CN113121688A

CN113121688A - Protein expression method

Info

Publication number: CN113121688A
Application number: CN202010000237.5A
Authority: CN
Inventors: 侯盛; 郭怀祖; 聂丽; 戴建新; 寇庚; 徐进; 郭清城; 张存超; 黄卫红
Original assignee: Shanghai Maitai Junao Biotechnology Co ltd; Shanghai Biomabs Pharmaceuticals Co Ltd
Current assignee: Shanghai Maitai Junao Biotechnology Co ltd; Shanghai Biomabs Pharmaceuticals Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-16
Also published as: CN113121701A; CN113122493A; CN113121687A; CN113122598A

Abstract

The invention provides a protein expression method, which uses a serum-free animal-origin-free culture medium, adopts a basic culture medium and a supplementary culture medium to carry out large-scale production expression of protein medicines, wherein the basic culture medium is suitable for cell amplification and perfusion culture, the supplementary culture medium is suitable for supplementary batch culture, and the protein medicines expressed by the method do not contain non-human-origin glycosylation.

Description

Protein expression method

Technical Field

The invention is a divisional application with the original application number of 2019114049586.

The invention belongs to the technical field of biology, and particularly relates to a protein expression method, more particularly to a CHO cell expression method of a protein drug, wherein the expressed protein drug does not contain non-human glycosylation.

Background

Among the post-translational modifications of proteins, glycosylation modifications are one of the most important and complex modifications, and are also one of the key attributes for evaluating the quality of protein-based drugs, such as antibody drugs.

The functional realization of protein drugs is closely related to glycosylation modification, and the glycosylation modification can influence the performance of the protein drugs, such as conformation, stability, solubility, pharmacokinetics, activity, immunogenicity and the like.

According to the glycosylation modification site, the glycosylation can be divided into N-glycosylation and O-glycosylation, the N-glycosylation is positioned at Asn-297, and N-acetylglucosamine in oligosaccharide is connected with amide nitrogen on asparagine residue to modify protein; the O-glycosylation modifies the protein by linking the N-acetylgalactosamine in the oligosaccharide to the hydroxyl group on the serine or threonine residue.

Glycosylation at the N-position of immunoglobulins expressed by animal cell expression systems is the most common glycosylation modification, and the glycosylation modification site is located at the Fc-terminus of antibodies, and can be classified into complex, hybrid and high mannose types according to the structure of the terminal. The glycosylation of the complex type takes fucose (Fuc) as a core, and N-acetylglucosamine (N-GlcNAc) is divided into two branches with equal length, and mannose (Man), galactose (Gal) and sialic acid (Sia) are accompanied on the branches, so that the N-position glycosylation of the Fc end of the antibody is formed. Antibody glycosylation modification patterns can be classified into G0F, G1F, G2F, G1FS, G2S1F, G2S2F, G0, G1, G2 (Fcglycans of therapeutic antibodies as critical quality antigens) depending on the monosaccharides in the two branches.

Different glycosylation modifications have different effects on the stability and half-life, safety and bioactivity of proteinaceous drugs. Glycosylation modification can increase the stability and solubility of protein drugs. However, the existence of glycosylation also affects the safety of protein drugs, and the existence of glycosylation of protein drugs affects the immunogenicity of the protein drugs during administration and also affects the pharmacokinetics and pharmacodynamics of the protein drugs; the glycosylation site of antibody drugs is often also the binding site of antibody Fc receptor (ADCC mechanism) and C1q (CDC mechanism), and also affects the biological activity of antibodies (engineered therapeutic antibodies with improved effector functions).

In the case of monoclonal antibodies, the sugar chain structure formed by glycosylation modification can maintain the spatial conformation of the antibody and stabilize the structure of the antibody, the stability of the antibody to heat after deglycosylation is greatly reduced, and the sugar chain structure can also protect the antibody from being hydrolyzed by certain proteases. The special glycoform in the sugar chain is also closely related to immune corresponding functions, and the glycoform is not biosynthesized in human body, and the glycosylation of the non-human source has certain immunogenicity and can accelerate the plasma elimination of the monoclonal antibody.

Sialylation in glycosylation two main types exist in mammalian cell expression systems, N-acetylneuraminic acid (Neu 5Ac, NANA), N-hydroxyethylneuraminic acid (Neu 5Gc, NGNA). Normally, the sialylation pattern contained in human IgG is Neu5Ac (NANA), while the sialylation pattern contained in mouse IgG is Neu5Gc (NGNA).

The glycosylation structure of Gal- α (1, 3) -Gal (α -Gal) is also produced in mammalian cell expression systems used for large scale production of proteins, α -Gal (α -galactose) is a non-human glycan that is very immunogenic and can trigger tissue rejection in xenotransplantation, NK cells can directly recognize this glycan, and treatment with monoclonal antibodies containing α -Gal glycan structures can cause severe hypersensitivity reactions if high levels of anti- α -Gal IgE antibodies are present.

