CN103897064A

CN103897064A - Long-acting recombinant human chorionic gonadotrophin-Fc fusion protein

Info

Publication number: CN103897064A
Application number: CN201310617181.8A
Authority: CN
Inventors: 侯永敏; 李强; 徐桢琦; 吴茂柏; 张玉杰; 王安新
Original assignee: GUANGZHOU YOULIANKANG PHARMACEUTICAL TECHNOLOGY Co Ltd
Current assignee: Guangzhou best Biotechnology Co., Ltd.
Priority date: 2013-11-29
Filing date: 2013-11-29
Publication date: 2014-07-02
Anticipated expiration: 2033-11-29
Also published as: CN103897064B

Abstract

The invention discloses a recombinant human chorionic gonadotrophin-Fc fusion protein (HCG-Fc for short) and a preparation method thereof. The HCG-Fc protein is a dimerized fusion protein, and the amino acid sequence of the fusion protein sequentially comprises an HCG beta subunit, an HCG alpha subunit, a flexible peptide joint and a human IgG Fc mutant from an N end to a C end. Compared with the existing chorionic gonadotrophin, the fusion protein has longer in-vivo half life, higher bioavailability and lower side effect. The invention also relates to an application of a recombinant HCG-Fc fusion protein composition in preparation of medicaments for treating and/or preventing infertility.

Description

Long-acting recombinant human chorionic gonadotrophin fusion rotein

Technical field

The present invention relates to molecular biology and field of medicaments.More specifically, the present invention relates to long-acting recombinant human chorionic gonadotrophin fusion rotein, its preparation method and application.This fusion rotein Half-life in vivo significant prolongation, bioavailability significantly increases, and greatly reduces medication number of times and dosage, reduces side effect.

Background technology

Physex (Human chorionic gonadotrophin, be called for short HCG) be the conventional medicine main component in human reproduction field, be widely used in Obstetric and Gynecologic Department and sterility treatment, main application comprises brings out ovulation, promote sperm development, treatment dysfunctional uterine hemorrhage and habitual abortion, control premature labor, alleviates production pain etc.At present the HCG in China market is mainly the product extracting in pregnant woman urine, the defect such as have that virus is polluted, raw material sources are limited, collections is difficult, content is low and purge process is complicated, and the developed country such as American-European does not generally accept to urinate that product-derived goes on the market and sale.

Comparatively speaking, restructuring HCG is the product of producing by genetically engineered and mammaliancellculture, and it has advantages of that at aspects such as its purity, antigenicity, security, virus-free infections urine source HCG product is incomparable.HCG is a kind of glycosylated protein, and it is 50KD that SDS-PAGE detects its molecular weight.In addition, HCG is the glycosylated protein with two strands (α chain and β chain), and interchain connects with non covalent bond, the biological activity of the correct folding guarantee HCG of two chains.The normal combination that how to keep two chains in protein expression and purge process is a challenge.As a kind of medicine, guarantee its biological activity, necessary condition is to have correct three-dimensional structure and glycosylation modified.Have that to improve posttranslational modification function be the main cause that mammalian cell is selected as most of biological medicament protein expression hosts.Wherein, Chinese hamster ovary cell (Chinese Hamster Ovary Cell, be called for short CHO) be for the most successfully host cell of eukaryote exogenous gene expression, existing increasing pharmaceutical protein has obtained high efficient expression therein, and a lot of people are gone on the market with recombinant protein medicine.Compared with other expression system, this system has many advantages, as have a complete translation post-treatment process, comprise glycosylation, hydroxylation, make the external source eukaryotic gene product of expressing can keep its natural structure and activity, and expression product is secreted into outside born of the same parents, is conducive to the separation and purification of foreign protein.

Although the existing reconstituted drug HCG listing that utilizes Chinese hamster ovary celI to produce at present, but still there are the following problems: first, its transformation period is shorter, in order to reach effective result for the treatment of, needs frequent drug administration clinically, brings very big misery to patient.For example, when for induced ovulation, 1-2 HCG of patient's palpus intramuscular injection every day, needs injection continuously 5 days conventionally.This treatment plan is often with bad side effect, comprise nerve, internal secretion and immune stimulation and toxic side effect, and cause common complication as ovarian hyperstimulation syndrome, show as ovary increase, the increase of whole body capillary permeability and ascites and form, severe one can jeopardize patient's life.Secondly, the HCG expression amount of recombinating is at present low, and preparation process is complicated and production cost is huge.In addition, HCG is the glycosylated protein with two strands (α chain and β chain), and interchain connects with non covalent bond, the biological activity of the correct folding guarantee HCG of two chains.The normal combination that how to keep two chains in protein expression and purge process is a challenge.For the defect of existing restructuring HCG and like product, the present invention utilizes the novel restructuring HCG product of modern molecular biology technique, cells produce and protein purification process exploitation, with prolong half-life, raising bioavailability and raising restructuring HCG protein expression level, thereby reduce administration number of times and dosage, reduce side effect.

Summary of the invention

The present invention aims to provide a kind of recombinant human chorionic gonadotrophin fusion rotein (Human chorionic gonadotrophin-Fc fusion protein, be called for short HCG-Fc) and preparation method thereof and application, to solve the problem that HCG expression amount is low, purifying is difficult, Half-life in vivo is short of recombinating in prior art.

An object of the present invention is to provide restructuring HCG-Fc fusion rotein, this fusion rotein is dimerization fusion rotein, its aminoacid sequence holds C end to comprise successively HCG β subunit from N, HCG α subunit, peptide linker (Linker, be called for short L) and human IgG Fc variant (vIgG2Fc, vIgG4Fc and vIgG1Fc), as SEQ ID NO:2, (HCG β-HCG α-vIgG2Fc shown in 4 and 6, HCG β-HCG α-vIgG4Fc, HCG β-HCG α-vIgG1Fc aminoacid sequence), preferred aminoacid sequence is as SEQ ID NO:2 (HCG β-HCG α-vIgG2Fc), above-mentioned fusion rotein is referred to as HCG-Fc.

The aminoacid sequence of described HCG β subunit has been removed the 1-20 amino acids residue in complete HCG β subunit, and the aminoacid sequence of ripe HCG β subunit is as shown in SEQ ID NO:8.

The amino acid residue sequence of described HCG α subunit has been removed the 1-24 amino acids residue in complete HCG α subunit, and the aminoacid sequence of ripe HCG α subunit is as shown in SEQ IDNO:7.

