An antibody against human igg protein and application thereof

Abstract

The application discloses an antibody against human IgG protein and application thereof. The antibody of some examples of the application has high adsorption performance to human IgG and good specificity. The antibody of some examples of the application has better adsorption performance to human IgG than protein A. The antibody of some examples of the application can be prepared into an IgG immunoadsorbent, and excess IgG can be well adsorbed and removed, thereby providing a new direction for treating diseases caused by abnormal IgG.

Description

Technical Field

[0001] This invention belongs to the field of blood immunoadsorption, specifically, it relates to an antibody against human IgG protein and its application. Background Technology

[0002] Immunoglobulins (Ig) are produced by the body in response to antigens (such as pathogens). Their main function is to react with antigens, forming antigen-antibody complexes, thereby blocking the harmful effects of pathogens on the body and rendering them ineffective. Immunoglobulins are classified into five classes: immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin D (IgD), and immunoglobulin E (IgE). IgG is the most abundant in human serum, accounting for 75% of total immunoglobulins. It is the most persistent and important antibody in the primary immune response and plays a crucial role in antibacterial and antiviral processes. Abnormal IgG levels may lead to various immune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, which may be caused by elevated IgG levels. Currently, treatment for the disease mainly relies on immunotherapy with monoclonal antibody drugs. However, the use of immunotherapy is limited by several factors. For example, in order to achieve the effect of immunotherapy, high doses of biological drugs need to be repeatedly administered, which may induce a series of autoimmune-mediated side effects, including immunogenicity, induction of anti-drug antibodies, serum sickness, etc.

[0003] IgG is classified into four subtypes: IgG1, IgG2, IgG3, and IgG4. While structurally similar, their Fc (fragment crystallizable) constant regions exhibit high sequence homology, consisting of a pair of heavy chain CH2 and CH3 constant domains. These are connected by hinge structures to two antigen-binding Fab (fragment of antigen binding) variable regions, including VH and CH1 (heavy chain) and VL and Cκ / λ (light chain) domains. Significant differences exist among the four IgG subtypes in their hinge structures and CH2 domains, primarily in the hinge length. The IgG3 hinge structure is twice the length of the Fc fragment, causing the Fab fragment to be structurally distant from the Fc fragment. Conversely, the IgG2 / IgG4 hinge structure is shorter, placing the Fab fragment structurally closer to the Fc fragment. Currently available monoclonal antibody drugs are mostly domain proteins, with subtypes including IgG1, IgG2, and IgG4, each with different mechanisms for treating diseases. Their Fc fragments can all bind to protein A. However, these proteins are prone to degradation during storage and use, resulting in large batch-to-batch variations and immunogenicity.

[0004] Unlike traditional antibodies, nanobodies are single-domain antibodies with only a heavy chain and no light chain. They have only one variable domain that binds to the antigen, and their size is approximately 12–17 kDa, only one-tenth the size of traditional antibodies (150 kDa). Furthermore, single-domain antibodies have only one domain with a disulfide bond, folding into a relatively stable structure. Studies have shown that single-domain antibodies retain their antigen-binding ability even after incubation at 37°C for one week, allowing them to be used under more stringent chemical and physical conditions during treatment or modification. In addition, the small size of single-domain antibodies helps reduce the number of potentially immunogenic epitopes, while also exhibiting rapid blood clearance and resistance to aggregate formation, resulting in only low immunogenicity. Single-domain antibodies have already shown great potential as tools in various biotechnology fields, including diagnostics and therapy.

[0005] Developing an antibody that can specifically adsorb IgG, maintain sufficiently high antigen specificity and affinity, and be expressed in high yield is of great practical significance for the development of corresponding immunotherapeutic agents. Summary of the Invention

[0006] The purpose of this invention is to overcome at least one deficiency of the prior art and to provide an antibody against human IgG protein and its application.