At present, the large-scale production of the existing protein medicines mostly adopts animal cell culture, and uses animal cells to culture monoclonal antibodies, immune regulatory factors, specific tumor antigens and various gene recombinant protein medicines in a large scale. Compared with microorganisms, the animal cells have the function of post-transcriptional modification, and can express and produce various high-quality protein medicines more efficiently.

Chinese Hamster Ovary (CHO) cells are common culture host cells in large-scale production of protein medicines, a CHO cell expression system can express protein medicines with similar structures to human protein, the glycosylation mechanism of the CHO cells is similar to the glycosylation mechanism of human, but the expression of the CHO cells still has non-human glycosylation expression, and the non-human glycosylation can cause the expressed protein medicines to generate immunogenicity, generate side effects on the application of the protein medicines and influence the therapeutic effect of the expressed protein medicines.

Disclosure of Invention

In order to solve the problems, the invention provides a protein expression method, and more particularly discloses a CHO cell expression method of a protein drug, and the protein drug expressed by the method does not contain non-human glycosylation.

According to the invention, CHOM series serum-free animal-origin-free culture medium sold by Shanghai Mitai Junao biotechnology limited is adopted, and according to different culture modes, a basic culture medium and a supplement culture medium are used for large-scale production expression of protein medicines, wherein the basic culture medium is suitable for cell amplification and perfusion culture, and the supplement culture medium is suitable for supplement batch culture.

The CHOM-B series are serum-free, protein-free and animal-derived component-free culture media, and are specially applied to long-term suspension culture of recombinant protein CHO cells such as expression antibodies. Since it does not contain L-glutamine, it is particularly suitable for use in combination with a Glutamine Synthetase (GS) screening system. Wherein, CHOM-B01, CHOM-B02 and CHOM-B03 are chemically defined media. CHOM-B09 is an animal origin-free medium, free of L-glutamine, for CHO cell clone formation and growth.

The CHOM-S series is a supplement culture medium which is customized for the CHOM-B series and is applied to the late-stage addition of batch culture of recombinant protein CHO cells such as expression antibody and the like. The series of supplements do not contain animal-derived components and protein hydrolysates, have limited chemical components, and facilitate subsequent purification and protein structure analysis while improving the protein yield.

TABLE 1 product introduction for CHOM series of media

The invention provides a protein expression method, and a protein drug expressed by the method does not contain non-human glycosylation.

A method for expressing a protein, the method comprising an expansion and perfusion culture stage of an expression host cell, wherein the cell is cultured in a CHOM-B series medium, and a supplementary culture stage wherein the cell is cultured in a CHOM-S series medium.

In a preferred embodiment, the culture is carried out in a combined culture medium of the CHOM-B series in the cell expansion and perfusion stage and in a combined culture medium of the CHOM-S series in the supplementary culture stage.

The combined culture medium of the cell expansion and perfusion culture stage in the method is a combination of CHOM-B01 and CHOM-B02, or a combination of CHOM-B01 and CHOM-B03, or a combination of CHOM-B01, CHOM-B02 and CHOM-B03, preferably CHOM-B01: the CHOM-B02 is 1: 1-1: 5, CHOM-B01: the CHOM-B03 is 1: 1-1: 0.1.

The combined culture medium used in the supplementary culture stage in the above method is a combination of CHOM-S01 and CHOM-S03, or a combination of CHOM-S01 and CHOM-S04, or a combination of CHOM-S01, CHOM-S03 and CHOM-S04, preferably CHOM-S01: the CHOM-S03 is 1: 1-1: 0.3, CHOM-S01: the CHOM-S04 is 1: 1-1: 7.

The basic culture medium and the supplementary culture medium are used for culturing and expressing CHO cells, protein medicines are produced in a large scale, and parameters of large-scale production expression are adjusted according to different target proteins to be expressed.

Cell expansion and perfusion culture stage: the temperature is 30-39 ℃; the pH value of a basic culture medium is 6.6-7.1, and the pH value is adjusted by carbon dioxide and sodium carbonate solution; the dissolved oxygen is 30% -60%; ventilating: surface layer air, deep layer microbubble aeration including air, oxygen and carbon dioxide; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm.

And (3) a supplementary culture stage: detecting cell density in cell amplification and perfusion culture stages, reducing the temperature to 32-34 ℃ according to the cell density on the 2 nd-4 th day of culture, adding a supplementary culture medium, performing supplementary culture, wherein the amount of the supplementary culture medium added every day is 1-5% of the volume of an upper tank, stopping culture after 8-18 days of supplementary culture, collecting cell culture solution, removing cells and fragments through deep filtration and clarification, reducing the biological load through primary membrane filtration, obtaining culture supernatant containing target protein, separating and purifying to obtain the target protein, wherein the protein does not contain non-human glycosylation.

The expression method of the protein is used for culturing and expressing biological products such as monoclonal antibodies, bifunctional fusion proteins and the like. The biological product expressed by the expression method of the protein comprises Pan-P, anti-PD-L1 antibody, anti-PD-1 antibody and PD-L1/CD47 bifunctional fusion protein.