Described peptide linker contains 2-20 amino-acid residue, and peptide linker contains two or more and be selected from the amino-acid residue of glycine, Serine, L-Ala and Threonine, preferred peptide linker aminoacid sequence is GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer.

Described human IgG Fc variant comprises: human IgG2's hinge region, CH2 and CH3 region that (1) contains Pro331Ser sudden change; (2) human IgG 4 hinge regions, CH2 and the CH3 region of containing Ser228Pro and Leu235Ala sudden change; (3) human IgG1's hinge region, CH2 and the CH3 region of containing Leu234Val, Leu235Ala and Pro331Ser sudden change.Preferred human IgG Fc variant is to contain human IgG2's hinge region, CH2 and CH3 region that Pro331Ser suddenlys change.

Below specifically introduce human IgG Fc variant of the present invention, peptide linker function:

IgG Fc variant

The immunoglobulin (Ig) of IgG class is rich in protein in human blood, and their transformation period can be up to 21 days, and Fc fragment be in IgG holder compared with long half-lift major cause, there is the effect of stabilize proteins simultaneously.

Fc is from the Fc region of immunoglobulin (Ig), and Fc has vital role in the immune defense of eliminating pathogen.The effector function of IgG is mediated by Fc, by two kinds of main mechanisms: the combination of (1) and cell surface Fc acceptor (Fc γ Rs), by antibody dependent cellular cytotoxicity (ADCC) approach digestion pathogenic agent, or the combination of the Clq of (2) and the first complement component Cl part, cause cytotoxicity (CDC) approach that depends on complement, thus cracking pathogenic agent.In four kinds of human IgG isotypes, IgG1 and IgG3 can be effectively in conjunction with Fc γ Rs.IgG4 with the binding affinity of Fc γ Rs than a low order of magnitude of IgG1 and IgG3, and the combination of IgG2 and Fc γ Rs low be difficult to measure.Human IgG1 and IgG3 can also be effectively in conjunction with Clq, and activating complement cascade reaction.Human IgG2 is fixing very weak to complement, and the extreme ability that lacks activating complement cascade of IgG4 performance.For medical use, the Fc region of restructuring dimerization albumen must not can mediate effector function and cracking or remove these cells.Therefore, the Fc region of HCG-Fc must be non-cracking performance, in conjunction with Fc γ Rs and Clq and aspect trigger effect subfunction, and preferably non-activity of Fc.Obviously, do not have a kind of natural IgG isotype to be applicable to producing HCG-L-Fc restructuring dimerization albumen.In order to obtain the Fc of non-cracking performance, must make some amino acid mutations in natural Fc region, to reduce its effector function.

By analyzing the aminoacid sequence of IgG isotype of different genera, finding that near Fc part CH2 region N-terminal is presented in the combination of IgG Fc and Fc γ Rs works, and is positioned near the CH2 region carboxyl terminal of human IgG and be bonded to pass part and parcel with Clq.The effector function causing in order to reduce the combination of Fc and Fc γ Rs and Clq, the present invention uses following human IgG Fc variant (Fig. 1): (1) IgG2Fc variant: human IgG2's hinge region, CH2 and the CH3 region of containing Pro331Ser sudden change; (2) IgG4Fc variant: human IgG 4 hinge regions, CH2 and the CH3 region of containing Ser228Pro and Leu235Ala sudden change; (3) IgG1Fc variant: human IgG1's hinge region, CH2 and the CH3 region of containing Leu234Val, Leu235Ala and Pro331Ser sudden change.Preferred human IgG Fc variant is to contain human IgG2's hinge region, CH2 and CH3 region that Pro331Ser suddenlys change.

Above-mentioned Fc variant shows much lower effector function than natural IgG2Fc, IgG4Fc and IgG1Fc, is more suitable for preparation restructuring HCG-Fc fusion rotein.

Peptide linker

The length of connection peptides is extremely important to the activity of restructuring dimerization albumen.Existing people has reported erythropoietin (EPO) derivative (as dipolymer), compared with EPO monomer, the restructuring dimerization albumen that contains 2 complete EPO regions (3 to 7 the amino acid peptide joints of being separated by) shows the activity weakening (referring to Qiu H etc., J Biol Chem, 273:11173-11176,1998).But in the time that the length of the interregional peptide linker of these two EPO is 17 amino acid, the in vitro and in vivo biological activity of dimer EPO molecule obviously improves (Sytkowski AJ etc., J Biol Chem, 274:24773-24778,1999; U.S. Patent No. 6,187,564).This possible explanation is the connection peptides increasing between restructuring dimerization albumen two portions, makes two portions of this molecule can exercise respectively its function (referring to Ashkenazi A etc., Curr Opin in Immunol, 9:195-200,1997).

The inventor is through long-term and deep research, and the hinge region peptide linker that has designed first a kind of uniqueness reduces space steric effect, can make the C end of HCG α chain and the restructuring dimerization albumen of Fc variant coupling, and there is soft peptide linker centre.This restructuring dimerization albumen not only can not cause the afunction of HCG, can maintain on the contrary, even improve the biological activity of HCG-Fc restructuring dimerization albumen.The amino acid residue sequence of preferred peptide joint is GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer.

Restructuring HCG-Fc fusion rotein of the present invention has following characteristics: this recombination fusion protein is dimerization fusion rotein, and its aminoacid sequence holds C end to comprise successively HCG β subunit, HCG α subunit, peptide linker and human IgG Fc variant from N.Human IgG Fc variant has the effect that extends Half-life in vivo and stabilize proteins, and Fc variant is non-cracking performance, can reduce the effector function of being combined with Fc γ Rs and Clq and trigger.Carry out the coupling of C end with the Fc variant of HCG α chain by soft peptide linker, can maintain, even improve the biological activity of restructuring HCG-Fc fusion rotein.

The present invention is connected to peptide linker and human IgG Fc variant (vIgG2Fc, vIgG4Fc or vIgG1Fc) in an orderly manner first in HCG and forms novel restructuring HCG-Fc fusion rotein.In this fusion rotein, the positional alignment of human IgG Fc variant and peptide linker can maintain the sterie configuration that HCG is correct, and do not affect its biological activity, and can the significant prolongation transformation period, bioavailability improved, when clinical application, can reduce frequency of injection, reduce the toxic side effect producing in existing treatment plan.

Another object of the present invention is to provide a kind of preparation method of the HCG-Fc of restructuring fusion rotein, and this preparation method comprises:

(1) expression vector of structure coding restructuring HCG-Fc fusion rotein;

(2) stably express of restructuring HCG-Fc fusion rotein in mammalian host cell;

(3) high-density cells is cultivated restructuring HCG-Fc fusion rotein;

(4) purification of restructuring HCG-Fc fusion rotein.

