Igm antibody, preparation method therefor and use thereof

Abstract

The present invention relates to the field of biotechnology, and provides an IgM antibody, a preparation method therefor and a use thereof. The provided rheumatoid factor IgM (RF IgM) antibody can specifically recognize an FC fragment of denatured IgG, can be used as a raw material of a quality control product of an RF detection reagent, can improve the screening efficiency of the raw material, reduce the difficulty of batch-to-batch difference control of the raw material, and improve the sensitivity and accuracy of detection. The antibody can be used in an RF IgM detection kit, has good specificity and stability, facilitates clinical operations, greatly saves costs, and greatly controls the batch-to-batch difference between quality control products.

Description

IgM antibodies, their preparation methods, and applications

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510496078.5, filed on April 18, 2025, entitled "IgM Antibody and Preparation Method Thereof and Application", which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of biotechnology, and in particular to an IgM antibody, its preparation method, and its application. Background Technology

[0004] Rheumatoid arthritis (RA) is a systemic autoimmune disease of unknown etiology, characterized by symmetrical, polyarticular, chronic proliferative synovitis. Recurrent attacks lead to progressive destruction of the affected joints and surrounding tissues, often resulting in joint deformities and functional impairments. It can also cause damage to target organs and systems such as the heart, kidneys, eyes, respiratory system, and hematopoietic system. The prevalence of RA is close to 1%, highest in middle-aged women. It is the most widespread immune-mediated inflammatory joint disease in the world and has gradually become one of the leading causes of loss of labor force and disability in China.

[0005] Rheumatoid factor (RF) is an autoantibody that targets the FC fragment of denatured IgG. RF binds to denatured IgG in the body to form immune complexes, which can activate complement or be phagocytosed by phagocytes. Lysosomal enzymes, activated peptides, collagenases, prostaglandin E2, and other substances released by phagocytes, along with cytokines and inflammatory adhesion molecules, cause inflammatory damage to tissues, leading to osteoarthritis and vasculitis. RF is primarily 19S IgM, but 7S IgG and IgA are also present. IgM is considered an important serological marker for RA diagnosis; an IgM titer >80 IU / mL accompanied by severe joint dysfunction usually indicates a poor prognosis. However, the level of IgM RF is not closely related to the activity of RA. IgG RF levels are closely related to synovitis, vasculitis, and extra-articular symptoms in RA patients; detection of IgG RF in synovial fluid is more significant than in serum. IgA RF is an indicator of clinical activity in RA and is significantly correlated with bone destruction. Reports indicate that IgG RF and IgA RF exhibit certain patterns in the serum of RA patients. The presence of IgG RF and IgA RF is always accompanied by an increase in IgM RF levels. The presence of IgM RF alone often indicates a better prognosis, while the elevation of multiple RF subtypes indicates a poor prognosis.

[0006] Currently, commonly used methods for detecting RA include latex agglutination, enzyme-linked immunosorbent assay (ELISA), and immunoturbidimetry. Latex agglutination was once widely used due to its simplicity and ease of execution. This method primarily detects IgM RF, but IgG RF is difficult to detect using this method. However, this method is easily affected by factors such as blood lipids, has many interfering factors, poor repeatability, and can only perform qualitative or semi-quantitative measurements, exhibiting significant limitations and defects in the diagnosis of RA. Immunoturbidimetry has the advantages of high sensitivity, good repeatability, fast reaction speed, and ease of automation and standardization. ELISA can determine RF subtypes, aiding in disease prognosis.

[0007] In the current field of RF in vitro diagnostic kits, quality control products are mainly derived from high-value clinical serum, which is extremely difficult to collect, batch-to-batch variations are hard to control, and there are no commercially available specific recombinant antibodies for reference, which has seriously affected the production of RF quality control products.

[0008] In view of the above, this application is hereby submitted. Summary of the Invention

[0009] The primary objective of this application is to provide a rheumatoid factor IgM antibody to solve the aforementioned technical problems.

[0010] The second objective of this application is to provide a biological material.

[0011] A third objective of this application is to provide a modified rheumatoid factor IgM antibody.

[0012] The fourth objective of this application is to provide an antibody composition.

[0013] The fifth objective of this application is to provide the use of the above-mentioned rheumatoid factor IgM antibody, or biological material, or modified rheumatoid factor IgM antibody, or antibody composition.

[0014] The sixth objective of this application is to provide a rheumatoid factor detection kit.

[0015] The seventh objective of this application is to provide a pharmaceutical composition.

