Monoclonal antibody, and method for detecting a1 beta-casein

Abstract

The purpose of the present invention is to provide a monoclonal antibody that binds to A1 beta-casein or to both A1 beta-casein and A2 beta-casein and to provide a method for detecting A1 beta-casein using said monoclonal antibody. The monoclonal antibody according to the present invention is characterized by having a specific antigen complementarity-determining region amino acid sequence.

Description

Monoclonal antibodies and methods for detecting A1 beta-casein The present invention relates to a monoclonal antibody that binds to A1 beta-casein or to both A1 and A2 beta-casein, and to a method for detecting A1 beta-casein using said monoclonal antibody. Milk contains about 3.3% protein, and about 80% of the protein in milk is casein, a phosphoprotein in which phosphoric acid is bound to the side chain hydroxyl group of serine residue. Casein is classified into α type, β type, and κ type, and beta casein is further classified into A1 type and A2 type. Among beta caseins, A1 beta casein is known to be the cause of gas generation, bloating, diarrhea, stomach discomfort, etc. when milk is consumed. Therefore, although it is not yet fully recognized in Japan, the market for A2 milk, which has reduced harm caused by A1 beta casein, has been expanding in Europe and the United States in recent years. Therefore, it is required to measure the content of A1 beta casein in milk. The only difference between A1 beta casein and A2 beta casein is whether the amino acid residue at position 67 is histidine or proline, and the ratio of A1 beta casein to A2 beta casein in milk depends on the difference in the beta casein gene of the cow. That is, cows are divided into those that produce only A1 beta casein, those that produce only A2 beta casein, and those that produce both A1 and A2 beta caseins. Therefore, it is possible to evaluate the proportion of A1 beta-casein in milk by examining the beta-casein gene of cows using the PCR method. However, although the PCR method has high accuracy, it can only test one cow at a time, and cannot test milk products produced from multiple cows. Moreover, testing using the PCR method takes time. Therefore, Patent Document 1 describes a method for determining the amount of A1 beta-casein or A2 beta-casein in a composition by liquid chromatography-mass spectrometry (LC-MS method). The LC-MS method allows for testing of milk products produced from multiple cows. However, the LC-MS method requires specialized and expensive equipment, and is time-consuming and laborious for pre-treatment, etc. As a method for quantifying a target substance, the ELISA method is known, which uses a specific antibody against the target substance in combination with an enzyme reaction. The ELISA method allows testing of milk products instead of individual bovine samples, and is simple and time-saving. ELISA kits for quantifying A1 beta-casein are commercially available (Non-Patent Documents 1 and 2). Special Publication No. 2022-515563 biosensis(R) Bovine A1 Beta Casein ELISA