Specifically, the expression vector step that builds coding restructuring HCG-Fc albumen is: adopt artificial synthesis to obtain coding restructuring HCG-Fc antigen-4 fusion protein gene and carried out codon optimized nucleotide sequence (as shown in SEQ ID NO:1,3 and 5), be inserted into mammalian cell expression vector (as pCDNA3), acquisition contains HCG-Fc destination gene expression plasmid pCDNA3-HCG-Fc (Fig. 6), and preferred nucleotide sequence is as SEQ ID NO:1.The nucleotide sequence optimization of gene is that the codon based on mammalian host cell preference is selected design.

Described mammalian cell expression vector can adopt commercially available but be not limited to, as: pCDNA3, pCMV/ZEO, pIRES, pDR, pBK, pSPORT etc. can be used for the carrier that eukaryotic cell system is expressed, preferably, and pCDNA3.

The stably express step of restructuring HCG-Fc fusion rotein in mammalian host cell is: the expression plasmid that contains HCG-Fc albumen is transfected into suitable mammalian host cell, utilizes selection markers screening and amplification selected marker to obtain the cell strain of stablizing high-expression target proteins.

Described mammalian host cell comprises CHO, HEK293, COS, BHK, NS0 and Sp2/0 cell.Preferably, Chinese hamster ovary celI; More preferably, tamed DHFR (Dihydrofolate Reductase, Tetrahydrofolate dehydrogenase) defective type Chinese hamster ovary celI (the abbreviation CHO-DHFR that adapts to suspension growth in serum free medium ^-).

Described transfection method comprises calcium phosphate method, and electricity turns method, liposome transfection, and preferred transfection method is that electricity turns method.

Described screening method is first to utilize selection markers to screen, and then can improve expression amount and obtain by amplification selected marker and stablize overexpression cell line.Selection markers is any one suitable selectivity resistance marker known in the art, as ZEO (Zeocin, bleomycin), G418 (aminoglycoside antibiotics), PUR (puromycin, tetracycline), HYP (Hygromycin, Totomycin), preferred resistant gene is ZEO; Selection markers also can be any one fluorescent mark gene known in the art, comprise GFP (Green Fluorescent Protein, green fluorescent protein), RFP (Red Fluorescent Protein, red fluorescent protein), preferred fluorescent mark gene is GFP.Amplification selected marker is DHFR sequence or GS (Glutaminesynthetase, glutamine synthetase) sequence known in the art, and the selected gene that preferably increases is DHFR.Due to CHO-DHFR-cell self disappearance Tetrahydrofolate dehydrogenase (DHFR), cannot self tetrahydrobiopterin synthesis folic acid, so must just can survive in the nutrient solution that has added xanthoglobulin (hypoxanthine), thymus pyrimidine (Thymidine) and glycine.And by goal gene and DHFR gene co-transfection, not only obtain not containing the cell clone that also can grow on the substratum of above-mentioned additive, what is more important is because DHFR can be by folacin MTX (Methotrexate, methotrexate) institute suppress, under MTX concentration selective pressure, DHFR gene a lot of copy number that must increase could be survived, thereby obtains anti-MTX clone; Again owing to tending to be incorporated into the same area on cell chromosome with the goal gene of DHFR gene co-transfection together with it, so the sequence fragment of encoding exogenous recombinant protein also increases along with the amplification of DHFR gene, can obtain the cell clone of mass expressing external albumen.

The step that high-density cells is cultivated restructuring HCG-Fc fusion rotein is: the above-mentioned stable cell line screening is proceeded to shaking flask or biological reactor carries out large scale culturing, particularly, the present invention, by the optimization to cell culture condition, obtains the cell culture fluid of high expression level restructuring HCG-Fc fusion rotein.The degree of glycosylation that cell culture processes of the present invention can be realized high-density cells cultivation, recombinant proteins and output lifting, recombinant protein increases and sialic acid content raising.

The optimization of described cell culture condition comprises cooling culture method, specifically, and when cell density reaches 1 × 10 ⁷individual/when mL, temperature to be down to 33 ℃ by 37 ℃, at this temperature, cultivate until express output and no longer increase.The method can improve the cumulative withdrawal of activity level and the recombinant protein of expressing protein.

The optimization method of described cell culture condition is also included in substratum and adds special additive, preferably, adds 100 μ M Cu at basic medium ²⁺, feeding substratum adds 2mM ManNAc (N-ethanoyl-D-epichitosamine).The method can make to recombinate degree of glycosylation of HCG-Fc fusion rotein increases, and sialic acid content improves approximately 20%.

The purification step of restructuring HCG-Fc fusion rotein is:

1) Protein A affinity chromatography: centrifugal, collect supernatant, the characteristic of albumen coupling Fc fragment according to the present invention, utilizes affine ProteinA column chromatography.

2) hydrophobic chromatography column purification: adopt hydrophobic chromatography post, according to the hydrophobicity difference of restructuring HCG-Fc fusion rotein, further remove the impurity in target protein after above-mentioned ProteinA purifying.

Described drainage column comprises Butyl Sepharose4Fast Flow, Octyl Sepharose4Fast Flow, Phenyl Sepharose6Fast Flow, Butyl-S Sepharose6Fast Flow, Butyl Sepharose4B, Octyl Sepharose CL-4B, Phenyl Sepharose CL-4B.Preferably, Phenyl Sepharose6Fast Flow.

The preparation method of restructuring HCG-Fc fusion rotein disclosed in this invention, this preparation method can obtain and express the high restructuring of output HCG-Fc fusion rotein.Because of with the coupling of IgG Fc variant, the recombinant protein forming can obtain efficiently purifying easily by ProteinA affinity chromatography.The fusion rotein purity obtaining after hydrophobic chromatography is further purified reaches more than 98%.In addition, in the restructuring HCG-Fc fusion rotein that the present invention announces, α chain and β chain can correctly fold, and have avoided α-α dimer, the dimeric appearance of β-β, have greatly simplified purification step, have reduced production cost.

An also object of the present invention has been to provide a kind of pharmaceutical composition that contains long-acting restructuring HCG-Fc fusion rotein, it is characterized in that, comprise pharmaceutically acceptable carrier or vehicle or thinner, and the recombinant long-acting HCG-Fc fusion rotein of the present invention of significant quantity.