A method for preparing an anti-EGFR antibody is characterized in that a CHO host cell containing a Pan-P gene sequence of the anti-EGFR antibody is cultured and expressed by using a serum-free animal-derived component-free basal medium and a supplement medium, wherein the basal medium is a CHOM-B series combined medium, and the supplement medium is a CHOM-S series combined medium. Preferred conditions for the perfusion culture stage are: the temperature is 35.5-36.5 ℃; the pH value of the basic culture medium is 6.6-6.8; the dissolved oxygen is 30% -40%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm. And (3) reducing the temperature to 33 ℃ and the pH value to 7.0-7.1 in 2-4 days of perfusion culture, adding a supplement culture medium for supplement culture, wherein the amount of the supplement culture medium added every day is 1-5% of the volume of the upper tank, and performing low-temperature supplement culture for 8-10 days. The basic culture medium is CHOM-B01: the CHOM-B02 is 1: 1-1: 3. The supplement culture medium is CHOM-S01: the CHOM-S03 is 1: 1-1: 0.3.

The method for preparing the anti-PD-L1 antibody is characterized in that a serum-free animal-derived-component-free basal medium and a supplement medium are used for culturing and expressing CHO host cells containing anti-PD-L1 antibody gene sequences, wherein the basal medium is a CHOM-B series combined medium, and the supplement medium is a CHOM-S series combined medium. Preferred conditions for the perfusion culture stage are: the temperature is 35.5-36.5 ℃; the pH value of the basic culture medium is 6.8-6.9; the dissolved oxygen is 35% -45%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm. And (3) reducing the temperature to 32.5-33.5 ℃ and the pH to 7.1-7.2 in 2-4 days of perfusion culture, adding a supplement culture medium for supplement culture, wherein the amount of the supplement culture medium added per day is 1-5% of the upper perfusion volume, and performing low-temperature supplement culture for 8-10 days. The basic culture medium is CHOM-B01: the CHOM-B02 is 1: 1-1: 3, and the supplementary culture medium is CHOM-S01: the CHOM-S04 is 1: 1-1: 4.

The preparation method of the anti-PD-1 antibody is characterized in that a CHO host cell containing an anti-PD-1 antibody gene sequence is cultured and expressed by using a serum-free animal-derived component-free basal medium and a supplement medium, wherein the basal medium is a CHOM-B series combined medium, and the supplement medium is a CHOM-S series combined medium. Preferred conditions for the perfusion culture stage are: the temperature is 36.5-37.5 ℃; the pH value of the basic culture medium is 6.9-7.0; the dissolved oxygen is 40% -50%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm. And (3) reducing the temperature to 33 ℃ and the pH value to 7.0-7.1 in 2-4 days of perfusion culture, adding a supplement culture medium for supplement culture, wherein the amount of the supplement culture medium added every day is 1-5% of the volume of the upper tank, and performing low-temperature supplement culture for 10-12 days. The basic culture medium is CHOM-B01: the CHOM-B03 is 1: 1-1: 0.1, and the supplementary culture medium is CHOM-S01: the CHOM-S04 is 1: 1-1: 4.

A preparation method of an anti-PD-L1/CD 47 bifunctional fusion protein is characterized in that a serum-free basic culture medium without animal-derived components and a supplement culture medium are used for culturing and expressing CHO host cells containing anti-PD-L1/CD 47 bifunctional fusion protein gene sequences, wherein the basic culture medium is a CHOM-B series combined culture medium, and the supplement culture medium is a CHOM-S series combined culture medium. Preferred conditions for the perfusion culture stage are: the temperature is 36-37 ℃; the pH value of the basic culture medium is 6.9-7.0; the dissolved oxygen is 45% -55%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm. And (3) reducing the temperature to 32.5-33.5 ℃ and the pH to 7.0-7.1 in 2-4 days of perfusion culture, adding a supplement culture medium for supplement culture, wherein the amount of the supplement culture medium added per day is 1-5% of the upper perfusion volume, and performing low-temperature supplement culture for 8-10 days. The basic culture medium is CHOM-B01: the CHOM-B03 is 1: 1-1: 0.5, and the supplementary culture medium is CHOM-S01: the CHOM-S04 is 1: 1-1: 4.

Drawings

FIG. 1, Pan-P mass spectrometric profile (without non-human glycosylation);

FIG. 2, Mass Spectrometry detection profile (without non-human glycosylation) of anti-PD-L1 antibody;

FIG. 3, Mass Spectrometry detection profile of anti-PD-1 antibody (without non-human glycosylation);

FIG. 4, mass spectrometric detection profile of PD-L1/CD47 bifunctional fusion proteins (without non-human glycosylation).

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Example 1 screening of culture Medium types

The method is characterized by purchasing CHOM-B series products and CHOM-S series products without serum, animal protein and animal origin components from Shanghai Mitaojuno biotechnology limited, and selecting CHOM-B01, CHOM-B02, CHOM-B03, CHOM-S01, CHOM-S03 and CHOM-S04 products.