[0016] To achieve the above objectives, the following technical solution is adopted:

[0017] In a first aspect, this application provides a rheumatoid factor IgM antibody selected from antibodies RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF-422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018, or RF-H0068;

[0018] The antibody RF-70 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.1, 211, and 2, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.3 to 5, respectively.

[0019] The antibody RF-91 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 6, 212, and 7, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 8 to 10, respectively.

[0020] The antibody RF-920 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.11, 213, and 12, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.13-15.

[0021] The antibody RF-972 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.16, 214, and 17, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.18-20.

[0022] The antibody RF-1029 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.21, 215, and 22, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.23-25.

[0023] The antibody RF-1072 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.26, 216, and 27, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.28-30.

[0024] The antibody RF-307 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.31, 217, and 32, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.33-35.

[0025] The antibody RF-309 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.36, 218, and 37, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.38-40.

[0026] The antibody RF-332 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.41, 219, and 42, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.43-45, respectively.

[0027] The antibody RF-341 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.46, 220, and 47, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.48-50, respectively.

[0028] The antibody RF-346 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 51, 221, and 52, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 53-55.

[0029] The antibody RF-350 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 56, 222, and 57, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 58-60.

[0030] The antibody RF-356 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 61, 223, and 62, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 63-65.

[0031] The antibody RF-384 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 66, 224, and 67, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 68-70.

[0032] The antibody RF-417 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.71, 225, and 72, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.73-75, respectively.

[0033] The antibody RF-422 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.76, 226, and 77, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.78-80.

[0034] The antibody RF-431 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 81, 227, and 82, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 83-85.

[0035] The antibody RF-434 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 86, 228, and 87, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 88-90.

[0036] The antibody RF-450 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 91, 229, and 92, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 93-95.

[0037] The antibody RF-451 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 96, 230, and 97, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 98-100.

[0038] The antibody RF-455 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 101, 231, and 102, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 103-105.

[0039] The antibody RF-478 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 106, 232, and 107, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 108-110.

[0040] The antibody RF-628 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 111, 233, and 112, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 113-115.

[0041] The antibody RF-766 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 116, 234, and 117, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 118-120.

[0042] The antibody RF-777 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 121, 235, and 122, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 123-125.

[0043] The antibody RF-950 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 126, 236, and 127, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 128-130.

[0044] The antibody RF-H0002 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 131, 237, and 132, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 133-135.

[0045] The antibody RF-H0014 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 136, 238, and 137, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 138-140.

[0046] The antibody RF-H0018 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 141, 239, and 142, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 143-145.

[0047] The antibody RF-H0068 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 146, 240, and 147, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 148-150.

[0048] As a further technical solution, the antibody RF-70 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the same amino acid sequence as the one shown in SEQ ID NO. 151, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the same amino acid sequence as the one shown in SEQ ID NO. 152.

[0049] The antibody RF-91 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 153, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 154.

[0050] The antibody RF-920 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 155, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 156.

[0051] The antibody RF-972 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 157 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 158.

[0052] The antibody RF-1029 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 159, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 160.

[0053] The antibody RF-1072 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the same amino acid sequence as shown in SEQ ID NO. 161, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the same amino acid sequence as shown in SEQ ID NO. 162.

[0054] The antibody RF-307 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 163, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 164.

[0055] The antibody RF-309 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 165 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 166.

[0056] The antibody RF-332 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 167, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 168.

[0057] The antibody RF-341 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 169, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 170.

[0058] The antibody RF-346 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 171, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 172.

[0059] The antibody RF-350 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 173, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 174.

[0060] The antibody RF-356 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 175, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 176.

[0061] The antibody RF-384 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 177, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 178.

[0062] The antibody RF-417 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 179, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 180.

[0063] The antibody RF-422 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 181 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 182.

[0064] The antibody RF-431 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 183, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 184.

[0065] The antibody RF-434 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 185 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 186.

[0066] The antibody RF-450 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 187 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 188.

[0067] The antibody RF-451 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 189, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 190.

[0068] The antibody RF-455 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 191, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 192.

[0069] The antibody RF-478 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 193, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 194.

[0070] The antibody RF-628 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 195, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 196.

[0071] The antibody RF-766 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 197 and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 198.

[0072] The antibody RF-777 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 199, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 200.

[0073] The antibody RF-950 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 201, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 202.

[0074] The antibody RF-H0002 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 203, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 204.

[0075] The antibody RF-H0014 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 205, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 206.