Specifically, described pharmaceutical composition contains significant quantity (as 0.000001-90wt%; Preferably 0.1-50wt%; Better, 5-40wt%) recombinant long-acting HCG-Fc fusion rotein of the present invention, and pharmaceutically acceptable carrier.Conventionally, the fusion rotein of the present invention of significant quantity can be formulated in to nontoxic, inertia with pharmaceutically acceptable aqueous carrier medium in, wherein pH is about 5-8 conventionally, preferably, pH is about 6-8.

Described pharmaceutically acceptable carrier comprises (but being not limited to): sucrose, N.F,USP MANNITOL, polysorbas20 (Tween20), methionine(Met), salt solution, damping fluid, glucose, water, glycerine and composition thereof.Conventionally pharmaceutical preparation should match with administering mode, and pharmaceutical composition of the present invention can be made into injection form, for example, with physiological saline or contain glucose and the aqueous solution of other assistant agents is prepared by ordinary method.Described pharmaceutical composition should be manufactured under aseptic condition.The dosage of activeconstituents is treatment significant quantity.Pharmaceutical preparation of the present invention also can be made into sustained release preparation.

The significant quantity of fusion rotein of the present invention can change with severity of the pattern of administration and disease to be treated etc.The selection of preferred significant quantity can be determined (for example, by clinical trial) according to various factors by those of ordinary skills.Described factor includes but not limited to: the pharmacokinetic parameter biological example utilization ratio of described fusion rotein, metabolism, transformation period etc.; Animal will be treated the severity of disease, the body weight of animal, immune state, the route of administration etc. of animal.

A further object of the present invention is that restructuring HCG-Fc fusion rotein is in the application treating and/or preventing in people's infertility.

Restructuring HCG-Fc fusion rotein Half-life in vivo significant prolongation of the present invention, bioavailability obviously improves, thereby has improved pharmacokinetics and drug effect, with existing HCG comparison, in clinical application, can reduce patient infusion number of times and dosage, reduce side effect, alleviate patient suffering and economical load.

The advantage of restructuring HCG-Fc fusion rotein of the present invention and preparation method thereof is summarized as follows:

1. restructuring HCG-Fc fusion rotein of the present invention is the dimer protein being formed by IgG Fc variant (vIgG2Fc, vIgG4Fc or vIgGIFc) and HCG coupling, Half-life in vivo that can significant prolongation albumen, greatly improve the expression amount of HCG in Chinese hamster ovary celI, there is significant inside and outside activity.

2. the α chain of dimerization strand HCG-Fc fusion rotein and β chain are correctly folding with covalent linkage, avoid forming α-α dimer and β-β dimer, have greatly simplified purifying process, reduce production costs.

3. restructuring HCG-Fc fusion rotein Half-life in vivo significant prolongation of the present invention, its transformation period is 10 times that existing people urinates HCG and restructuring HCG, and absolute bioavailability is 2 times that people urinates HCG and restructuring HCG, can greatly reduce frequency injection and reduce injected dose, alleviating the side effect that existing treatment plan produces.

Accompanying drawing explanation

Fig. 1. show the comparison of the hinge region of human IgG1, IgG2, IgG4 and their variants and the aminoacid sequence in CH2 region.Relatively this three partial amino-acid series: amino acid region 228,234-237 and 330-331.The amino acid mutation of these variants shows with bold Italic.Amino-acid residue numbering is to demarcate according to EU number system.

Fig. 2. show HCG-Fc strand and dimerization structural representation.A) strand HCG-Fc; B) HCG-Fc of dimerization.

Fig. 3. show the nucleotide sequence of the HCG-Fc of HindIII-EcoRI fragment and the aminoacid sequence of derivation in PCDNA3 expression vector.The nucleotide sequence of HCG-Fc comprises that coding is containing leading peptide (1-20), ripe HCG β chain, ripe HCG α chain, peptide linker, IgG2Fc variant (vIgG2Fc).Ripe restructuring HCG-Fc fusion rotein contains ripe HCG β chain (21-165), ripe α chain (166-257), peptide linker (258-273) and IgG2Fc variant (vIgG2Fc) (274-496).

Fig. 4. show the nucleotide sequence of the HCG-Fc of HindIII-EcoRI fragment and the aminoacid sequence of derivation in PCDNA3 expression vector.The nucleotide sequence of HCG-Fc comprises that coding is containing leading peptide (1-20), ripe HCG β chain, ripe HCG α chain, peptide linker, IgG4Fc variant (vIgG4Fc).Ripe restructuring HCG-Fc fusion rotein contains ripe HCG β chain (21-165), ripe HCG α chain (166-257), peptide linker (258-273) and IgG4Fc variant (vIgG4Fc) (274-502).

Fig. 5. show the nucleotide sequence of the HCG-Fc of HindIII-EcoRI fragment and the aminoacid sequence of derivation in PCDNA3 expression vector.The nucleotide sequence of HCG-Fc comprises that coding is containing leading peptide (1-20), ripe HCG β chain, ripe HCG α chain, peptide linker, IgG1Fc variant (vIgG1Fc).Ripe restructuring HCG-Fc fusion rotein contains ripe HCG β chain (21-165), ripe HCG α chain (166-257), peptide linker (258-273) and IgG1Fc variant (vIgG1Fc) (274-500).

Fig. 6. show the eukaryon expression plasmid collection of illustrative plates of constructed coding HCG-Fc fusion rotein.This expression plasmid total length 9063bp, contains 10 oligogene segments, comprises 1.CMV promotor; 2. target gene HCG-Fc; 3.IRES; 4.Zeocin resistance screening gene; 5.BGH terminator; 6.SV40 promotor; 7.DHFR amplification gene; 8.SV40 terminator; 9. ampicillin resistance gene (Ampicillin); 10.ColE1 replication orgin (Ori).

Fig. 7. shown the accumulation tendency graphic representation of the HCG-Fc cell strain expression-secretion HCG-Fc albumen of recombinating in 7L bio-reactor.

Fig. 8 .Westem bloting result has shown the successful expression of restructuring HCG-Fc fusion rotein in Chinese hamster ovary celI.Non-reduced glue, Lane1: the HCG (50KDa) in urine source; Lane2: restructuring HCG-vIgG2Fc fusion rotein of the present invention (148KDa); Lane3: restructuring HCG-vIgG1Fc fusion rotein of the present invention (148KDa); Lane4: restructuring HCG-vIgG4Fc fusion rotein of the present invention (148KDa).