Kit, Catalog No.: BEK-2364-1Pbiosensis(R) Bovine A1 β-Casein ELISA Kit, Catalog Number: BEK-2243-1P / 2P / 5P / 10P As mentioned above, ELISA kits for measuring the amount of A1 beta-casein in milk are commercially available. However, A1 beta-casein in a milk sample containing A2 beta-casein at a ratio of 1 part by mass or more to A1 beta-casein cannot be accurately quantified using the kits because A2 beta-casein inhibits accurate measurement. Therefore, an object of the present invention is to provide a monoclonal antibody that binds to A1 beta-casein or to both A1 beta-casein and A2 beta-casein, and a method for detecting A1 beta-casein using said monoclonal antibody. The present inventors have conducted extensive research to solve the above problems, and as a result have developed a monoclonal antibody that specifically binds to A1 beta-casein or both A1 beta-casein and A2 beta-casein, thereby completing the present invention. The present invention will now be described. [1] A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 301, a heavy chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 302, and a heavy chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 303; and a light chain variable region comprising a light chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 304, a light chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 305, and a light chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 306; A monoclonal antibody characterized by binding to A1 beta-casein. [2] A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 301, a heavy chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 302, and a heavy chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 307; and a light chain variable region comprising a light chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 308, a light chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 309, and a light chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 310; A monoclonal antibody characterized by binding to A1 beta-casein. [3] A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 301, a heavy chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 302, and a heavy chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 311; and a light chain variable region comprising a light chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 312, a light chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 313, and a light chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 314; A monoclonal antibody characterized by binding to A1 beta-casein and A2 beta-casein. [4] The monoclonal antibody according to any one of [1] to [3] above, further comprising an Fc region. [5] A hybridoma comprising a nucleic acid encoding the heavy chain variable region and the light chain variable region of the monoclonal antibody according to any one of [1] to [3]. [6] A method for detecting A1 beta-casein in a milk sample, comprising the steps of: A method comprising the step of mixing the milk sample with the monoclonal antibody described in [1] or [2]. [7] Further, a step of selecting a