[0076] The antibody RF-H0018 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 207, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 208.

[0077] The antibody RF-H0068 has a light chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 209, and a heavy chain variable region having more than 80% (e.g., 80%, 82%, 85%, 87%, 89%, 90%, 91%, 92%, 93%, 95%, 97%, 98%, or 99%) of the amino acid sequence shown in SEQ ID NO. 210.

[0078] As a further technical solution, the heavy chain constant region of the rheumatoid factor IgM antibody is selected from the human IgM constant region.

[0079] As a further technical solution, the light chain constant region of the rheumatoid factor IgM antibody is selected from the human κ chain constant region and the human λ chain constant region.

[0080] Secondly, this application provides biological materials selected from any one of a to c:

[0081] a. Nucleotides, wherein the nucleotides comprise the nucleotide sequence of the rheumatoid factor IgM antibody;

[0082] b. A carrier carrying the nucleotides in a;

[0083] c. A cell carrying the nucleotides in a, or containing the vector in b, or expressing the rheumatoid factor IgM antibody.

[0084] Thirdly, this application provides a modified rheumatoid factor IgM antibody, which is obtained by modifying the aforementioned rheumatoid factor IgM antibody;

[0085] The modifications include antibody-engineered modifications and chemical modifications;

[0086] The antibody engineering modifications include affinity maturation modification, subtype switching modification, bispecific antibody modification, glycosylation modification, fusion protein modification, disulfide bond optimization modification, and surface charge optimization modification.

[0087] The chemical modifications include polyethylene glycol modification, drug coupling modification, and labeling modification.

[0088] Fourthly, this application provides an antibody composition comprising one or more of the following: RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF-422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018, or RF-H0068.

[0089] Fifthly, this application provides the use of the above-mentioned rheumatoid factor IgM antibody, or biological material, or modified rheumatoid factor IgM antibody, or antibody composition in any of the following:

[0090] (I) Prepare products for detecting rheumatoid factor;

[0091] (II) Used for the diagnosis of autoimmune diseases;

[0092] (III) Preparation of quality control products for rheumatoid factor;

[0093] (IV) Used to treat autoimmune diseases;

[0094] Optionally, the autoimmune disease includes one or more of the following: rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, dermatomyositis, scleroderma, mononucleosis, hepatitis, influenza, tuberculosis, bacterial endocarditis, malaria, schistosomiasis, or tumor.

[0095] Sixthly, this application provides a rheumatoid factor detection kit, comprising the rheumatoid factor IgM antibody, or the modified rheumatoid factor IgM antibody, or the antibody composition.

[0096] In a seventh aspect, this application provides a pharmaceutical composition comprising the rheumatoid factor IgM antibody, or the modified rheumatoid factor IgM antibody, or the antibody composition.

[0097] Compared with the prior art, this application has the following beneficial effects:

[0098] 1. The rheumatoid factor IgM antibody (RF-IgM antibody) provided in this application can specifically recognize the FC fragment of denatured IgG, has good stability, and can be used as a raw material for the quality control of RF detection reagents, which greatly improves the screening efficiency of raw materials and significantly reduces the difficulty of batch-to-batch variation control of raw materials.

[0099] 2. This application utilizes RF-IgM antibody as a raw material for the quality control of RF detection reagents, thereby improving the sensitivity and accuracy of detection.

[0100] 3. The recombinant human RF IgM antibody prepared in this application can be used in RF IgM detection kits. It has good specificity and stability, which not only facilitates clinical operation, but also greatly saves costs and greatly controls the batch-to-batch variation between quality control products. Attached Figure Description

[0101] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0102] Figure 1 shows the electrophoresis results.

[0103] Figure 2 shows the electrophoresis results.

[0104] Figure 3 shows the electrophoresis results. Detailed Implementation

[0105] The implementation schemes of this application will be described in detail below with reference to the embodiments and examples. However, those skilled in the art will understand that the following embodiments and examples are only for illustrating this application and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0106] Generally, the nomenclature and techniques used in cell and tissue culture, molecular biology, immunology, microbiology, genetics, and protein and nucleic acid chemistry and hybridization, together with those described herein, are those well-known and commonly used in the art. Unless otherwise stated, the methods and techniques of this application are generally performed according to conventional methods well-known in the art and described in various general and more specific references, which are cited and discussed throughout this specification. Enzymatic reactions and purification techniques are performed according to the manufacturer's instructions, as commonly practiced in the art, or as described herein. The nomenclature, laboratory procedures, and techniques used in analytical chemistry, synthetic organic chemistry, and medical and medicinal chemistry, together with those described herein, are those well-known and commonly used in the art.