The basal medium and the supplement medium were further selected based on the results of the previous experiments using the CHOM-B series medium and the CHOM-S series medium. According to the types of the basic culture medium and the supplementary culture medium and the proportion of each component, the basic culture medium is divided into CHOM-B01: CHOM-B02 of 1:1, 1:3 and 1:5, the CHOM-B01: CHOM-B03 of 1:0.1, 1:0.5 and 1:1, and the supplementary culture medium is divided into CHOM-S01: CHOM-S03 of 1:0.3, 1:0.6 and 1:1, and the CHOM-S01: CHOM-S04 of 1:1, 1:4 and 1: 7.

The results of the culture of CHO cells using the culture media of the above different ratios, which were subjected to the basal culture and the supplementary culture, were shown in tables 1 and 2, in which the cell viability and the cell density were measured during the culture.

TABLE 1 cell viability (%) assay results for CHO cells cultured in media of different proportions

TABLE 2 cell density (. times.10) of CHO cells cultured in different ratios of medium⁶cell/ml) test results

After multi-round screening of the components of the culture medium, selecting a basic culture medium according to the test result as follows: CHOM-B01, CHOM-B02 is 1:3, CHOM-B01, CHOM-B03 is 1: 1.

After multi-round screening of the components of the culture medium, the supplementary culture medium is selected according to the test result as follows: the CHOM-S01: CHOM-S03 is 1:0.3, and CHOM-S01: CHOM-S04 is 1: 4.

Example 2 protein expression method

The basal medium and the supplementary medium CHOM-B01: CHOM-B02 are 1:3, CHOM-B01: CHOM-B03 are 1:1, the supplementary medium CHOM-S01: CHOM-S03 is 1:0.3, CHOM-S01: CHOM-S04 are 1:4 after screening in example 1 are selected, and the target protein is produced and expressed in a large scale.

The large-scale production and expression of proteins mainly comprises a cell expansion and perfusion culture stage and a supplementary culture stage.

1. Cell expansion:

1) and recovering the working cells: taking 1 working cell out of the working cell bank, placing in a water bath at 37 ℃ and thawing; 5ml of recovery culture solution is used, the solution is changed through centrifugation, the solution is inoculated into a shake flask of 100 ml-150 ml, and 10 ml-15 ml of basic culture medium is added into the shake flask; and placing the shake flask in a carbon dioxide shaking table for shaking culture at the temperature of 37 ℃ and the speed of 70-170 rpm, wherein the concentration of carbon dioxide is 2-10%.

2) First-stage seeds: the parameters of the culture medium and the carbon dioxide shaking table used in the first-stage seed amplification are the same as those used in the recovery. And (3) gradually amplifying the recovered cells by using shake flask culture, determining the culture volume and the seed cell density according to the culture scale, wherein the cell survival rate is more than 90%, and partially or completely inoculating the cell suspension in the amplified shake flask to the second-stage seeds according to the density determination after inoculation for further culture.

3) And secondary seeds: installing a secondary reactor, injecting a basic culture medium, stably setting the temperature to be 35-39 ℃, setting the pH value to be 6.6-7.1, regulating the pH value by using carbon dioxide and a sodium carbonate solution, controlling the swing speed to be 20-30 rpm, shaking and uniformly mixing waves, setting the surface aeration flow to be 0.1-0.8L/min, setting the dissolved oxygen to be 30-60%, and supplementing glucose to 3-5 g/L every day.

The density of viable cells after inoculation is not less than 0.3 × 10⁶And (4) cell/ml, wherein the inoculation ratio is 1: 2-1: 8, and the cells are cultured until the cell density and the survival rate meet the inoculation requirements. And determining the culture volume and the seed cell density according to the culture scale, wherein the cell survival rate is required to be more than 90%, the microscopic examination is not abnormal, and the next stage is transferred according to the proportion of 1: 2-1: 8.

4) And third-level seeds: installing a three-stage reactor, injecting a basic culture medium, stably setting the temperature to be 35-39 ℃, the pH value to be 6.6-7.1, regulating the pH value by using carbon dioxide and sodium carbonate solution, controlling the swing speed to be 15-25 rpm, shaking and uniformly mixing waves, setting the surface aeration flow to be 0.5-4L/min, setting the dissolved oxygen to be 40%, and setting the density of the inoculated living cells to be not less than 0.3 multiplied by 10⁶cell/ml, the inoculation ratio is 1: 2-1: 8, and the batch culture is supplemented until the cell density and the survival rate meet the inoculation requirements. Determining the culture volume and the seed cell density according to the culture scale, wherein the cell survival rate is more than 80%, and transferring the seeds to production culture according to the proportion of 1: 2-1: 8.

