A kind of IgG1 Fc monomer and its application

Abstract

The invention belongs to the field of biotechnology, and specifically relates to an IgG1Fc monomer, a preparation method thereof, and an application thereof. The present invention aims at transforming the novel IgG1 Fc monomer sequence of the antibody IgG1 constant region, through antibody engineering technology to transform the Fc of the human antibody IgG1 constant region, so that its Fc dimer becomes an Fc monomer, and maintains the FcRn binding function, which has a very strong Low non-specific binding properties of irrelevant proteins. The main feature of the Fc monomer is that there are mutations in the T366, L368, P395, and K409 positions of the CH3 region of the antibody constant region, and it is highly expressed in prokaryotic cells. A pH-dependent The special binding mode binds FcRn, and has very low non-specific binding properties. Using this new type of Fc monomer, it can be fused or coupled with various proteins, polypeptides, small molecules, nucleic acids, etc. for different targets, so that the fused or coupled molecules have the characteristic of pH-dependent binding to FcRn.

Description

technical field [0001] The invention belongs to the field of biotechnology, and specifically relates to an IgG1 Fc monomer, a preparation method thereof, and an application thereof. Background technique [0002] Research has disclosed that there are currently three main long-acting technologies for protein drugs: PEG (polyethylene glycol) modification technology, HSA (human serum albumin) fusion technology, and Fc (human antibody Fc region) fusion technology. The three technologies all have their own weaknesses, among which the common key disadvantage is that there is a significant increase in the molecular weight of the fused or modified protein drug, and it often significantly reduces the yield and clinical efficacy of the fused protein drug; for example, human antibody The constant region Fc is a homodimer, its own molecular weight is already 60kDa, and the fusion protein can only be in the form of dimerization, which makes the molecular weight of the fusion protein often...

AI Technical Summary

Problems solved by technology

In the previous research of the present invention, a new method of multiple functional screening was used to transform the Fc region of human IgG1, and 1 billion (10 9 ) different Fc mutant molecules were screened for druggability, FcRn binding activity, etc., and constructed The Fc monomer molecule (mFc), whose molecular weight is only half of the IgG1 Fc region, completely retains the FcRn binding properties and Protein A / G binding properties of the antibody Fc region, and has a highly soluble expression in E. coli Excellent characteristics, the half-life in animals can be as long as about two days; then, during the research process, it was found that it has very strong non-specific binding properties, which may make mFc non-specific binding to unrelated proteins when used in vivo, which greatly limits its clinical application. use space

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