Fig. 9. show recombinant single chain and the 10%SDS-PAGE electrophoretogram of dimerization HCG-Fc fusion rotein under reductive condition and non-reduced condition of purifying.Lane1: non-reduced glue, restructuring dimerization HCG-vIgG2Fc fusion rotein (148KDa) Lane2: non-reduced glue, restructuring dimerization HCG-vIgG1Fc fusion rotein (148KDa); Lane3: non-reduced glue, restructuring dimerization HCG-vIgG4Fc fusion rotein (148KDa); Lane4: go back virgin rubber, recombinant single chain HCG-vIgG2Fc fusion rotein (74kDa); Lane5: go back virgin rubber, recombinant single chain HCG-vIgG1Fc fusion rotein (74kDa); Lane6: go back virgin rubber, recombinant single chain HCG-vIgG4Fc fusion rotein (74kDa).

Figure 10. the restructuring HCG-Fc fusion rotein, the people that have shown purifying urinate HCG and the metabolic chart of restructuring HCG in rat body.A) restructuring HCG-vIgG2Fc, restructuring HCG-vIgG4Fc and restructuring HCG-vIgG1Fc; B) people urinates HCG and restructuring HCG.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment are only not used in and limit the scope of the invention for the present invention is described.The experimental technique of unreceipted actual conditions in the following example, according to normal condition as people such as Sambrook, molecular cloning: laboratory manual (New York:Cold Spring Harbor Laboratory Press, 1989) condition described in, or the condition of advising according to manufacturer.

Embodiment 1. builds the expression vector of coding restructuring HCG-Fc fusion rotein

Gene order design is to be optimized based on Chinese hamster ovary celI preference codon, adopt synthetic the encode signal peptide of HCG albumen β chain and the fusion gene of mature peptide section and HCG α chain mature peptide section thereof of containing through optimizing of method of synthetic, the 756bp DNA fragmentation of synthesized is inserted to transfer vector as between the EcoRV restriction enzyme site in pUC57, obtain HCG plasmid (pHCG), used the exactness of DNA sequencing method validation insertion sequence.

Synthetic contains BamHI (5 ' end) and the flexible peptide linker of coding (Linker detects " L ") of EcoRI (3 ' end) restriction enzyme site and fusion gene L-vIgG2Fc, L-vIgG4Fc and the L-vIgG1Fc of Fc variant (vIgG2Fc, vIgG4Fc and vIgG1Fc) fragment respectively.The fusion gene fragment of acquisition is inserted into respectively to transfer vector as between the BamHI of PUC19 and EcoRI site, obtains the plasmid containing three kinds of variants, be respectively pL-vIgG2Fc, pL-vIgG4Fc and pL-vIgG1Fc.Verify the gene order of L-vIgG2Fc, L-vIgG4Fc and L-vIgG1Fc by DNA sequencing.For preparing two kinds of HCG-L-Fc fusion genes, with restriction enzyme SpeI and BamHI double digestion pHCG plasmid, after gel electrophoresis, glue reclaims the signal peptide of coding HCG albumen β chain and the fusion gene fragment of mature peptide section and HCG α chain mature peptide section thereof, purified said gene fragment is inserted into respectively 5 '-end of peptide linker in pL-vIgG2Fc, pL-vIgG4Fc and pL-vigG1Fc plasmid, and T4 ligase enzyme connects and composes pHCG-L-vIgG2Fc, pHCG-L-vIgG4Fc and pHCG-L-vIgG1Fc plasmid.Constructed fusion gene is made up of HCG β, HCG α, peptide linker and Fc variant gene, and its nucleotide sequence is as shown in SEQ ID NO:1,3 and 5, and as shown in Figure 2 a, dimerization structure as shown in Figure 2 b for its single-stranded structure.

Restriction enzyme SpeI/EcoRI is double digestion pHCG-L-vIgG2Fc, pHCG-L-vIgG4Fc and pHCG-L-vIgG1Fc plasmid respectively, and DNA gel purifying obtains HCG-L-vIgG2Fc, HCG-L-vIgG4Fc and HCG-L-vIgG1Fc fragment.Two kinds of good purifying HCG-L-Fc fragments are inserted into mammalian cell expression plasmid as between the corresponding restriction enzyme site of pCDNA3 (Invitrogen), final acquisition containing fusion gene expression plasmid pCDNA3-HCG-vIgG2Fc, pCDNA3-HCG-vIgG1Fc and pCDNA3-HCG-vIgG4Fc, be referred to as pCDNA3-HCG-Fc plasmid, as shown in Figure 6.This plasmid is containing the required promotor CMV of mammal cell with high efficient expression alien gene albumen; This plasmid also contains two kinds of selected markers, thereby can have amicillin resistance in bacterium, can have bleomycin (zeocin) resistance in mammalian cell.In addition, in the time that host cell is DHFR genetic expression defective type, Tetrahydrofolate dehydrogenase (DHFR) gene of the contained mouse of PCDNA3 expression vector, makes it in the time that methotrexate (MTX) exists, can coamplification pHCG-Fc fusion gene and DHFR gene.

The coupling of carrying out HCG and Fc fragment by peptide linker (preferably for flexible joint) can improve the biological activity of albumen; for the purpose of the present invention; preferably length is approximately 20 or (but can not be less than 2) amino acid whose peptide linker still less; certainly by the peptide linker of 1 Amino acid profile also in protection scope of the present invention, should use and contain or by 2 or the peptide linker of oneself following Amino acid profile of multiselect more: glycine, Serine, L-Ala and Threonine.The peptide linker of the embodiment of the present invention contains Gly-Ser peptide member, and its aminoacid sequence is GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer.

Embodiment 2. stably express of HCG-Fc fusion rotein in mammalian cell of recombinating

The expression plasmid pCDNA3-HCG-L-Fc that embodiment 1 is built is transfected into DHFR deficient CHO host cell (CHO-DHFR ^-), Fig. 2 b has shown the schematic diagram of restructuring dimerization HCG-Fc fusion rotein.Adopt electroporation method to carry out transfection, use the Gene Pulser Electroporator (Bio-Rad Laboratories, Hercules, CA) of 960 μ Fd electric capacity, its electric field is set to 250V, in cuvette 2～5 × 10 ⁷in individual cell, add the linearizing plasmid DNA of 10 μ g PvuI.In transfection two days later, make substratum into growth medium containing 100 μ g/mL Zeocin resistant maker genes, obtain the transfectant through resistance primary dcreening operation.Adopt the method for westem blotting, with the expression of anti-HCG antibody test HCG-Fc, as Fig. 8.Utilize DHFR amplification selected marker to improve the expression level of restructuring dimerization albumen, in the growth medium that contains progressive concentration MTX, use the restructuring dimerization protein gene of DHFR gene coamplification transfection for this reason.The transfectant that can grow in up to 10 μ M/mLMTX substratum with Method of Limited Dilution method subclone.The secretion rate of subclonal cell line is done further to analyze.Screening secretion level exceedes approximately 10 (preferably approximately 20) μ g/10 ⁶the cell strain of (1,000,000) individual cell/24 hour, obtains and stablize the recombinate cell strain of HCG-Fc fusion rotein of high expression level.