2. Perfusion culture:

transferring the cells after the cell amplification into a 500L cell culture reactor to make the initial cells denseDegree of not less than 0.3X 10⁶cell/ml. The temperature is 35-39 ℃, and the temperature control range is adjusted according to the requirement of the culture process; pH of 6.6-7.2 with CO₂Regulating pH with sodium carbonate solution; stirring at 80-150 rpm; surface layer air, deep layer microbubble ventilation including air, oxygen and carbon dioxide; 30-60% of dissolved oxygen; supplementing 3-5 g/L of glucose every day.

3. And (3) supplementary culture:

after the perfusion culture is carried out for 48-72 hours, adjusting the temperature of a cell culture reactor to 32-34 ℃, adjusting the pH to 7.0-7.3, and adding a supplementary culture medium and a glucose solution; adding a supplementary culture medium according to the cell density until harvesting, wherein the addition amount is 1-5% of the initial tank loading volume every day, and culturing for 6-16 days at a low temperature.

The production culture period is determined according to different target proteins, the production culture period is generally 8-18 days, in the normal culture period, the expression and quality of the target proteins meet the requirements, namely the culture of the protein expression can be stopped, and the subsequent treatment procedure is carried out. And clarifying the cell culture solution by deep filtration to remove cells and fragments thereof, reducing the biological load by primary membrane filtration to obtain a culture supernatant containing the target protein, and purifying the culture supernatant to obtain the target protein.

Example 3 expression of Pan-P antibody

Using different basic and supplementary media as described above, the Pan-P antibody was cultured and expressed in CHO cells, and the glycoform of the Pan-P antibody obtained by the culture and expression was detected.

Pan-P is a fully human epidermal growth factor receptor EGFR monoclonal antibody disclosed in patent application No. CN201410724477.4, an expression vector containing a Pan-P gene sequence is obtained according to the method disclosed in patent No. CN201410724477.4, and the Pan-P gene sequence is transferred into CHO cells for culture and expression.

The large-scale production of the Pan-P antibody is realized by culturing and expressing CHO host cells containing Pan-P antibody gene sequences by adopting a basic culture and supplementary culture method. Wherein the basic culture medium is prepared according to the proportion of CHOM-B01: CHOM-B02 is 1:3 or CHOM-B01: CHOM-B03 is 1: 1; the supplement culture medium is as follows: the CHOM-S01: CHOM-S03 is 1:0.3 or CHOM-S01: CHOM-S04 is 1: 4.

Preferably, the basic culture medium CHOM-B01: CHOM-B02 is 1:3, and the supplementary culture medium CHOM-S01: CHOM-S03 is 1: 0.3.

Cell expansion: a) and (3) recovering working cells: putting the working cells in water bath at 37 ℃ for thawing; using 5ml of basic culture medium, carrying out centrifugation and liquid change, inoculating the medium into a 100 ml-150 ml shake flask, and adding 10-15 ml of basic culture medium into the flask; and placing the shake flask in a carbon dioxide shaking table for shaking culture at the temperature of 37 ℃ and the speed of 70-170 rpm, wherein the concentration of carbon dioxide is 2-10%. b) Seed amplification: injecting a basic culture medium, setting the temperature to be 35-39 ℃, regulating the pH value to be 6.6-7.1, regulating the pH value by using carbon dioxide and sodium carbonate solution, controlling the swing speed to be 25-30 rpm, shaking and uniformly mixing waves, setting the surface aeration flow to be 0.1-0.8L/min, setting the dissolved oxygen to be 30-60%, and supplementing glucose to 3-5 g/L every day. The density of viable cells after inoculation is not less than 0.3 × 10⁶cell/ml, the inoculation ratio is 1: 2-1: 8, the cell viability is required to be more than 90%, no abnormality is caused by microscopic examination, and the next stage is transferred according to the ratio of 1: 2-1: 8.

Perfusion culture: transferring the cells after the cell amplification into a 500L cell culture reactor to make the initial cell density not less than 0.3 × 10⁶cell/ml. The temperature is 35-39 ℃, the temperature control range is adjusted according to the requirement of the culture process, and the optimal temperature is 35.5-36.5 ℃; adjusting pH to 6.6-7.2, preferably pH 6.6-6.8, with CO₂Regulating pH with sodium carbonate solution; stirring at 80-150 rpm; surface layer air, deep layer microbubble ventilation including air, oxygen and carbon dioxide; 30-60% of dissolved oxygen, preferably 30-40%; supplementing 3-5 g/L of glucose every day.

And (3) supplementary culture: after the perfusion culture is carried out for 48-72 hours, adjusting the temperature of a cell culture reactor to 32-34 ℃, preferably 33 ℃, adjusting the pH to 7.0-7.3, preferably 7.0-7.1, and adding a supplementary culture medium and a glucose solution; adding a supplementary culture medium according to the cell density until harvesting, wherein the daily addition amount is 1-5% of the initial tank feeding volume, and culturing for 8-10 days at a low temperature.