detection antibody from the monoclonal antibodies according to [1] or [2], and selecting a capture antibody having an epitope different from that of the detection antibody from the monoclonal antibodies according to any one of [1] to [3]; immobilizing the capture antibody on a plate; and The method according to claim 6, further comprising the step of mixing the detection antibody with the mixture of the capture antibody and the milk sample. The monoclonal antibody according to the present invention can specifically bind to A1 beta casein or both A1 beta casein and A2 beta casein. Therefore, the A1 beta casein contained in a milk sample can be easily detected or quantified by the ELISA method using the monoclonal antibody according to the present invention. Therefore, the present invention is industrially very excellent as a technology that can easily evaluate milk by focusing on A1 beta casein, which has been attracting attention in recent years. FIG. 1 is a graph showing the results of quantifying A1 beta casein in a milk sample by sandwich ELISA using the anti-A1 beta casein antibody and anti-A1 / A2 beta casein antibody according to the present invention. FIG. 2 is a graph showing the results of quantifying A1 beta casein in a milk sample by sandwich ELISA using the anti-A1 beta casein antibody according to the present invention. FIG. 3 is a graph showing the results of quantifying A1 beta casein in a milk sample by sandwich ELISA using the anti-A1 beta casein antibody according to the present invention. FIG. 4 is a graph showing the results of quantifying A1 beta casein in a milk sample by sandwich ELISA using the anti-A1 beta casein antibody and anti-A1 / A2 beta casein antibody according to the present invention. FIG. 5 is a graph showing the results of quantifying A1 beta casein in a milk sample by sandwich ELISA using the anti-A1 beta casein antibody and anti-A1 / A2 beta casein antibody according to the present invention. Hereinafter, the anti-A1 beta casein monoclonal antibody obtained by the inventors from rat cells may be referred to as "monoclonal antibody (I)", the anti-A1 beta casein monoclonal antibody obtained from mouse cells as "monoclonal antibody (II)", and the anti-A1 / A2 beta casein monoclonal antibody obtained from rat cells as "monoclonal antibody (III)". The anti-A1 / A2 beta casein monoclonal antibody is an antibody whose antigens are both A1 beta casein and A2 beta casein. In the following sequence definitions, " / " indicates "or", and "deletion" indicates that the amino acid residue may be absent. (1) Monoclonal antibody (I) Monoclonal antibody (I) comprises a heavy chain variable region comprising heavy chain complementarity determining region 1 (VH CDR1) comprising the amino acid sequence of SEQ ID NO: 301, heavy chain complementarity determining region 2 (VH CDR2) comprising the amino acid sequence of SEQ ID NO: 302, and heavy chain complementarity determining region 3 (VH CDR3) comprising the amino acid sequence of SEQ ID NO: 303; and a light chain variable region comprising light chain complementarity determining