[0007] The technical solution adopted in this invention is: The first aspect of the present invention provides: An antibody against human IgG protein is composed of a framework region FR1-FR4 and an antigen-binding region CDR1-CDR3, with the amino acid sequences of CDR1-CDR3 being: CDR1: RYAMG, CDR2: SIRWNNGNTYLVDSVKG, and CDR3: RSFGTGQWDY.

[0008] In some examples of antibodies, the amino acid sequences of FR1 to FR4 are as follows: FR1: QVQLQESGGGLVQAGGSLRLSCAVSGNTLS, FR2: WFRQAPGKEREFVG, FR3: RFTISGDNAHDTVHLQMTSLKPEDTGVYFCVA, FR4: WGQGTQVTVSS.

[0009] In some instances, the antibody is a single-domain antibody.

[0010] In some examples of antibodies, the preparation methods include: S1) The nucleotide sequence corresponding to the antibody is linked to the pET-28a vector, with NdeI and XhoI as restriction sites; S2) The ligation product of S1) was transformed into BL21(DE3) competent bacteria for transformation; S3) Recombinant protein expression: Single colonies with correct band sequences as identified by PCR and sequencing were inoculated into LB liquid medium containing kanamycin and cultured until OD. 600 =0.6~0.8, use IPTG to induce, collect the bacterial cells by centrifugation, lyse at low temperature and collect the protein supernatant by centrifugation; S4) Recombinant protein purification: The protein supernatant is purified by affinity chromatography and the elution peak is collected to obtain the antibody protein.

[0011] A second aspect of the present invention provides: An immunoadsorbent comprising a solid support having an antibody as described in the first aspect of the invention coupled to the surface of the solid support.

[0012] In some examples of immunoadsorbents, the solid support is selected from at least one of agarose, chitosan, dextran gel, resin, and cellulose microspheres.

[0013] A third aspect of the present invention provides: The application of the antibody described in the first aspect of this invention in the preparation of IgG immunosorbents.

[0014] In some application examples, the IgG is selected from at least one of the IgG1, IgG2, IgG3 and IgG4 subtypes.

[0015] In some applications, the IgG immunoadsorbent is a blood IgG immunoadsorbent.

[0016] A fourth aspect of the present invention provides: The use of the antibody described in the first aspect of this invention in the preparation of medicaments for treating and / or preventing diseases caused by IgG abnormalities.

[0017] In some application examples, the IgG is selected from at least one of the IgG1, IgG2, IgG3 and IgG4 subtypes.

[0018] In some applications, the disease caused by the IgG abnormality is an autoimmune-related disease.

[0019] In some application examples, autoimmune-related diseases include, but are not limited to, rheumatoid arthritis, systemic lupus erythematosus, and IgG type multiple myeloma.

[0020] A fifth aspect of the present invention provides: The use of the antibody described in the first aspect of this invention in the preparation of immunoglobulin IgG purification agents.

[0021] In some application examples, the IgG is selected from at least one of the IgG1, IgG2, IgG3 and IgG4 subtypes.

[0022] The beneficial effects of this invention are: The antibodies in some examples of this invention have high adsorption performance for human IgG and good specificity.

[0023] The antibodies in some examples of this invention exhibit better adsorption performance for human IgG than protein A.

[0024] The antibodies in some examples of this invention can be prepared as IgG immunoadsorbents, which can effectively adsorb and remove excess IgG, providing a new direction for the treatment of diseases caused by IgG abnormalities. Attached Figure Description

[0025] Figure 1 The results show the binding activity of the single-domain antibody shown in SEQ ID NO: 1 against different IgG subtypes.

[0026] Figure 2 The results show the binding activity of the single-domain antibody shown in SEQ ID NO: 2 against different IgG subtypes.

[0027] Figure 3 The results show the binding activity of the single-domain antibody shown in SEQ ID NO: 3 against different IgG subtypes.

[0028] Figure 4 The results show the binding activity of the single-domain antibody shown in SEQ ID NO: 4 against different IgG subtypes.