After 8-10 days of culture and expression, collecting cell culture fluid, clarifying the cell culture fluid by deep filtration to remove cells and fragments thereof, reducing the biological load by primary membrane filtration to obtain a culture supernatant containing the Pan-P antibody, purifying the culture supernatant to obtain the Pan-P antibody, and carrying out mass spectrum glycoform detection on the obtained Pan-P antibody, wherein the result is shown in figure 1, and the sialylation type contained in mouse-free IgG of the Pan-P antibody obtained by the culture method is Neu5Gc (NGNA) and does not contain alpha-1 and alpha-3 galactose, which can be obviously known from a detected mass spectrum by using the basic culture medium and the supplementary culture medium.

Example 5 expression of the PD-L1 monoclonal antibody

Using the different basic and supplementary culture media, the PD-L1 monoclonal antibody is taken as an example, CHO host cells containing the PD-L1 monoclonal antibody gene are cultured and expressed, and the glycoform of the PD-L1 monoclonal antibody which is cultured and expressed is detected.

The PD-L1 monoclonal antibody is a PD-L1 monoclonal antibody disclosed in the patent application number CN201811035690.9, an expression vector containing the gene sequence of the PD-L1 monoclonal antibody is obtained according to the method disclosed in the patent application number CN201811035690.9, and the expression vector is transferred into CHO host cells for culture expression.

The large-scale production of the expression PD-L1 monoclonal antibody adopts the methods of basic culture and supplementary culture to culture and express the CHO cell containing the gene sequence of the PD-L1 monoclonal antibody. Wherein the basic culture medium is prepared according to the proportion of CHOM-B01: CHOM-B02 is 1:3 or CHOM-B01: CHOM-B03 is 1: 1; the supplement culture medium is as follows: the CHOM-S01: CHOM-S03 is 1:0.3 or CHOM-S01: CHOM-S04 is 1: 4.

Preferably, the basic culture medium CHOM-B01: CHOM-B02 is 1:3, and the supplementary culture medium CHOM-S01: CHOM-S04 is 1: 4.

Cell expansion: a) and (3) recovering working cells: putting the working cells in water bath at 37 ℃ for thawing; using 5ml of basic culture medium, carrying out centrifugation and liquid change, inoculating the medium into a 100 ml-150 ml shake flask, and adding 10-15 ml of basic culture medium into the flask; and placing the shake flask in a carbon dioxide shaking table for shaking culture at the temperature of 37 ℃ and the speed of 70-170 rpm, wherein the concentration of carbon dioxide is 2-10%. b) Seed amplification: injecting a basic culture medium, setting the temperature to be 35-39 ℃, regulating the pH value to be 6.6-7.1, regulating the pH value by using carbon dioxide and sodium carbonate solution, controlling the swing speed to be 25-30 rpm, shaking and uniformly mixing waves, and ensuring that the surface aeration flow is 0.1-0.8L/min, dissolved oxygen is set to be 30-60%, and glucose is supplemented to 3-5 g/L every day. The density of viable cells after inoculation is not less than 0.3 × 10⁶cell/ml, the inoculation ratio is 1: 2-1: 8, the cell viability is required to be more than 90%, no abnormality is caused by microscopic examination, and the next stage is transferred according to the ratio of 1: 2-1: 8.

Perfusion culture: transferring the cells after the cell amplification into a 500L cell culture reactor to make the initial cell density not less than 0.3 × 10⁶cell/ml. The temperature is 35-39 ℃, the temperature control range is adjusted according to the requirement of the culture process, and the optimal temperature is 35.5-36.5 ℃; pH 6.6-7.2, preferably pH 6.8-6.9, with CO₂Regulating pH with sodium carbonate solution; stirring at 80-150 rpm; surface layer air, deep layer microbubble ventilation including air, oxygen and carbon dioxide; 30-60% of dissolved oxygen, preferably 35-45%; supplementing 3-5 g/L of glucose every day.

And (3) supplementary culture: after the perfusion culture is carried out for 48-72 hours, adjusting the temperature of a cell culture reactor to 32-34 ℃, preferably 32.5-33.5 ℃, adjusting the pH to 7.0-7.3, preferably 7.1-7.2, and adding a supplementary culture medium and a glucose solution; adding a supplementary culture medium according to the cell density until harvesting, wherein the daily addition amount is 1-5% of the initial tank feeding volume, and culturing for 8-10 days at a low temperature.

After 8-10 days of culture expression, collecting cell culture fluid, clarifying the cell culture fluid by deep filtration to remove cells and fragments thereof, reducing the biological load by primary membrane filtration to obtain culture supernatant containing the PD-L1 monoclonal antibody, purifying the culture supernatant to obtain the PD-L1 monoclonal antibody, and performing mass spectrometric glycoform detection on the obtained PD-L1 monoclonal antibody, wherein the result is shown in figure 2, and the sialylation type contained in mouse IgG, which is not contained in the PD-L1 monoclonal antibody cultured by the culture method, is Neu5Gc (NGNA) and does not contain alpha-1, 3 galactose, can be obviously known from a detected mass spectrogram.