Embodiment 3. recombinate production and the purifying of HCG-Fc fusion rotein

The high yield cell strain that adopts embodiment 2 to obtain, first in culture dish, carrying out serum-free domestication cultivates, then transfer in shaking flask and suspend and tame cultivation, in domestication process, carry out the screening of substratum simultaneously, add growth conditions, the growth tendency of different composition observation of cell, and the biochemical indicator such as activity and sialic acid of expression product, preferred cell culture condition is: basic medium adds 100 μ M Cu ²⁺, feeding substratum adds 2mM ManNAc (N-ethanoyl-D-epichitosamine), and the method can make to recombinate degree of glycosylation of HCG-Fc fusion rotein increases, and sialic acid content improves approximately 20%.After taming successfully, carry out cell amplification, amplification, to q.s, is carried out the monitoring of 7L bio-reactor and is cultivated, and exceedes 1 × 10 at cell density ⁷individual/to start to be cooled to 33 ℃ of cultivations when mL, batch growth cycle is 20 days.Recombinant protein is carried out to preliminary purification with 1ml ProteinA column chromatography, measure the expression amount of restructuring HCG-Fc fusion rotein, result demonstration, the cumulative withdrawal that restructuring HCG-vIgG2Fc, restructuring HCG-vIgG4Fc and restructuring HCG-L-vIgG1Fc cell strain are expressed is respectively 1.20g/L, 0.89g/L, 0.82g/L (Fig. 7).

The purifying of restructuring HCG fusion rotein comprises the following steps:

1) ProteinA affinity chromatography: centrifugal, collect supernatant, according to the present invention, the characteristic of albumen coupling Fc fragment, utilizes affinity chromatography method, supernatant liquor is loaded onto to the Protein A post of phosphate buffer saline (PBS) balance; Fusion rotein to be reorganized is incorporated into after ProteinA, wash this post with PBS, until OD280 value is lower than 0.01, then the restructuring HCG-Fc fusion rotein of the sodium-acetate buffer elution of bound that is 4.0 with 20mM pH, finally with in the 1M Tris-HCl damping fluid of pH10.0 and the active liquid of collecting.The HCG-Fc purity of protein of purifying can reach more than 95%.

2) hydrophobic chromatography: with hyperfiltration process, above-mentioned protein A activity being collected to fluid exchange is 20mMTris-HCl-1.5M NaCl (pH8.0) damping fluid, by this sample pipetting volume to the phenyl-6Fast Flow post of crossing by 20mM Tris-HCl-1.5M NaCl (pH8.0) balance, first use identical balance liquid drip washing, use again 20mM Tris-HCl-1.35M NaCl (pH8.0) drip washing, finally use 20mM Tris-HCl-0.5M NaCl (pH8.O) buffer solution elution.

Western bloting result has shown the successful expression of restructuring HCG-Fc fusion rotein in Chinese hamster ovary celI, as shown in Figure 8, SDS-PAGE gel electrophoresis collection of illustrative plates under non-reduced condition, people urinates HCG (commerical prod) and restructuring of the present invention HCG-Fc fusion rotein shows corresponding target protein hybridization band at 50KDa and 148KDa respectively, has verified in the restructuring HCG fusion rotein that the present invention obtains and has contained HCG albumen.Fig. 9 be purifying HCG-Fc fusion rotein reduction and non-reduced condition under SDS-PAGE gel electrophoresis collection of illustrative plates.Result show, the HCG-Fc purity of protein of purifying can reach more than 98%, the molecular weight of HCG-Fc under reductive condition be under non-reduced condition molecular weight 50%.Confirm its aminoacid sequence and SEQ ID NO:2,4 and 6 identical through 15 determined amino acid sequences of N end.

The recombinate inside and outside determination of activity of HCG-Fc fusion rotein of embodiment 4.

The external activity (immunogen activity) of restructuring HCG-Fc fusion rotein restructuring HCG-vIgG2Fc of the present invention, restructuring HCG-vIgG4Fc and restructuring HCG-vIgG1Fc adopts the HCG enzyme immunoassay detection kit that BIOCHECK (U.S.) company produces to detect, method reference reagent box specification sheets.Activity in vivo adopts the ovary weightening finish method in 2010 editions " British Pharmacopoeias " to detect.Protein content determination uses LOWRY quantitative method.Urinate HCG, restructuring HCG and restructuring HCG-Fc fusion rotein (restructuring HCG-vIgG2Fc, restructuring HCG-vIgG4Fc and restructuring HCG-vIgG1Fc) is estimated to tire according to standard substance labelled amount, people, with diluent (containing 0.1%BSA, the phosphate buffered saline buffer of pH7.2 ± 0.2), standard substance, people are urinated to HCG, restructuring HCG and restructuring HCG-Fc fusion rotein is mixed with the working fluid containing HCG0.5IU/ml, 1IU/ml, high, normal, basic three dosage of 2IU/ml.Select 19～28 ages in days, the age must not differ and exceedes 3, and body weight must not differ and exceeded the male mouse of SD of 10 grams.Standard substance, people urinate HCG group, restructuring HCG and HCG-Fc group and are divided into high, normal, basic three dosage, every group of 6 animals.Subcutaneous injection after rat neck, injects twice every day, and per injection volume is 0.5ml, injects continuously four days, and every day is in same time administration.Last drug administration by injection, after 24 hours, adopts dislocation method to put to death animal according to order of administration, gets seminal vesicle, peels off after blotting surface-moisture and weighs, and records organ weight.According to standard substance seminal vesicle, weightening finish adopts the activity that parallel line analysis method calculating people urinates HCG, restructuring HCG and HCG-Fc.Record the external activity that restructuring HCG-vIgG2Fc, restructuring HCG-vIgG4Fc, restructuring HCG-vIgG1Fc, restructuring HCG and people urinate HCG and be respectively 9961IU/ml, 9305IU/ml, 9521IU/ml, 8966IU/ml and 8369IU/ml, its activity in vivo is respectively 9120IU/ml, 8990IU/ml, 8780IU/ml, 8253IU/ml and 8011IU/ml.Result shows, restructuring HCG-Fc fusion rotein of the present invention has inside and outside biologic activity.