[0029] Figure 5 The results show the binding activity of the single-domain antibody shown in SEQ ID NO: 5 against different IgG subtypes.

[0030] Figure 6 The results show the binding activity of different single-domain antibodies to protein A on IgG. Detailed Implementation

[0031] An antibody against human IgG protein is composed of a framework region FR1-FR4 and an antigen-binding region CDR1-CDR3, with the amino acid sequences of CDR1-CDR3 being: CDR1: RYAMG, CDR2: SIRWNNGNTYLVDSVKG, and CDR3: RSFGTGQWDY.

[0032] In some examples of antibodies, the amino acid sequences of FR1 to FR4 are as follows: FR1: QVQLQESGGGLVQAGGSLRLSCAVSGNTLS, FR2: WFRQAPGKEREFVG, FR3: RFTISGDNAHDTVHLQMTSLKPEDTGVYFCVA, FR4: WGQGTQVTVSS.

[0033] In some examples of antibodies, they are single-domain antibodies. Single-domain antibodies have shorter peptide chains, are easier to prepare, and have good stability.

[0034] Antibodies can be prepared using conventional methods. In some examples of antibodies, the preparation methods include: S1) The nucleotide sequence corresponding to the antibody is linked to the pET-28a vector, with NdeI and XhoI as restriction sites; S2) The ligation product of S1) was transformed into BL21(DE3) competent bacteria for transformation; S3) Recombinant protein expression: Single colonies with correct band sequences as identified by PCR and sequencing were inoculated into LB liquid medium containing kanamycin and cultured until OD. 600 =0.6~0.8, use IPTG to induce, collect the bacterial cells by centrifugation, lyse at low temperature and collect the protein supernatant by centrifugation; S4) Recombinant protein purification: The protein supernatant is purified by affinity chromatography and the elution peak is collected to obtain the antibody protein.

[0035] This preparation method To more concisely and clearly demonstrate the technical solution, purpose, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0036] Example 1: Establishment of an antibody library combining human immunoglobulin G (IgG) and alpaca phage

[0037] A simplified outline of the alpaca phage antibody library was established based on CN114316051A. S1) Human IgG was used to immunize alpacas with a mixture of four IgG isoforms (Abcam) in equal proportions, and peripheral blood mononuclear cells (PBMCs) were collected. S2) RNA was extracted from PBMCs and reverse transcribed into cDNA; S3) After PCR amplification of the target sequence, it is ligated into the phage vector pHIAT-1 through HindIII and NotI restriction sites, and then transformed into E. coli TG1 to form the original phage library. S4) Add helper phage M13K07 to TG1 strain that has grown to the logarithmic phase, incubate overnight, and then collect the supernatant by centrifugation; S5) Phage particles were precipitated using PEG, then resuspended in PBS and sterilized by filtration through a 0.45 μm filter to obtain the phage VHH antibody library with a capacity of 4.6 × 10⁻⁶. 13 .