Example 6 expression of PD-1 monoclonal antibody

Using the different basic and supplementary culture media described above, the PD-1 monoclonal antibody was used as an example, CHO cell culture and expression were performed, and the glycoform of the PD-1 monoclonal antibody expressed by the culture was detected.

The PD-1 monoclonal antibody is the PD-1 monoclonal antibody disclosed in the patent application number CN201680069571.8, an expression vector containing the gene sequence of the PD-1 monoclonal antibody is obtained according to the method disclosed in the patent CN201980069571.8, and the expression vector is transferred into a CHO host cell for culture expression.

The large-scale production of expression PD-1 monoclonal antibody adopts the methods of basic culture and supplementary culture to culture and express CHO cells containing PD-1 monoclonal antibody gene sequence. Wherein the basic culture medium is prepared according to the proportion of CHOM-B01: CHOM-B02 is 1:3 or CHOM-B01: CHOM-B03 is 1: 1; the supplement culture medium is as follows: the CHOM-S01: CHOM-S03 is 1:0.3 or CHOM-S01: CHOM-S04 is 1: 4.

Preferably, the basic culture medium CHOM-B01: CHOM-B03 is 1:1, and the supplementary culture medium CHOM-S01: CHOM-S04 is 1: 4.

Perfusion culture: transferring the cells after the cell amplification into a 500L cell culture reactor to make the initial cell density not less than 0.3 × 10⁶cell/ml. The temperature is 35-39 ℃, the temperature control range is adjusted according to the requirement of the culture process, and the preferable temperature is 36.5-37.5 ℃; pH 6.6-7.2, preferably pH 6.9-7.0, with CO₂Regulating pH with sodium carbonate solution; stirring at 80-150 rpm; surface air and deep microbubble including air, oxygen and carbon dioxide(ii) a 30-60% of dissolved oxygen, preferably 40-50%; supplementing 3-5 g/L of glucose every day.

And (3) supplementary culture: after the perfusion culture is carried out for 48-72 hours, adjusting the temperature of a cell culture reactor to 32-34 ℃, and preferably 33 ℃; adjusting the pH value to 7.0-7.3, preferably to 7.0-7.1; adding a supplementary culture medium and a glucose solution; adding a supplementary culture medium according to the cell density until harvesting, wherein the daily addition amount is 1-5% of the initial tank feeding volume, and culturing for 10-12 days at a low temperature.

After 10-12 days of culture expression, collecting cell culture fluid, clarifying the cell culture fluid through depth filtration to remove cells and fragments thereof, reducing the biological load through primary membrane filtration to obtain culture supernatant containing the PD-1 monoclonal antibody, purifying the culture supernatant to obtain the PD-1 monoclonal antibody, and performing mass spectrometry glycoform detection on the obtained PD-1 monoclonal antibody, wherein the result is shown in figure 3, and the result is obvious from a detected mass spectrogram, and the PD-1 monoclonal antibody obtained by the culture method does not contain mouse IgG, contains Neu5Gc (NGNA) and does not contain alpha-1 and alpha-3 galactose by using the basic culture medium and the supplementary culture medium.

Example 7 expression of PD-L1/CD47 bifunctional fusion proteins

Taking PD-L1/CD47 bifunctional fusion protein as an example, CHO cell culture and expression are carried out on the fusion protein by using different basic culture media and supplementary culture media, and the glycoform of the PD-L1/CD47 bifunctional fusion protein expressed by the culture is detected.

The PD-L1/CD47 bifunctional fusion protein is PD-L1/CD47 bifunctional fusion protein disclosed in the patent application number CN201610372954.4, an expression vector containing a PD-L1/CD47 bifunctional fusion protein gene sequence is obtained according to the method disclosed in the patent CN201610372954.4, and the expression vector is transferred into a CHO host cell for culture and expression.

The PD-L1/CD47 bifunctional fusion protein is produced in a large scale, and CHO cells containing PD-L1/CD47 bifunctional fusion protein gene sequences are cultured and expressed by adopting a basic culture and supplementary culture method. Wherein the basic culture medium is prepared according to the proportion of CHOM-B01: CHOM-B02 is 1:3 or CHOM-B01: CHOM-B03 is 1: 0.5; the supplement culture medium is as follows: the CHOM-S01: CHOM-S03 is 1:0.3 or CHOM-S01: CHOM-S04 is 1: 4.

Preferably, the basic culture medium CHOM-B01: CHOM-B03 is 1:0.5, and the supplementary culture medium CHOM-S01: CHOM-S04 is 1: 4.

Perfusion culture: transferring the cells after the cell amplification into a 500L cell culture reactor to make the initial cell density not less than 0.3 × 10⁶cell/ml. The temperature is 35-39 ℃, the temperature control range is adjusted according to the requirement of the culture process, and the preferable temperature is 36-37 ℃; pH 6.6-7.2, preferably pH 6.9-7.0, with CO₂Regulating pH with sodium carbonate solution; stirring at 80-150 rpm; surface layer air, deep layer microbubble ventilation including air, oxygen and carbon dioxide; 30-60% of dissolved oxygen, preferably 45-55%; supplementing 3-5 g/L of glucose every day.