[0107] The "variable region" or "variable domain" of an antibody refers to the domain at the amino terminus of the antibody's heavy or light chain that recognizes and binds to antigens. The composition and arrangement of the amino acids in this region determine the antibody's specificity in recognizing antigens. The heavy chain variable region can be called "VH," and the light chain variable region can be called "VL." These domains are usually the most variable parts of the antibody and contain antigen-binding sites. The variable regions of both the heavy and light chains consist of three complementarity-determining regions (CDRs) (also known as hypervariable regions (HVRs)) connected by four framework regions (FRs). The CDRs in each chain are held tightly together by the FRs to form the variable region. Typically, the VL / VH variable regions of the heavy and light chains are obtained by connecting the following numbered CDRs or HVRs with FRs in the following combination: FR1-CDR1(HVR1)-FR2-CDR2(HVR2)-FR3-CDR3(HVR3)-FR4.

[0108] The term "vector" refers to a nucleic acid delivery vehicle into which nucleotides can be inserted. When a vector enables the expression of a protein encoded by the inserted polynucleotide, it is called an expression vector. Vectors can be introduced into host cells through transformation, transduction, or transfection, allowing the genetic material they carry to be expressed in the host cells.

[0109] The vectors described herein are well-known to those skilled in the art and include, but are not limited to: plasmids; phage particles; Cos plasmids; artificial chromosomes, such as yeast artificial chromosomes (YAC), bacterial artificial chromosomes (BAC), or P1-derived artificial chromosomes (PAC); bacteriophages such as λ phage or M13 phage; and animal viruses. Animal viruses that can be used as vectors include, but are not limited to, retrotranscriptoviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (such as herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, and papillomaviruses. In some embodiments, the vectors described in this application contain regulatory elements commonly used in genetic engineering, such as enhancers, promoters, internal ribosome entry sites (IRES), and other expression control elements (e.g., transcription termination signals, or polyadenylation signals and poly-U sequences, etc.).

[0110] In a first aspect, this application provides a rheumatoid factor IgM antibody selected from antibodies RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF-422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018, or RF-H0068;

[0111] The amino acid sequences of the light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, and the heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH of the above antibodies are as follows:

[0112] In some optional embodiments, the antibody RF-70 has a light chain variable region having more than 80% identical sequence to the amino acid sequence shown in SEQ ID NO.151 and a heavy chain variable region having more than 80% identical sequence to the amino acid sequence shown in SEQ ID NO.152.

[0113] The antibody RF-91 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.153 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.154;

[0114] The antibody RF-920 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.155 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.156;

[0115] The antibody RF-972 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.157 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.158;

[0116] The antibody RF-1029 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.159 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.160;

[0117] The antibody RF-1072 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.161 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.162;

[0118] The antibody RF-307 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.163 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.164;

[0119] The antibody RF-309 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.165 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.166;

[0120] The antibody RF-332 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.167 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.168;

[0121] The antibody RF-341 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.169 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.170;

[0122] The antibody RF-346 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.171 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.172;

[0123] The antibody RF-350 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.173 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.174;

[0124] The antibody RF-356 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.175 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.176;

[0125] The antibody RF-384 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.177 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.178;

[0126] The antibody RF-417 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.179 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.180;

[0127] The antibody RF-422 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.181 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.182;

[0128] The antibody RF-431 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.183 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.184;

[0129] The antibody RF-434 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.185 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.186;

[0130] The antibody RF-450 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.187 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.188;

[0131] The antibody RF-451 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.189 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.190;

[0132] The antibody RF-455 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.191 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.192;

[0133] The antibody RF-478 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.193 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.194;

[0134] The antibody RF-628 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.195 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.196;

[0135] The antibody RF-766 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.197 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.198;

[0136] The antibody RF-777 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.199 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.200;

[0137] The antibody RF-950 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.201 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.202;

[0138] The antibody RF-H0002 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.203 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.204;

[0139] The antibody RF-H0014 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.205 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.206;

[0140] The antibody RF-H0018 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.207 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.208;

[0141] The antibody RF-H0068 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.209 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.210.

[0142] In some alternative embodiments, the heavy chain constant region of the rheumatoid factor IgM antibody is selected from the human IgM constant region.