[0038] Example 2: Phage Library Screening

[0039] (1) First round of screening for phage antibodies S1) The titer of the helper phage M13K07 was 1.2 × 10⁻⁶. 10 pfu / mL, TG1 was infected with helper phage M13K07; S2) Coat human IgG on ELISA plates at 0.5 µg / well, incubate overnight at 4°C, and wash the plates 3 times; S3) Prepare 5% skim milk powder (blocking solution) using PBST and block the plate at 200 µL / well. Incubate at 37°C for 2 h and wash the plate 3 times. S4) Add 100 µL of phage library solution to each well, incubate at 37°C for 2 h, and wash the plate 3 times; S5) Add 100 µL of Glycine-HCl buffer to each well, shake gently at room temperature for 10 min, then aspirate the elution buffer and quickly add 80 μL of 1 M Tris-HCl buffer; take out 10 μL for titer determination, add the remaining liquid to 5 mL of TG1 bacterial culture that has grown to the logarithmic phase, and incubate at 37°C for 30 min. S6) Add 2 × YT medium to a total volume of 10 mL, and incubate at 37℃ and 220 rpm for 30 min-1 h; S7) Add ampicillin (Amp) to a final concentration of 100 μg / mL, and incubate the bacterial culture at 37℃ and 250 rpm until OD reaches 100 μg / mL. 600 =0.4-0.6; S8) Add helper phage M13KO7 to the bacterial culture, let it stand at 37℃ for 30 min, and then incubate at 37℃ and 250 rpm for 45 min-1 h; S9) Centrifuge at 4℃ and 5000 rpm for 20 min, discard the supernatant, resuspend the cells in an equal volume of 2 × YT-Amp-kana (kanamycin) medium (containing 100 μg / mL Amp and 30 μg / mL kana), and incubate overnight at 30℃ and 220 rpm. S10) Centrifuge at 8000 rpm for 20 min at 4℃, take the supernatant and add 1 / 5 volume of 20% PEG / NaCl solution, mix thoroughly, and let stand on ice or at 4℃ for 1-2 h. S11) Centrifuge at 4℃ and 8000 rpm for 30 min, discard the supernatant, resuspend the precipitate in 1 mL of sterile PBS, and then centrifuge at 4℃ and 8000 rpm for 10 min. The precipitate is the phage antibody particles.

[0040] (2) Second round of screening for phage antibodies S1) Coat human IgG on an ELISA plate at 1 µg / well, incubate overnight at 4°C, and wash the plate 6 times. S2) Block the plate using blocking solution, 200 µL / well, incubate at 37°C for 2 h, and wash the plate 6 times; S3) Add 100 µL of the phage library solution from the first round of screening to each well, incubate at 37°C for 2 h, and wash the plate 6 times; The remaining operations are the same as the first round of screening.

[0041] (3) Third round of screening for polyclonal phage antibodies Human IgG was coated onto ELISA plates at 0.1 µg / well and incubated overnight at 4°C. The plates were washed 3 times. Blocking buffer was applied at 200 µL / well and incubated at 37°C for 2 h. The plates were washed 3 times. 100 µL of the phage library solution from the second round of screening was added to each well and incubated at 37°C for 2 h. The plates were washed 10 times. The remaining procedures were the same as in the first round of screening.

[0042] (4) Monoclonal phage detection S1) The phages selected in the third round of screening were used to infect TG1, diluted and spread on plates for culture, and then 96 single clones were picked. S2) Using the original library as a negative control, ELISA was performed to select ODs. 450 Clones with a value greater than 2.1 times that of the original library were considered preliminary positive clones and were sequenced. S3) Based on the sequencing results, after removing repetitive sequences, five sequences with better IgG adsorption effects were selected as candidate sequences. The amino acid sequences of the five sequences are shown in SEQ ID NO.1 to SEQ ID NO.5, respectively.

[0043] The structure and function of the five single-chain antibodies selected through screening were analyzed, and the results are as follows: SEQ ID NO: 1: MQVQLQESGGGLVQPGGSLRLSCVPSGRTFSTYAMAWHRQAPGKQRELVASITSDGSTNYADSVKARFTISRDNAKNTVYLQMNSLKPEDTAVYYCAGRFLGYASSNAYHEALYNYDYWGQGTQVTVSS Wherein, CDR1: TYAMA (SEQ ID NO: 6), CDR2: SITSDGSTNYADSVKA (SEQ ID NO: 7), CDR3: RFLGYASSNAYHEALYNYDY (SEQ ID NO: 8); FR1: QVQLQESGGGLVQPGGSLRLSCVPSGRTFS(SEQ ID NO: 9), FR2: WHRQAPGKQRELVA (SEQ ID NO: 10), FR3: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAG (SEQ ID NO: 11), FR4: WGQGTQVTVSS (SEQ ID NO: 12).