And (3) supplementary culture: after the perfusion culture is carried out for 48-72 hours, adjusting the temperature of a cell culture reactor to 32-34 ℃, and preferably, the temperature is 32.5-33.5 ℃; adjusting the pH value to 7.0-7.3, preferably to 7.0-7.1; adding a supplementary culture medium and a glucose solution; adding a supplementary culture medium according to the cell density until harvesting, wherein the daily addition amount is 1-5% of the initial tank feeding volume, and culturing for 8-10 days at a low temperature.

After 8-10 days of culture expression, collecting cell culture fluid, clarifying the cell culture fluid by deep filtration to remove cells and fragments thereof, reducing the biological load by primary membrane filtration to obtain culture supernatant containing the PD-L1/CD47 bifunctional fusion protein, purifying the culture supernatant to obtain the PD-L1/CD47 bifunctional fusion protein, and performing mass spectrum glycoform detection on the obtained PD-L1/CD47 bifunctional fusion protein, wherein the result is shown in figure 4, and the mass spectrum obtained by detection can be obviously known by using the basic culture medium and a supplementary culture medium, and the PD-L1/CD47 bifunctional fusion protein obtained by the culture method does not contain mouse IgG, contains the sialylation type Neu5Gc (NGNA) and does not contain alpha-1, 3 galactose.

Claims

1. The method for preparing the anti-PD-L1 antibody is characterized in that a serum-free animal-derived-component-free basal medium and a supplement medium are used for culturing and expressing CHO host cells containing anti-PD-L1 antibody gene sequences, wherein the basal medium is a CHOM-B series combined medium, and the supplement medium is a CHOM-S series combined medium.

2. The method for producing an anti-PD-L1 antibody according to claim 1, wherein the culture expression of CHO host cells in the method includes a cell expansion phase, a perfusion culture phase and a supplementary culture phase, wherein a basal medium is used in the cell expansion and perfusion culture phase, and a supplementary medium is used in the supplementary culture phase.

3. The method for producing an anti-PD-L1 antibody according to claim 2, wherein the CHO host cell perfusion culture stage conditions are: the temperature is 30-39 ℃; the pH value of the basic culture medium is 6.6-7.1; the dissolved oxygen is 30% -60%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm.

4. The method for producing an anti-PD-L1 antibody according to claim 3, wherein the CHO host cell perfusion culture stage conditions are: the temperature is 35.5-36.5 ℃; the pH value of the basic culture medium is 6.8-6.9; the dissolved oxygen is 35% -45%; supplementing 3-5 g/L of glucose every day; the stirring speed is 80-150 rpm.

5. The method of producing an anti-PD-L1 antibody according to claim 2, wherein the conditions of the CHO host cell supplementary culture stage are: and (3) reducing the temperature to 32-34 ℃ and the pH to 7.0-7.3 in 2-4 days of perfusion culture, adding a supplementary culture medium for supplementary culture, wherein the amount of the supplementary culture medium added every day is 1-5% of the volume of the upper tank, and the supplementary culture is carried out for 8-18 days.

6. The method of producing an anti-PD-L1 antibody according to claim 5, wherein the conditions of the CHO host cell supplementary culture stage are: and (3) reducing the temperature to 32.5-33.5 ℃ and the pH to 7.1-7.2 in 2-4 days of perfusion culture, adding a supplement culture medium for supplement culture, wherein the amount of the supplement culture medium added per day is 1-5% of the upper perfusion volume, and performing low-temperature supplement culture for 8-10 days.

7. The method for preparing anti-PD-L1 antibody according to claim 1-6, characterized in that the basic culture medium is the combination of CHOM-B01 and CHOM-B02, CHOM-B01 and CHOM-B03, CHOM-B01 and CHOM-B02 and CHOM-B03.

8. The method for preparing anti-PD-L1 antibody according to claim 7, wherein the basic culture medium is CHOM-B01: the CHOM-B02 is 1: 1-1: 5, CHOM-B01: the CHOM-B03 is 1: 1-1: 0.1.

9. The method for preparing anti-PD-L1 antibody according to claim 8, wherein the basic culture medium is CHOM-B01: the CHOM-B02 is 1: 1-1: 3.

10. The method of claim 1-6 for the preparation of an anti-PD-L1 antibody, wherein the supplemented medium is CHOM-S01 in combination with CHOM-S03, CHOM-S01 in combination with CHOM-S04, CHOM-S01 in combination with CHOM-S03 and CHOM-S04.

11. The method of claim 10, wherein the supplemented medium is CHOM-S01: the CHOM-S03 is 1: 1-1: 0.3, CHOM-S01: the CHOM-S04 is 1: 1-1: 7.

12. The method of claim 11, wherein the supplemented medium is CHOM-S01: the CHOM-S04 is 1: 1-1: 4.