[0143] In some alternative embodiments, the light chain constant region of the rheumatoid factor IgM antibody is selected from the human κ chain constant region and the human λ chain constant region.

[0144] Secondly, this application provides biological materials selected from any one of a to c:

[0145] a. Nucleotides, wherein the nucleotides comprise the nucleotide sequence of the rheumatoid factor IgM antibody;

[0146] b. A carrier carrying the nucleotides in a;

[0147] c. A cell carrying the nucleotides in a, or containing the vector in b, or expressing the rheumatoid factor IgM antibody.

[0148] Thirdly, this application provides a modified rheumatoid factor IgM antibody, which is obtained by modifying the aforementioned rheumatoid factor IgM antibody;

[0149] The modifications include antibody-engineered modifications and chemical modifications;

[0150] The antibody engineering modifications include affinity maturation modification, subtype switching modification, bispecific antibody modification, glycosylation modification, fusion protein modification, disulfide bond optimization modification, and surface charge optimization modification.

[0151] The chemical modifications include polyethylene glycol modification, drug coupling modification, and labeling modification. The labels include enzymes, fluorescent molecular markers, fluorescent microspheres, colored microspheres, colloidal gold, biotin, or streptavidin, etc.

[0152] Fourthly, this application provides an antibody composition comprising one or more of the following: RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF-422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018, or RF-H0068.

[0153] This antibody composition can be used to detect rheumatoid factor IgM antibodies in quality control samples.

[0154] Fifthly, this application provides the use of the above-mentioned rheumatoid factor IgM antibody, or biological material, or modified rheumatoid factor IgM antibody, or antibody composition in any of the following:

[0155] (I) Prepare products for detecting rheumatoid factor, for example, use the rheumatoid factor IgM antibody of this application as a quality control for the detection of rheumatoid factor;

[0156] (II) Used for the diagnosis of autoimmune diseases;

[0157] (III) Preparation of quality control products for rheumatoid factor;

[0158] (IV) Used to treat autoimmune diseases;

[0159] Optionally, the autoimmune disease includes one or more of the following: rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, dermatomyositis, scleroderma, mononucleosis, hepatitis, influenza, tuberculosis, bacterial endocarditis, malaria, schistosomiasis, or tumor.

[0160] Sixthly, this application provides a rheumatoid factor detection kit, comprising the rheumatoid factor IgM antibody, or the modified rheumatoid factor IgM antibody, or the antibody composition.

[0161] Among them, rheumatoid factor includes IgM type rheumatoid factor. The rheumatoid factor IgM antibody provided in this application can specifically recognize the FC fragment of denatured IgG, has good stability, and can be used in RF IgM detection kits, which not only facilitates clinical operation, but also greatly saves costs and significantly controls batch-to-batch variation between quality control products.

[0162] In a seventh aspect, this application provides a pharmaceutical composition comprising the rheumatoid factor IgM antibody, or the modified rheumatoid factor IgM antibody, or the antibody composition.

[0163] The present application is further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present application in any way.

[0164] Example 1:

[0165] Peripheral blood mononuclear cell cDNA acquisition

[0166] Rubai Biotechnology's autoimmune and allergy PBMC (D001201116) uses TRIzol reagent, following the reagent instructions from 5×10 6 Total RNA was extracted from PBMCs. cDNA was obtained by reverse transcription using 1 μg of RNA and the SuperScript VILO cDNA synthesis kit, following the instructions provided with the kit.

[0167] 65℃ for 5 minutes; then quickly ice bath for at least 1 minute.

[0168] Reverse transcription PCR program

[0169] Oligo(dT)23 reverse transcription parameters:

[0170] Random primer reverse transcription parameters:

[0171] Example 2:

[0172] Construction of human phage library

[0173] Human rheumatoid factor (RF) SCFV primers were mixed in equal proportions to amplify the light chain variable region and heavy chain variable region genes from cDNA. The kit yielded approximately 350 bp bands (VH and VL, both 350 bp) via gel recovery. The SCFV genes were then spliced ​​together according to the following reaction system.

[0174] PCR reaction parameters:

[0175] The PCR products were run on an electrophoresis gel, and the approximately 750 bp fragment was recovered as SCFV. The target fragment SCFV and the vector Pcomb3xss were digested with sfiI, and the Pcomb3xss digestion solution was subjected to CIP treatment. The digestion solution was run on an electrophoresis gel, and the fragments were recovered. The recovered target gene fragment SCFV and the vector Pcomb3xss were ligated, run on an electrophoresis gel, and the ligation product was recovered. The ligation product was transformed into TG1 competent cells, plated on 2YT-AG plates, cultured overnight, and the bacterial culture was collected and stored. The bacterial culture was diluted to 10⁻⁶. -5 10 -6 10 -7 , Coated 2YT-AG plates for overnight culture and detection storage capacity.