region 1 (VL CDR1) comprising the amino acid sequence of SEQ ID NO: 304, light chain complementarity determining region 2 (VL CDR2) comprising the amino acid sequence of SEQ ID NO: 305, and light chain complementarity determining region 3 (VL CDR3) comprising the amino acid sequence of SEQ ID NO: 306; and binds to A1 beta casein. SEQ ID NO: 301: Xaa 1 -Xaa 2 -Xaa 3 -Xaa 4 -Xaa 5 -Xaa 6 -Xaa 7 -Xaa 8 Xaa 1 =Gly / Ala, Xaa 2 =Phe / Tyr / Trp / Val / Leu / Ile / Thr / Ser, Xaa 3 =Thr / Ser / Val / Leu / Ile / Pro / Asp / Glu, Xaa 4 =Phe / Tyr / Trp / Val / Leu / Ile, Xaa 5 =Ser / Thr / Arg / Lys / His / Asn / Gln / Asp / Glu, Xaa 6=Asn / Gln / Ser / Thr / Asp / Glu / Arg / Lys / His, Xaa 7 =Tyr / Phe / Trp / Thr / Ser / Lys / Arg / His / Asn / Gln, Xaa 8 =Asp / Glu / Gly / Ala / Thr / Ser / Phe / Tyr / Trp SEQ ID NO: 301 includes SEQ ID NO: 501 below. SEQ ID NO: 501: Xaa 701 -Xaa 702 -Xaa 703 -Xaa 704 -Xaa 705 -Xaa 706 -Xaa 707 -Xaa 708 Xaa 701 =Gly / Ala, Xaa 702 =Phe / Tyr / Trp, Xaa 703 =Thr / Ser, Xaa 704 =Phe / Tyr / Trp, Xaa 705 =Ser / Thr / Arg / Lys / His, Xaa 706 =Asn / Gln / Ser / Thr, Xaa 707 =Tyr / Phe / Trp, Xaa 708 =Asp / Glu / Gly / Ala / Thr / Ser As SEQ ID NO:301, the following SEQ ID NOs:336 to 344 are preferred. SEQ ID NO: 336: Xaa 299 -Xaa 300 -Xaa 301 -Xaa 302 -Xaa 303 -Xaa 304 -Xaa 305 -Xaa 306 Xaa 299 =Gly / Ala, Xaa 300 =Tyr / Phe / Trp, Xaa 301 =Thr / Ser, Xaa 302 =Tyr / Phe / Trp, Xaa 303 =Thr / Ser, Xaa 304 =Asn / Gln, Xaa 305= Tyr / Phe / Trp, Xaa 306 = Asp / Glu Sequence number 337: Xaa 307 - Xaa 308 - Xaa 309 - Xaa 310 - Xaa 311 - Xaa 312 - Xaa 313 - Xaa 314 Xaa 307 = Gly / Ala, Xaa 308 = Tyr / Phe / Trp, Xaa 309 = Thr / Ser, Xaa 310 = Tyr / Phe / Trp, Xaa 311 = Thr / Ser, Xaa 312 = Asn / Gln, Xaa 313 = Tyr / Phe / Trp, Xaa 314 = Gly / Ala Sequence number 338: Xaa 315 - Xaa 316 - Xaa 317 - Xaa 318 - Xaa 319 - Xaa 320 - Xaa 321 - Xaa 322 Xaa 315 = Gly / Ala, Xaa 316 = Tyr / Phe / Trp, Xaa 317 = Thr / Ser, Xaa 318 = Tyr / Phe / Trp, Xaa 319 = Thr / Ser, Xaa 320 = Thr / Ser, Xaa 321 = Tyr / Phe / Trp, Xaa 322 = Gly / Ala Sequence number 339: Xaa 323 - Xaa 324 - Xaa 325 - Xaa 326 - Xaa 327 - Xaa 328 - Xaa 329 - Xaa 330 Xaa 323= Gly / Ala, Xaa 324 = Tyr / Phe / Trp, Xaa 325 = Thr / Ser, Xaa 326 = Tyr / Phe / Trp, Xaa 327 = Lys / Arg / His, Xaa 328 = Asn / Gln, Xaa 329 = Tyr / Phe / Trp, Xaa 330 = Asp / Glu Sequence number 340: Xaa 331 -Xaa 332 -Xaa 333 -Xaa 334 -Xaa 335 -Xaa 336 -Xaa 337 -Xaa 338 Xaa 331 = Gly / Ala, Xaa 332 = Tyr / Phe / Trp, Xaa 333 = Thr / Ser, Xaa 334 = Tyr / Phe / Trp, Xaa 335 = Thr / Ser, Xaa 336 = Thr / Ser, Xaa 337 = Tyr / Phe / Trp, Xaa 338 = Thr / Ser Sequence number 341: Xaa 339 -Xaa 340 -Xaa 341 -Xaa 342 -Xaa 343 -Xaa 344 -Xaa 345 -Xaa 346 Xaa 339 = Gly / Ala, Xaa 340 = Tyr / Phe / Trp, Xaa 341 = Val / Leu / Ile, Xaa 342 = Tyr / Phe / Trp, Xaa 343 = Arg / Lys / His, Xaa 344 = Asn / Gln, Xaa 345 = Tyr / Phe / Trp, Xaa 346 = Gly / Ala Sequence number 342: Xaa347 -Xaa 348 -Xaa 349 -Xaa 350 -Xaa 351 -Xaa 352 -Xaa 353 -Xaa 354 Xaa 347 = Gly / Ala, Xaa 348 = Tyr / Phe / Trp, Xaa 349 = Thr / Ser, Xaa 