled immune reagent and its application, and belongs to the technical field of labeled immunoassays. Background technique [0002] The earliest appearance of clinical immunoassay technology can be traced back to the end of the 19th century. Immunoprecipitation and immunoagglutination techniques are classic immunoassay techniques. The marker immunoassay technology developed on this basis can solve many clinical assays that cannot be solved by classical immunoassay techniques. question. [0003] Since the development of labeled immunoassay technology, the discovery and application of new markers to improve the sensitivity, specificity, stability and simplicity of immunoassay has been one of the main research directions of labeled immunoassay technology. The current markers include isotopes, Signaling molecules such as enzymes, luciferin, colloidal gold, and luminesce...

AI Technical Summary

Problems solved by technology

[0004] Labeled immunological reagents are usually made by labeling antibodies / antigens with signal molecules. The traditional labeling technology uses the lysine residues of antigens or antibodies to react with various activated signal molecules, and the lysine residues of antigens or antibodies There are a large number of bases (according to statistics, the 150kDa antibody has more than 100 lysine residues), and the labeling is random. Factors such as the type of marker, reaction temperature, feed ratio, reaction system size, reaction time, stirring and other factors will affect the labeling effect , the number and site of signal molecule labeling antibody / antigen cannot be well controlled. Too much signal molecule labeling on antigen / antibody will lead to impaired affinity and stability, etc. Signal molecule labeling on antigen / antibody The key sites (such as antigenic determinants) will directly lead to the inactivation of the antigen / antibody, and inappropriate position labeling will also cause changes in the physical properties of the antigen / antibody (such as hydrophobicity), resulting in the complete inability of the antigen / antibody to label the signal molecule. Therefore, the labeling process should be optimized to control the quantity and site of the signal molecule labeling immune reagents, and maintain the activity of the antigen or antibody, avoiding the damage of antigen or antibody affinity, stability damage, etc. important

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