[0044] SEQ ID NO: 2: MQVQLQESGGGLVQAGGSLRLSCAVSGNTLSRYAMGWFRQAPGKEREFVGSIRWNNGNTYLVDSVKGRFTISGDNAHDTVHLQMTSLKPEDTGVYFCVARSFGTGQWDYWGQGTQVTVSS Wherein, CDR1: RYAMG (SEQ ID NO: 13), CDR2: SIRWNNGNTYLVDSVKG (SEQ ID NO: 14), CDR3: RSFGTGQWDY (SEQ ID NO: 15); FR1: QVQLQESGGGLVQAGGSLRLSCAVSGNTLS (SEQ ID NO: 16), FR2: WFRQAPGKEREFVG (SEQ ID NO: 17), FR3: RFTISGDNAHDTVHLQMTSLKPEDTGVYFCVA(SEQ ID NO: 18), FR4: WGQGTQVTVSS (SEQ ID NO: 12).

[0045] SEQ ID NO: 3: MQVQLQESGGGLVQPGESLRLSCAASPRTFSVYAMGWYRQAPGKQRELVATIRWNNAATNYADSVKGRFTISRDNAKDTLYLQMNSLKPEDTAVYYCNAQNSWRNIWGQGTQVTVSS wherein, CDR1: VYAMG (SEQ ID NO: 19), CDR2: TIRWNNAATNYADSVKG (SEQ ID NO: 20), CDR3: QNSWRNI (SEQ ID NO: 21); FR1: QVQLQESGGGLVQPGESLRLSCAASPRTFS (SEQ ID NO: 22), FR2: WYRQAPGKQRELVA (SEQ ID NO: 23), FR3: RFTISRDNAKDTLYLQMNSLKPEDTAVYYCNA (SEQ ID NO: 24), FR4: WGQGTQVTVSS (SEQ ID NO: 12).

[0046] SEQ ID NO: 4: MQVQLQESGGGLVQAGGSLRLSCAVSGIAFEVFNMGWFRQAPGNEREFVAAANWKSGSTYYADSVKGRFTISRDSAKNTVYLQMNSLQPEDTAVYYCASRFLPYASSNAYHEALYNYDYWGQGTQVTVSS wherein, CDR1: VFNMG (SEQ ID NO: 25), CDR2: AANWKSGSTYYADSVKG (SEQ ID NO: 26), CDR3: RFLPYASSNAYHEALYNYDY (SEQ ID NO: 27); FR1: QVQLQESGGGLVQAGGSLRLSCAVSGIAFE (SEQ ID NO: 28), FR2: WFRQAPGNEREFVA (SEQ ID NO: 29), FR3: RFTISRDSAKNTVYLQMNSLQPEDTAVYYCAS (SEQ ID NO: 30), FR4: WGQGTQVTVSS (SEQ ID NO: 12).

[0047] SEQ ID NO: 5: MQVQLQESGGGLVQAGGSLRLSCAVSGNTLSQYAMGWFRQAPGNEREFVAAIRRSGGSTYYADSVEGRFTISRDSAKNTVYLQMNSLQPEDTAVYYCAAGGRDTYGYKLPTTRVDYWGQGTQVTVSS Among them, CDR1: QYAMG (SEQ ID NO: 31), CDR2: AIRRSGGSTYYADSVEG (SEQ ID NO: 32), CDR3: GGRDTYGYKLPTTRVDY (SEQ ID NO: 33); FR1: QVQLQESGGGLVQAGGSLRLSCAVSGNTLS (SEQ ID NO: 16), FR2: WFRQAPGNEREFVA (SEQ ID NO: 29), FR3: RFTISRDSAKNTVYLQMNSLQPEDTAVYYCAA (SEQ ID NO: 34), FR4: WGQGTQVTVSS (SEQ ID NO: 12).