[0176] Take 100 μL of bacterial culture and inoculate it into 100 ml of liquid culture medium. Incubate until the OD600 value of the bacterial culture reaches 0.4-0.6. Add the pre-prepared M13K07 at a ratio of 1:20, amplify and culture overnight, precipitate and collect the phage to obtain the phage library.

[0177] Example 3:

[0178] Washing, screening and identification

[0179] Rheumatoid factor (RF) SCFV: Immunotubes were coated with denatured natural IgG antigen, blocked with PBS containing 4% skim milk, and 1x10⁻⁶ ppm was added. 12 The phage library was bound for 1 hour, washed, and then eluted with pH 3 0.15 mol / L Arg-HAC (arginine acetate), 1.6 w / v % peptone, and 1 w / v % yeast extract. It was then eluted again with 50 mmol / L Tris containing 20 mmol / L trypsin. Except for the eluted phages whose titers were measured, all the remaining phages were inoculated into 5 mL of TG1 medium. After standing for 0.5 hours, 20 mL of 2YT-AG medium was added until the OD600 value reached approximately 0.5. Pre-helper phage M13K07 was added at a 1:20 ratio, and the culture was amplified overnight. The phages were then collected as a precipitate. This completed the first round of selection.

[0180] The second, third, and fourth rounds of screening were performed sequentially to enrich high-affinity phage antibodies. Immunosorbents were then coated with various recombinant proteins, and subsequent steps were the same as in the first round of selection.

[0181] Screening for specific antibodies: After the phages from the third round of washing were infecting TG1, they were plated and cultured overnight. Single clones were picked and cultured in 5 96-well 2mL deep-well plates. When the OD600 value of the bacterial culture was around 0.5, the bacterial culture was preserved, and then helper phage M13K07 was added. The culture was incubated at 37℃ for 0.5h and then incubated overnight at 28℃ and 220rpm to induce phage growth.

[0182] The ELISA plate was coated with denatured natural IgG antigen, blocked with PBS containing 4% skim milk, and then 50 μL of phage was added. After washing, diluted anti-M13-HRP antibody was added. TMB staining was performed. Phages showing strong ELISA results were sequenced to obtain the antibody sequence.

[0183] Example 4:

[0184] Construction, expression, and purification of recombinant rheumatoid factor (RF) IgM antibody

[0185] The antibody VH and VL vectors were spliced ​​with the sig-MFc-PCMV3 vector containing the human IgM constant region sequence and the pcdna3.4.2 vector containing the human Cκ constant region sequence, respectively, by PCR. The VL-pCDNA3.2 and VH-sig-MFc-PCMV3 plasmids were co-transfected into 293 cells to obtain RF-IgM expression supernatant. RF-IgM was purified using SPL, and the electrophoresis results are shown in Figures 1, 2, and 3. The purity of all 30 antibody strains was greater than 95%.

[0186] Example 5

[0187] Rheumatoid factor (RF) IgM quality control product potency

[0188] The above 30 RF recombinant antibodies were tested for reactivity using ELISA and then added to recombinant antibody buffer (PBS solution) to prepare quality control samples. The composition is shown in the table below:

[0189] Beckman Coulter kit (catalog number: OSR61105) for antibody titer determination:

[0190] Based on the dilution ratio, the results above show that among the 30 recombinant RF antibodies, RF-346 has the highest antibody titer, at 16915 IU / mL.

[0191] Example 6

[0192] Thermal stability of rheumatoid factor (RF) IgM quality control products

[0193] Thirty RF recombinant antibody quality control samples were diluted to two concentration levels using RF quality control diluent: Level 1 (75 μg / ml) and Level 2 (20 μg / ml). The samples were incubated at 37°C for 10 days. The signal retention rate of the quality control samples was determined using a Beckman Coulter kit (OSR61105). The results are shown in the table below.

[0194] The results in the table show that after 10 days of accelerated heating at 37℃, the signal retention rate of all 30 RF-IgM recombinant antibody quality control samples was greater than 84%, indicating good stability of the quality control samples, which meets clinical requirements and has excellent thermal stability.

[0195] Example 7

[0196] Rheumatoid factor (RF) IgM quality control products are universal across different manufacturers.