The recombinate pharmacokinetics test of HCG-Fc fusion rotein of embodiment 5.

Be divided into restructuring HCG-vIgG2Fc, restructuring HCG-vIgG4Fc, restructuring HCG-vIgG1Fc, restructuring HCG administration group and people urinates HCG administration group, 3 of every group of male SD rats of selecting body weight 200-250g, give subcutaneous injection after neck by 10000IU/kg respectively.Restructuring HCG combination people urinates HCG group 1h, 2h, 4h, 6h, 8h, 10h, 12h, 24h, 36h, 48h, 56h, 72h after administration and carries out eye socket venous blood collection, restructuring HCG-Fc fusion rotein respectively after administration 1h, 2h, 4h, 6h, 8h, 10h, 12h, 24h, 36h, 48h, 56h, 72h, 96h, 144h, 264h, 312h, 384h, 432h, 528h carry out eye socket venous blood collection.In addition, separately get respectively 3 rats for every group and carry out the dosage intravenous administrations such as relative medicine, same blood sampling time point is taken a blood sample.Blood sample, after the centrifugal 5min of 3000rpm, is drawn serum ,-20 ℃ of preservations., adopt ELISA test kit (BIOCHECK, the U.S.) to measure HCG immunocompetence in each time point blood plasma.Use kinetica4.4 software, calculate each group of main pharmacokinetic parameter by statistics moments method.As shown in figure 10, the transformation period, result was as table 1 for each group pharmacokinetic curve.Result shows, people urinates the elimination transformation period of HCG in rat body and is about 15.3h, and the present invention is respectively 168.33h, 166.82h and 156.63h at recombinate elimination transformation period of HCG-vIgG2Fc, restructuring HCG-vIgG4Fc, restructuring HCG-vIgG1Fc fusion rotein, be that people urinates HCG and restructuring the more than 10 times of HCG.The AUC that subcutaneous injection medicine is calculated calculates the AUC of gained divided by intravenous injection, be absolute bioavailability, the absolute bioavailability of HCG-vIgG2Fc, restructuring HCG-vIgG4Fc, restructuring HCG-vIgG1Fc fusion rotein of wherein recombinating is that restructuring HCG and people urinate the more than 2 times of HCG, results suggest, HCG urinates HCG with people and compares with restructuring, reaches that the required frequency injection of same curative effect restructuring HCG-Fc fusion rotein greatly reduces, dosage significantly reduces.

Table 1 recombinate transformation period and the bioavailability of HCG-Fc fusion rotein

Embodiment 6. ovulation effect of HCG-Fc fusion rotein to female rats of recombinating

105 of Healthy female SD rats, body weight 200-250g normally feeds and supports quarantine observation more than 7 days under experimental situation.Be divided at random 7 groups: negative control group (physiological saline 0.2ml/ only), restructuring HCG-vIgG2Fc administration group (6IU/ only), restructuring HCG-vIgG1Fc administration group (6IU/ only), restructuring HCG-vIgG4Fc administration group (6IU/ only), restructuring HCG control group (10IU/ only), people urinate HCG control group (10IU/ only), every group of 15 rats, respectively organize rat body weight and distribute similar.First observe animal oestrus cycle one-period by vaginal smear method.Afterwards, start subcutaneous injection rhFSH (fruit receive sweet smell) in dioestrus first day 10:00 in the morning, dosage is 15IU/kg/d, successive administration 3 days, same time administration every day.(proestrum) on the 4th, respectively by grouping subcutaneous injection medicine, 10IU/ only.After (rutting sedson) morning on the 5th, 10:00 anaesthetized rat, carry out ovary separation, and weigh, liquid-solid fixed with BouinShi to the ovary separating, paraffin embedding, does serial section to fixing ovary every 6 μ m, under microscope, carry out histological observation, and record follicle number.

The count results of each group Rat Ovulation number of animals, ovulation rate (ovulation number of animals/animal number) and large follicle number is in table 2, result shows, the present invention recombinate HCG fusion rotein, restructuring HCG and people urinates HCG all female rats is had to ovulation effect, ovulation number of animals and ovulation rate and negative control group more all have significant difference (P < 0.01), and large follicle number and negative control group more all have significant difference (P < 0.01).And three kinds of the present invention restructuring HCG-Fc fusion roteins only need be injected compared with low dosage (6IU/ only) and just can reach to restructuring HCG (10IU/ only) and people and urinate the similar curative effect of HCG (10IU/).

Table 2 ovulation effect of HCG-Fc fusion rotein to female rats of recombinating

Note: X ²check, with negative control group comparison, ^*p < 0.05, ^*p < 0.01.

The embodiment 8. HCG-Fc fusion rotein of recombinating causes the safety testing of rat ovary hyperstimulation syndrome

60 22 age in days female Wistar rats are divided at random and are divided into Normal group, restructuring HCG-vIgG2Fc administration group, restructuring HCG-vIgG1Fc administration group, restructuring HCG-vIgG4Fc administration group, people and urinate HCG control group and restructuring HCG control group, 10 every group.The rat of restructuring HCG-vIgG2Fc administration group, restructuring HCG-vIgG1Fc administration group and restructuring HCG-vIgG4Fc administration group 22-25 age in days all in the morning 9:00 according to 10IU/ only/d dosage abdominal injection rhFSH (fruit receive sweet smell), the 26th age in days 9:00 in the morning press 18IU/ (3 times of drug effect dosage) corresponding restructuring of subcutaneous injection HCG-Fc; People urinate HCG and restructuring HCG administration group 22-25 age in days all in the morning 9:00 according to 10IU/ only/d dosage abdominal injection rhFSH (fruit receive sweet smell), the 26th age in days 9:00 in the morning press 30IU/ (3 times of drug effect dosage) corresponding HCG of the corresponding injection of subcutaneous injection; Normal group injection equal-volume physiological saline.All groups all at the 28th age in days 9:00 in the morning through tail vein injection 1%EB dyestuff 0.1ml, after 30min, de-neck method is put to death rat, carries out immediately ascites scoring.Without ascites or a small amount of ascites person to intraperitoneal perfusion 5ml physiological saline, perfusion liquid is collected in 10ml test tube, all be diluted to 10ml, add again 0.05ml0.1MNaOH solution, with the at room temperature centrifugal 10min of speed of 3000r/min, in the row colorimetric estimation of wavelength 600nm place, record OD value with spectrophotometer.Finally, winning both sides ovary weighs.Observation index is: 1, abdominal cavity capillary permeability: according to normal concentration and OD value drawing standard curve thereof, calculate peritoneal fluid EB content.2, ascites scoring: 1 point: without ascites; 2 points: a small amount of ascites exists; 3 points: middle amount ascites exists; 4 points: ascites obviously exists; 5 points: a large amount of ascites exists or ascites is overflowed from abdominal incision.3, ovary weight.