[0048] Example 3: In vitro recombinant expression and purification of antibodies

[0049] S1) After the pET-28a vector was double-digested with NdeI and XhoI, the nucleotide sequences corresponding to the amino acid sequences shown in SEQ ID NO.1 to 5 were ligated to the pET-28a vector through the NdeI and XhoI restriction sites. S2) The ligation product was transformed into BL21(DE3) competent bacteria for further transformation; S3) After selecting single-clone colonies for PCR and sequencing to confirm the correct band sequence, recombinant protein expression is performed: S4) Streak the bacterial culture on plates, pick single colonies and inoculate them into LB liquid medium containing kanamycin, then expand the culture at a 1:100 ratio to OD. 600 =0.6-0.8, add IPTG to a final concentration of 1 mM and induce for 6 h, centrifuge to collect bacterial cells, then lyse at low temperature and centrifuge to collect protein supernatant; S5) Purification of recombinant protein: The supernatant protein after lysing and centrifugation is filtered through a 0.45 μm filter membrane and then purified by affinity chromatography (Ni ion chelating packing with His tag); the chromatography column is equilibrated with 20 mM Tris-HCl buffer, and then the protein is slowly added to the chromatography column. The protein is washed with 10 mM imidazole buffer and 40 mM imidazole buffer respectively, and then eluted with 250 mM imidazole buffer. The elution peak is collected to obtain alpaca single-domain antibody protein.

[0050] The purity of the target protein can be determined by performing a 15% SDS-PAGE gel analysis on the elution peak.

[0051] Example 4: Detection of the binding activity of single-domain antibodies against human IgG

[0052] S1) Add coating buffer (containing equal proportions of IgG1, IgG2, IgG3, IgG4 and IgG subtypes) to each ELISA plate (96-well plate), with the concentration diluted to 1 μg / mL, 100 μL per well, and incubate at 37°C for 2 h. S2) Discard the coating buffer, add blocking buffer (5% BSA) 200 μL per well, incubate overnight at 4°C, and wash 5 times. Add serially diluted single-domain antibodies to wells coated with the five different coating buffers. Additionally, add serially diluted protein A to wells coated with a mixture of four IgG subtypes in equal proportions. The serial dilution concentrations are 15.625, 31.25, 62.5, 125, 250, 500, and 1000 pg / mL, 100 μL per well. Incubate at room temperature for 2 hours, and wash 5 times. Add antibodies containing anti-His and HRP tags (antibody dilution ratio 1:5000), 100 μL per well, incubate at room temperature for 1 hour, and wash 5 times. S3) Add 100 μL of two-component TMB colorimetric solution to each well and incubate at room temperature in the dark for 5-10 min. Remove the ELISA plate after color development and add 100 μL of 1M H2SO4 stop solution to each well. Measure the absorbance at 450 nm using a microplate reader.

[0053] The results are as follows Figure 1-6 As shown in the figure. The results indicate that all five single-domain antibodies can bind to all four subtypes of human IgG, and the binding activity gradually increases with increasing concentration, with the highest binding activity against IgG1 and IgG4 subtypes. In addition, the single-domain antibodies numbered SEQ ID NO.1, SEQ ID NO.3, SEQ ID NO.4 and SEQ ID NO.5 have higher binding activity against IgG than protein A, while the binding activity of protein A and SEQ ID NO.2 against IgG is basically equivalent.

[0054] Example 5: Synthesis of Immunosorbents

[0055] S1) Add 10 mL of activation reaction solution (sodium borohydride: 0.02 g, NaOH: 0.24 g) and 10 mL of BDGE to 10 mL of agarose (Bestarose 6FF) packing material. Activate at 37℃ and 120 rpm for about 2.5 h. Then wash until the pH is 5.0-7.0 and vacuum dry. S2) Add 10 mL of coupling buffer (ammonium sulfate: 3.96 g; NaOH: 0.27 g) and 10 mL of the prepared alpaca single-domain antibody solution to the packing material dried in step S1). Perform the coupling reaction at 37°C and 120 rpm for about 8 h. Then wash more than 10 times and dry. S3) Add 20 mL of 1 M ethanolamine solution to the packing material that was dried in step S2), and perform end-capping reaction at 37°C and 120 rpm overnight. Then wash more than 10 times and dry the packing material. Add 20% ethanol and store for later use.