350 = Tyr / Phe / Trp, Xaa 351 = Thr / Ser, Xaa 352 = Asn / Gln, Xaa 353 = Tyr / Phe / Trp, Xaa 354 = Tyr / Phe / Trp Sequence number 343: Xaa 355 -Xaa 356 -Xaa 357 -Xaa 358 -Xaa 359 -Xaa 360 -Xaa 361 -Xaa 362 Xaa 355 = Gly / Ala, Xaa 356 = Tyr / Phe / Trp, Xaa 357 = Thr / Ser, Xaa 358 = Tyr / Phe / Trp, Xaa 359 = Thr / Ser, Xaa 360 = Asn / Gln, Xaa 361 = Tyr / Phe / Trp, Xaa 362 = Gly / Ala Sequence number 344: Xaa 363 -Xaa 364 -Xaa 365 -Xaa 366 -Xaa 367 -Xaa 368 -Xaa 369 -Xaa 370 Xaa 363 = Gly / Ala, Xaa 364 = Tyr / Phe / Trp, Xaa 365 = Thr / Ser, Xaa366 = Tyr / Phe / Trp, Xaa 367 = Asp / Glu, Xaa 368 = Asp / Glu, Xaa 369 = Tyr / Phe / Trp, Xaa 370 = Gly / Ala SEQ ID NO: 302: Xaa 9 - Xaa 10 - Xaa 11 - Xaa 12 - Xaa 13 - Xaa 14 - Xaa 15 - Xaa 16 Xaa 9 = Ile / Val / Leu / Phe / Tyr / Trp, Xaa 10 = Thr / Ser / Asn / Gln / Lys / Arg / His / Gly / Ala / Tyr / Phe / Trp, Xaa 11 = Thr / Ser / Pro / Tyr / Phe / Trp / Gly / Ala / Asn / Gln / Val / Leu / Ile / Asp / Glu, Xaa 12 = Ser / Thr / Asp / Glu / Lys / Arg / His / Phe / Tyr / Trp / Gly / Ala / Asn / Gln, Xaa 13 = Gly / Ala / Ser / Thr / Asn / Gln / Lys / Arg / His / Asp / Glu, Xaa 14 = Gly / Ala / Ser / Thr / Val / Leu / Ile / Lys / Arg / His, Xaa 15 = Ser / Thr / Tyr / Phe / Trp / Lys / Arg / His / Gly / Ala / Asn / Gln / Val / Leu / Ile / Asp / Glu / Cys / Met, Xaa 16 = Asp / Glu / Gly / Ala / Thr / Ser / Pro / Val / Leu / Ile Examples of SEQ ID NO: 302 include the following SEQ ID NO: 502. SEQ ID NO: 502: Xaa 709 - Xaa 710 - Xaa 711 - Xaa 712 - Xaa 713 - Xaa 714 - Xaa715 -Xaa 716 Xaa 709 = Ile / Val / Leu / Phe / Tyr / Trp, Xaa 710 = Thr / Ser / Asn / Gln, Xaa 711 = Thr / Ser / Pro / Tyr / Phe / Trp, Xaa 712 = Ser / Thr / Asp / Glu, Xaa 713 = Gly / Ala / Ser / Thr, Xaa 714 = Gly / Ala / Ser / Thr, Xaa 715 = Ser / Thr / Tyr / Phe / Trp, Xaa 716 = Asp / Glu / Gly / Ala / Thr / Ser As SEQ ID NO: 302, the following SEQ ID NOS: 345 to 353 are preferred. SEQ ID NO: 345: Xaa 371 -Xaa 372 -Xaa 373 -Xaa 374 -Xaa 375 -Xaa 376 -Xaa 377 -Xaa 378 Xaa 371 = Val / Leu / Ile, Xaa 372 = Thr / Ser, Xaa 373 = Thr / Ser, Xaa 374 = Thr / Ser, Xaa 375 = Gly / Ala, Xaa 376 = Gly / Ala, Xaa 377 = Thr / Ser, Xaa 378 = Thr / Ser SEQ ID NO: 346: Xaa 379 -Xaa 380 -Xaa 381 -Xaa 382 -Xaa 383 -Xaa 384 -Xaa 385 -Xaa 386 Xaa 379 = Val / Leu / Ile, Xaa 380 = Asn / Gln, Xaa 381= Tyr / Phe / Trp, Xaa 382 = Asp / Glu, Xaa 383 = Gly / Ala, Xaa 384 = Thr / Ser, Xaa 385 = Thr / Ser, Xaa 386 = Thr / Ser Sequence No. 347: Xaa 387 - Xaa 388 - Xaa 389 - Xaa 390 - Xaa 391 - Xaa 392 - Xaa 393 - Xaa 394 Xaa 387 = Val / Leu / Ile, Xaa 388 = Thr / Ser, Xaa 389 = Pro, Xaa 390 = Thr / Ser, Xaa 391 = Gly / Ala, Xaa 392 = Gly / Ala, Xaa 393 = Thr / Ser, Xaa 394 = Val / Leu / Ile Sequence No. 348: Xaa 395 - Xaa 396 - Xaa 397 - Xaa 398 - Xaa 399 - Xaa 400 - Xaa 401 - Xaa 402 Xaa 395 = Val / Leu / Ile, Xaa 396 = Asn / Gln, Xaa 397 = Pro, Xaa 398 = Thr / Ser, Xaa 399 = Thr / Ser, Xaa 400 = Gly / Ala, Xaa 401 = Tyr / Phe / Trp, Xaa 402 = Val / Leu / Ile Sequence No. 349: Xaa 403 - Xaa 404 - Xaa 405 - Xaa 406 - Xaa 407-Xaa 408 -Xaa 409 -Xaa 410 Xaa 403 =Val / Leu / Ile, Xaa 404 =Asn / Gln, Xaa 405 =Pro, Xaa 406 =Thr / Ser, Xaa 407 =Thr / Ser, Xaa 408 =Gly / Ala, Xaa 409 =Tyr / Phe / Trp, Xaa 410 =Thr / Ser Sequence number 350: Xaa 411 -Xaa 412 -Xaa 413 -Xaa 414 -Xaa 415 -Xaa 416 -Xaa 417 -Xaa 418 Xaa 411 =Tyr / Phe / Trp, Xaa 412 =Asn / Gln, Xaa 413 =Pro, Xaa 414 =Thr / Ser, Xaa 415 =Thr / Ser, Xaa 416 =Gly / Ala, Xaa 417 =Tyr / Phe / Trp, Xaa 418 =Thr / Ser Sequence number 351: Xaa 419 -Xaa 420 -Xaa 421 -Xaa 422 -Xaa 423 -Xaa 424 -Xaa 425 -Xaa 426 Xaa 419 =Val / Leu / Ile, Xaa 420 =Asn / Gln, Xaa 421 =Thr / Ser, Xaa 422 =Tyr / Phe / Trp, Xaa 423 =Thr / Ser, Xaa 424 =Gly / Ala, Xaa 425 =Asp / Glu, Xaa426 = Thr / Ser Sequence number 352: Xaa 427 - Xaa 428 - Xaa 429 - Xaa 430 - Xaa 431 - Xaa 432 - Xaa 433 - Xaa 434 Xaa 427 = Val / Leu / Ile, Xaa 428 = Thr / Ser, Xaa 429 = Asn / Gln, Xaa 430 = Gly / Ala, Xaa 431 = Gly / Ala, Xaa 432 = Gly / Ala, Xaa 433 = Thr / Ser, Xaa 434 = Thr / Ser Sequence number 353: Xaa 435 - Xaa 436 - Xaa 437 - Xaa 438 - Xaa 439 - Xaa 440 - Xaa 441 - Xaa 442 Xaa 435 = Val / Leu / Ile, Xaa 436 = Thr / Ser, Xaa 437 = Tyr / Phe / Trp, Xaa 438 = Gly / Ala, Xaa 439 = Gly / Ala, Xaa 440 = Arg / Lys / His, Xaa 441 = Thr / Ser, Xaa 442 = Val / Leu / Ile Sequence number 303: Xaa 17 - Xaa 18 - Xaa 19 - Xaa 20 - Xaa 21 - Xaa 22 - Xaa 23 - Xaa 24 - Xaa 25 - Xaa 26 - Xaa 27 - Xaa28 ︁︁ 29 ︁︁ 30 ︁︁ 31 ︁︁ 32 ︁︁ 33 ︁︁ 34 ︁︁ 35 ︁ 36 ︁︁ 37 ︁ 17 The 18 __________________________________________________________________) 19 The 20 לּdPP ‐‟ / llllllllllfold-fled, of affirmation. 21 _____________________________________________________________ 22 _________________________________________) _______________________________________________________________________________________ 23 The 24 _______________________________________________________________________________________ 25 The 26 The 27 The 28 _________________________________________________________________ 29 ___________________________________________________________ 30 $+folderfirm are are are ‐fed toranflâh-flow ‼  l foul- ‼   aphyll   per are with the fallen. 31 = fill  ‐‟ occupation phy‐phy‐phyf‼ her‐לּ‐phyf‐fold filmלּt firm are firms of interest in affirmatively, physician-lations 32 __________________________________________________________ 33 = = of,lasha,aaaaa / latefoldlatefolderfitm are firmxfolderfit‐exiremete-li-li-li-look are with the fall of the singer-li. 34 ___________________________________________________________________________ AA,7 / ﬽‐expresentedlate‼M- ffhan- filled with a ýâ„ declaration ‐flow  gravefigurelfold 35 _____________________________________________________________________. 