Experimental result is in table 3, result shows, although under 3 times of drug effect dosage, restructuring HCG-Fc fusion rotein has effect of gain to the ovary of children's female Wistar rats in age, but in ascites scoring and two indexs of abdominal cavity capillary permeability, there is no significant difference with Normal group, do not cause ovarian hyperstimulation syndrome.And the people of same dosage urinates HCG control group and recombinates HCG control group compared with Normal group, all obviously higher aspect ascites scoring, abdominal cavity capillary permeability and ovary weight, and there is significant difference (P < 0.05), illustrate and caused ovarian hyperstimulation syndrome.Meanwhile, people urinates HCG control group and restructuring HCG control group indices apparently higher than three restructuring HCG-Fc administration groups (P < 0.05).Result shows, under equal higher dosage, the present invention recombinates, and to urinate HCG side effect less for HCG-vIgG2Fc, restructuring HCG-vIgG1Fc and the restructuring relative HCG of restructuring of HCG-vIgG4Fc and people, and clinical application is safer.

EB content and ovary weight comparison in the scoring of the each group of table 3 ascites, peritoneal fluid

Note: t check, with Normal group this, ^ap < 0.05; Compared with restructuring HCG group, ^bp < 0.05; With people urinate HCG group mutually this, ^cp < 0.05.

Claims

1. restructuring HCG-Fc fusion rotein, is characterized in that, described fusion rotein is dimerization fusion rotein, and its aminoacid sequence holds C end to comprise successively HCG β subunit, HCG α subunit, peptide linker and human IgG Fc variant from N.

2. restructuring HCG-Fc fusion rotein according to claim 1, the aminoacid sequence of wherein said HCG β subunit is the aminoacid sequence shown in the HCG β SEQ ID NO:8 after the 1-18 amino acids residue of having removed in conventional H CG β subunit; The amino acid residue sequence of wherein said HCG α subunit is the aminoacid sequence shown in the HCG α SEQ ID NO:7 after the 1-24 amino acids residue of having removed in conventional H CG α subunit; Wherein said peptide linker contains 2-20 amino acid, described peptide linker is present between HCG α subunit and human IgG Fc variant, and peptide linker contains two or more and is selected from the amino acid of glycine, Serine, L-Ala and Threonine, and preferred sequence is GlySerGlyGlyGlySerGlyGlyGlyGlySerGlyGlyGlyGlySer.

3. according to the restructuring HCG-Fc fusion rotein of claim 1, wherein said human IgG Fc variant is selected from lower group:

(i) human IgG2's hinge region, CH2 and the CH3 region of containing Pro331Ser sudden change;

(ii) human IgG 4 hinge regions, CH2 and the CH3 region of containing Ser228Pro and Leu235Ala sudden change;

(iii) human IgG l hinge region, CH2 and the CH3 region of containing Leu234Val, Leu235Ala and Pro331Ser sudden change.

4. restructuring HCG-Fc fusion rotein according to claim 1, is characterized in that, the aminoacid sequence of described fusion rotein is as shown in SEQ ID NO:2,4 and 6.

5. coding, according to the nucleotide sequence of the restructuring HCG-Fc fusion rotein of claim 1, is characterised in that its sequence is as shown in SEQ ID NO:1,3 and 5.

6. a preparation method for the restructuring HCG-Fc fusion rotein of claim 1, its step comprises:

1) expression vector of structure coding restructuring HCG-Fc fusion rotein:

Adopt artificial synthesis to obtain the gene of coding HCG-Fc fusion rotein, be inserted into mammalian cell expression vector, obtain the expression plasmid that contains HCG-Fc antigen-4 fusion protein gene;

2) stably express of restructuring HCG-Fc fusion rotein in mammalian host cell:

The expression vector that contains HCG-Fc fusion rotein is transfected into mammalian host cell, the cell strain of screening stably express HCG-Fc fusion rotein;

3) high-density cells is cultivated restructuring HCG-Fc fusion rotein:

The above-mentioned stable cell line screening is proceeded to shaking flask or cell response tank carries out large scale culturing, when cell density reaches 1 × 10 ⁷individual/when mL, temperature to be down to 33 ℃ by 37 ℃, at this temperature, cultivate until express output and no longer increase;

4) purification of restructuring HCG-Fc fusion rotein:

A) Protein A affinity chromatography: centrifugal, collect supernatant, the characteristic of albumen coupling Fc fragment according to the present invention, utilizes affine ProteinA column chromatography;

B) hydrophobic chromatography column purification: further remove the impurity in target protein after above-mentioned Protein A purifying through hydrophobic chromatography purifying;

7. the preparation method of restructuring according to claim 6 HCG-Fc fusion rotein, wherein step 1) described in expression vector be pCDNA3, pCMV/ZEO, pIRES, pDR, pBK, pSPORT or pCMV-DHFR, preferably, pCDNA3; Wherein step 2) described in cell transfecting method comprise electroporation transfection method, calcium phosphate transfection, liposome transfection and Protoplast fusion, preferably, electroporation transfection method; Described mammalian host cell comprises CHO, HEK293, BHK, NS0 and Sp2/0 cell, preferably, Chinese hamster ovary celI, more preferably, DHFR deficient CHO-suspension cell (DHFR-CHO).

8. the preparation method of restructuring according to claim 6 HCG-Fc fusion rotein, wherein step 3) in be also included in substratum and add additive, preferably, add 100 μ M Cu at basic medium ²⁺, feeding substratum adds 2mM ManNAc (N-ethanoyl-D-epichitosamine).

9. a pharmaceutical composition, is characterized in that, comprises pharmaceutically acceptable carrier or vehicle or thinner, and restructuring HCG-Fc fusion rotein described in the claim 1-8 any one claim of significant quantity.

10. the application of the restructuring HCG-Fc fusion rotein of claim 1 in the infertile disease drug of preparation treatment.