[0197] To verify the universality of 30 RF recombinant antibody quality control samples across different manufacturers' kits, five mainstream RF kits were selected for performance testing: Beckman Coulter (OSR61105), Meikang Biotechnology Co., Ltd. (121411), Siemens (OPCE03), Roche Diagnostics (20764574 322), and Antu Biotechnology Co., Ltd. (RF0000A). The 30 RF recombinant antibody quality control samples were diluted to two concentration levels using RF quality control diluent: Level 1 (50 μg / ml) and Level 2 (25 μg / ml), and tested according to the instructions of each of the five RF kits. The results are as follows:

[0198] Note: " / " indicates that this kit was not used for testing.

[0199] Among the five RF IgM detection kits from different manufacturers, Antu, Micon, and Roche used latex immunoturbidimetry, while Beckman and Siemens used scattering turbidimetry. The results in the table above show that the 30 RF recombinant antibody quality control samples exhibited good reactivity in the five RF IgM detection kits, demonstrating highly consistent detection results. This achieves universality across different manufacturers' detection systems, significantly improving the consistency and reliability of the detection results.

[0200] Conclusion: The above 30 recombinant RF-IgM antibodies have been verified to be suitable as quality control samples for RF antibody IgM detection kits (magnetic microparticle chemiluminescence assay). They can also serve as alternative raw materials for the reagent development and optimization of RF antibody detection kits.

[0201] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application. Industrial applicability

[0202] The rheumatoid factor IgM antibody provided in this application can improve the screening efficiency of raw materials, reduce the difficulty of batch-to-batch variation control, and improve the sensitivity and accuracy of detection. The detection kit prepared from this antibody exhibits good specificity and stability. Therefore, the rheumatoid factor IgM antibody of this application has promising prospects for industrial application.

Claims

1. A rheumatoid factor IgM antibody, characterized in that, Selected from antibodies RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF -422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018 or RF-H0068; The antibody RF-70 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.1, 211, and 2, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.3 to 5, respectively. The antibody RF-91 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 6, 212, and 7, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 8 to 10, respectively. The antibody RF-920 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.11, 213, and 12, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.13-15. The antibody RF-972 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.16, 214, and 17, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.18-20. The antibody RF-1029 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.21, 215, and 22, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.23-25. The antibody RF-1072 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.26, 216, and 27, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.28-30. The antibody RF-307 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.31, 217, and 32, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.33-35. The antibody RF-309 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.36, 218, and 37, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.38-40. The antibody RF-332 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.41, 219, and 42, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.43-45, respectively. The antibody RF-341 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.46, 220, and 47, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.48-50, respectively. The antibody RF-346 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 51, 221, and 52, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 53-55. The antibody RF-350 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 56, 222, and 57, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 58-60. The antibody RF-356 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 61, 223, and 62, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 63-65. The antibody RF-384 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 66, 224, and 67, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 68-70. The antibody RF-417 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.71, 225, and 72, respectively, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.73-75, respectively. The antibody RF-422 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO.76, 226, and 77, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO.78-80. The antibody RF-431 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 81, 227, and 82, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 83-85. The antibody RF-434 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 86, 228, and 87, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 88-90. The antibody RF-450 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 91, 229, and 92, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 93-95. The antibody RF-451 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 96, 230, and 97, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 98-100. The antibody RF-455 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 101, 231, and 102, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 103-105. The antibody RF-478 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 106, 232, and 107, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 108-110. The antibody RF-628 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 111, 233, and 112, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 113-115. The antibody RF-766 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 116, 234, and 117, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 118-120. The antibody RF-777 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 121, 235, and 122, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 123-125. The antibody RF-950 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 126, 236, and 127, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 128-130. The antibody RF-H0002 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 131, 237, and 132, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 133-135. The antibody RF-H0014 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL as shown in SEQ ID NO. 136, 238, and 137, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH as shown in SEQ ID NO. 138-140. The antibody RF-H0018 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 141, 239, and 142, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 143-145. The antibody RF-H0068 includes light chain complementarity-determining regions CDR1-VL, CDR2-VL, and CDR3-VL, as shown in SEQ ID NO. 146, 240, and 147, and heavy chain complementarity-determining regions CDR1-VH, CDR2-VH, and CDR3-VH, as shown in SEQ ID NO. 148-150.

