Antibody expression vector with three selection markers and application

Abstract

The invention discloses an antibody expression vector with three selection marker s The antibody expression vector comprises an expression cassette I and an expression cassette II in the same vector, the expression cassette II is adjacent to the expression cassette I in a forward arrangement manner, and in the expression cassette I, a puromycin resistance gene PuroR is coupled to the downstream of a light chain gene of an antibody through an IRES sequence; the mouse glutamine synthetase mGS is coupled to the downstream of the puromycin resistance gene PuroR through an E2A polypeptide; and in the expression cassette II, the dihydrofolate reductase gene DHFR is coupled to the downstream of a heavy chain gene of the antibody through an IRES sequence. According to the antibody expression vector with the three selection markers, a PuroR gene and an mGS gene are linked to a light chain of the antibody, a DHFR gene is linked to a heavy chain of the antibody, and during selection, the expression balance of the light chain and the heavy chain is controlled by controlling the concentrations of MTX and MSX, so that the quality of a target antibody can be improved, a fragmented antibody or a polymer antibody is avoided, and the yield of the target antibody can be improved.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to an antibody expression vector with three screening markers, its construction method and application. Background technique [0002] Antibody drugs are the mainstream of biomedicine development today. To achieve large-scale production of antibody drugs, the first step must be to construct stable cell lines that efficiently express target antibodies. Among them, the antibody expression vector is the key substance for constructing a stable cell line that efficiently expresses the target antibody. [0003] Dihydrofolate reductase (DHFR) and glutamine synthetase (GS) are key substances in the metabolic pathway of cell growth, providing carbon and nitrogen sources for cell proliferation, respectively. When the dihydrofolate reductase (DHFR) in the cell genome is deleted or inactivated (it may also be inactivated by gene knockout), and the medium lacks a salvage synthesis pathway for carbon...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to solve the problems that the existing gene screening antibody expression vectors described in the background technology cannot balance the expression balance of the antibody light chain

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