[0056] Example 6: Determination of the adsorption performance of immunosorbents for human IgG

[0057] Referring to the method described in Example 5 of CN111057153A, the adsorption performance of human IgG was tested using a static adsorption method. The brief steps are as follows: S1) The immunoadsorbent was prepared according to the above method. 10 mL of human plasma was added to 1 mL of immunoadsorbent and placed in a shaker. The mixture was slowly shaken at room temperature for 1 h. S2) After the reaction is complete, the above reaction solution is added to a disposable affinity chromatography column. First, it is washed with about 100 mL of equilibration buffer (PBS), and then eluted with 40 mL of elution buffer (citric acid 2.1 g / L, NaCl 8.0 g / L). The elution peak is collected, and the OD280 value is detected by UV. The adsorption performance (mg / mL) = [(OD280 / 1.38) × 40] / 1; S3) Use a biochemical analyzer to detect the content of immunoglobulins IgA and IgM in plasma and determine the non-specific adsorption amount.

[0058] The results are shown in Table 1.

[0059] Table 1. Detection of the adsorption performance of immunoadsorbents for various immunoglobulins SEQ ID NO.1 58 1.70 1.97 SEQ ID NO.2 49 1.82 1.93 SEQ ID NO.3 45 1.60 2.01 SEQ ID NO.4 54 1.64 1.86 SEQ ID NO.5 56 1.71 1.89 As shown in Table 1, the immunoadsorbents formed by the coupling of the five single-domain antibodies with the solid-phase carrier have high adsorption performance for human IgG. Among them, the protein with SEQ ID NO.1 has the highest adsorption performance. The overall difference is not very large. Moreover, all five immunoadsorbents have low non-specific adsorption of IgA and IgM and good specificity.

[0060] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. An antibody against human IgG protein, comprising a framework region FR1-FR4 and an antigen-binding region CDR1-CDR3, characterized in that, The amino acid sequences of CDR1 to CDR3 are as follows: CDR1: RYAMG, CDR2: SIRWNNGNTYLVDSVKG, CDR3: RSFGTGQWDY.

2. The antibody according to claim 1, characterized in that, The amino acid sequences of FR1 to FR4 are as follows: FR1: QVQLQESGGGLVQAGGSLRLSCAVSGNTLS, FR2: WFRQAPGKEREFVG, FR3: RFTISGDNAHDTVHLQMTSLKPEDTGVYFCVA, FR4: WGQGTQVTVSS.

3. The antibody according to claim 1 or 2, characterized in that, Its preparation methods include: S1) The nucleotide sequence corresponding to the antibody is linked to the pET-28a vector, with NdeI and XhoI as restriction sites; S2) The ligation product of S1) was transformed into BL21(DE3) competent bacteria for transformation; S3) Recombinant protein expression: Single colonies with correct band sequences as identified by PCR and sequencing were inoculated into LB liquid medium containing kanamycin and cultured until OD. 600 =0.6~0.8, use IPTG to induce, collect the bacterial cells by centrifugation, lyse at low temperature and collect the protein supernatant by centrifugation; S4) Recombinant protein purification: The protein supernatant is purified by affinity chromatography and the elution peak is collected to obtain the antibody protein.

4. An immunoadsorbent comprising a solid-phase support, characterized in that, The antibody described in any one of claims 1 to 3 is coupled to the surface of the solid-phase support.

5. The immunoadsorbent according to claim 4, characterized in that, The solid support is selected from at least one of agarose, chitosan, dextran gel, resin and cellulose microspheres.

6. The use of the antibody according to any one of claims 1 to 3 in the preparation of IgG immunosorbent.

7. The use of the antibody according to any one of claims 1 to 3 in the preparation of immunoglobulin IgG purification agent.

8. The application according to claim 6 or 7, characterized in that, The IgG is selected from at least one of the IgG1, IgG2, IgG3 and IgG4 subtypes.

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