2. The rheumatoid factor IgM antibody according to claim 1, characterized in that, The antibody RF-70 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.151 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.152; The antibody RF-91 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.153 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.154; The antibody RF-920 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.155 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.156; The antibody RF-972 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.157 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.158; The antibody RF-1029 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.159 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.160; The antibody RF-1072 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.161 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.162; The antibody RF-307 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.163 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.164; The antibody RF-309 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.165 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.166; The antibody RF-332 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.167 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.168; The antibody RF-341 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.169 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.170; The antibody RF-346 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.171 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.172; The antibody RF-350 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.173 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.174; The antibody RF-356 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.175 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.176; The antibody RF-384 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.177 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.178; The antibody RF-417 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.179 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.180; The antibody RF-422 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.181 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.182; The antibody RF-431 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.183 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.184; The antibody RF-434 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.185 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.186; The antibody RF-450 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.187 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.188; The antibody RF-451 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.189 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.190; The antibody RF-455 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.191 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.192; The antibody RF-478 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.193 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.194; The antibody RF-628 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.195 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.196; The antibody RF-766 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.197 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.198; The antibody RF-777 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.199 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.200; The antibody RF-950 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.201 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.202; The antibody RF-H0002 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.203 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.204; The antibody RF-H0014 has a light chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.205 and a heavy chain variable region having more than 80% identical amino acid sequence to that shown in SEQ ID NO.206; The antibody RF-H0018 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.207 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.208; The antibody RF-H0068 has a light chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.209 and a heavy chain variable region having more than 80% of the same amino acid sequence as the amino acid sequence shown in SEQ ID NO.

210.

3. The rheumatoid factor IgM antibody according to claim 1, characterized in that, The heavy chain constant region of the rheumatoid factor IgM antibody is selected from the human IgM constant region.

4. The rheumatoid factor IgM antibody according to claim 1, characterized in that, The light chain constant region of the rheumatoid factor IgM antibody is selected from the human κ chain constant region and the human λ chain constant region.

5. A biomaterial, characterized in that, The biological material is selected from any one of a to c: a. A nucleotide, wherein the nucleotide comprises a nucleotide sequence encoding a rheumatoid factor IgM antibody according to any one of claims 1 to 4; b. A carrier carrying the nucleotides in a; c. A cell carrying the nucleotides in a, or containing the carrier in b, or expressing the rheumatoid factor IgM antibody according to any one of claims 1 to 4.

6. A modified rheumatoid factor IgM antibody, characterized in that, It is obtained by modification with the rheumatoid factor IgM antibody according to any one of claims 1 to 4; The modifications include antibody-engineered modifications and chemical modifications; The antibody engineering modifications include affinity maturation modification, subtype switching modification, bispecific antibody modification, glycosylation modification, fusion protein modification, disulfide bond optimization modification, and surface charge optimization modification. The chemical modifications include polyethylene glycol modification, drug coupling modification, and labeling modification.

7. An antibody composition, characterized in that, Includes one or more of RF-70, RF-91, RF-920, RF-972, RF-1029, RF-1072, RF-307, RF-309, RF-332, RF-341, RF-346, RF-350, RF-356, RF-384, RF-417, RF-422, RF-431, RF-434, RF-450, RF-451, RF-455, RF-478, RF-628, RF-766, RF-777, RF-950, RF-H0002, RF-H0014, RF-H0018, or RF-H0068 as described in any one of claims 1 to 4.

8. The use of the rheumatoid factor IgM antibody according to any one of claims 1 to 4, or the biomaterial according to claim 5, or the modified rheumatoid factor IgM antibody according to claim 6, or the antibody composition according to claim 7, in any one of the following: (I) Prepare products for detecting rheumatoid factor; (II) Used for the diagnosis of autoimmune diseases; (III) Preparation of quality control products for rheumatoid factor; (IV) Used to treat autoimmune diseases; Optionally, the autoimmune disease includes one or more of the following: rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, dermatomyositis, scleroderma, mononucleosis, hepatitis, influenza, tuberculosis, bacterial endocarditis, malaria, schistosomiasis, or tumor.

9. A rheumatoid factor detection kit, characterized in that, It includes the rheumatoid factor IgM antibody according to any one of claims 1 to 4, or the modified rheumatoid factor IgM antibody according to claim 6, or the antibody composition according to claim 7.

10. A pharmaceutical composition, characterized in that, It includes the rheumatoid factor IgM antibody according to any one of claims 1 to 4, or the modified rheumatoid factor IgM antibody according to claim 6, or the antibody composition according to claim 7.

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