36= Asp / Glu / Gly / Ala, Xaa 37 = Phe / Tyr / Trp As SEQ ID NO: 303, the following SEQ ID NO: 503 may be mentioned. SEQ ID NO: 503: Xaa 717 -Xaa 718 -Xaa 719 -Xaa 720 -Xaa 721 -Xaa 722 -Xaa 723 -Xaa 724 -Xaa 725 -Xaa 726 -Xaa 727 -Xaa 728 -Xaa 729 -Xaa 730 -Xaa 731 -Xaa 732 -Xaa 733 -Xaa 734 -Xaa 735 -Xaa 736 Xaa 717 = Ala / Gly, Xaa 718 = Arg / Lys / His, Xaa 719 = His / Arg / Lys / deletion, Xaa 720 = Pro / Gly / Ala / Ser T hr, Xaa 721 = Tyr / Phe / Trp, Xaa 722 = Asn / Gln / deletion, Xaa 723 = Asn / Gln / deletion, Xaa 724 = Tyr / Phe / Trp, Xaa 725 = Asp / Glu / deletion, Xaa 726 = Gly / Ala, Xaa 727 = Ser / Thr / Asn / Gln / deletion, Xaa 728 = Tyr / Phe / Trp, Xaa 729 = Tyr / Phe / Trp, Xaa 730 = Tyr / Phe / Trp, Xaa 731 = Gly / Ala / deletion, Xaa 732 = Gly / Ala / deletion, Xaa 733 = Asp / Glu / Ser / Thr / deletion, Xaa 734 = Phe / Tyr / Trp, Xaa735 = Asp / Glu, Xaa 736 = Phe / Tyr / Trp As SEQ ID NO: 303, the following SEQ ID NOS: 315, 316, 354 to 356 are preferred. SEQ ID NO: 315: Xaa 126 -Xaa 127 -Xaa 128 -Xaa 129 -Xaa 130 -Xaa 131 -Xaa 132 -Xaa 133 -Xaa 134 -Xaa 135 -Xaa 136 -Xaa 137 -Xaa 138 -Xaa 139 Xaa 126 = Ala / Gly, Xaa 127 = Arg / Lys / His, Xaa 128 = Pro / Gly / Ala, Xaa 129 = Tyr / Phe / Trp, Xaa 130 = Asn / Gln, Xaa 131 = Asn / Gln, Xaa 132 = Tyr / Phe / Trp, Xaa 133 = Gly / Ala, Xaa 134 = Tyr / Phe / Trp, Xaa 135 = Tyr / Phe / Trp, Xaa 136 = Tyr / Phe / Trp, Xaa 137 = Phe / Tyr / Trp, Xaa 138 = Asp / Glu, Xaa 139 = Phe / Tyr / Trp SEQ ID NO: 316: Xaa 140 -Xaa 141 -Xaa 142 -Xaa 143 -Xaa 144 -Xaa 145 -Xaa 146 -Xaa 147 -Xaa 148 -Xaa 149 -Xaa 150 -Xaa 151 -Xaa152 -Xaa 153 -Xaa 154 -Xaa 155 -Xaa 156 -Xaa 157 Xaa 140 =Ala / Gly, Xaa 141 =Arg / Lys / His, Xaa 142 =His / Arg / Lys, Xaa 143 =Pro / Gly / Ala / Ser T hr, Xaa 144 =Tyr / Phe / Trp, Xaa 145 =Tyr / Phe / Trp, Xaa 146 =Asp / Glu, Xaa 147 =Gly / Ala, Xaa 148 =Ser / Thr / Asn / Gln, Xaa 149 =Tyr / Phe / Trp, Xaa 150 =Tyr / Phe / Trp, Xaa 151 =Tyr / Phe / Trp, Xaa 152 =Gly / Ala, Xaa 153 =Gly / Ala, Xaa 154 =Asp / Glu / Ser / Thr, Xaa 155 =Phe / Tyr / Trp, Xaa 156 =Asp / Glu, Xaa 157 =Phe / Tyr / Trp Sequence No. 354: Xaa 443 -Xaa 444 -Xaa 445 -Xaa 446 -Xaa 447 -Xaa 448 -Xaa 449 -Xaa 450 -Xaa 451 -Xaa 452 -Xaa 453 -Xaa 454 -Xaa 455 -Xaa 456 -Xaa 457 -Xaa 458 -Xaa 459 -Xaa 460 Xaa 443 =Gly / Ala, Xaa444 = His / Arg / Lys, Xaa 445 = His / Arg / Lys, Xaa 446 = Thr / Ser, Xaa 447 = Tyr / Phe / Trp, Xaa 448 = Tyr / Phe / Trp, Xaa 449 = Asp / Glu, Xaa 450 = Gly / Ala, Xaa 451 = Asn / Gln, Xaa 452 = Tyr / Phe / Trp, Xaa 453 = Tyr / Phe / Trp, Xaa 454 = Tyr / Phe / Trp, Xaa 455 = Gly / Ala, Xaa 456 = Gly / Ala, Xaa 457 = Ser T hr, Xaa 458 = Tyr / Phe / Trp, Xaa 459 = Asp / Glu, Xaa 460 = Tyr / Phe / Trp Sequence No. 355: Xaa 461 - Xaa 462 - Xaa 463 - Xaa 464 - Xaa 465 - Xaa 466 - Xaa 467 - Xaa 468 - Xaa 469 - Xaa 470 - Xaa 471 - Xaa 472 - Xaa 473 - Xaa 474 - Xaa 475 - Xaa 476 - Xaa 477 - Xaa 478 Xaa 461 = Gly / Ala, Xaa 462 = His / Arg / Lys, Xaa 463 = His / Arg / Lys, Xaa 464 = Gly / Ala, Xaa 465 = Tyr / Phe / Trp, Xaa 466 = Tyr / Phe / Trp, Xaa 467 = Asp / Glu, Xaa468 = Gly / Ala, Xaa 469 = Ser T hr, Xaa 470 = Tyr / Phe / Trp, Xaa 471 = Tyr / Phe / Trp, Xaa 472 = Tyr / Phe / Trp, Xaa 473 = Gly / Ala, Xaa 474 = Gly / Ala, Xaa 475 = Asp / Glu, Xaa 476 = Tyr / Phe / Trp, Xaa 477 = Asp / Glu, Xaa 478 = Tyr / Phe / Trp Sequence No. 356: Xaa 479 - Xaa 480 - Xaa 481 - Xaa 482 - Xaa 483 - Xaa 484 - Xaa 485 - Xaa 486 - Xaa 487 - Xaa 488 - Xaa 489 Xaa 479 = Ser / Thr, Xaa 480 = His / Arg / Lys, Xaa 481 = Asp / Glu, Xaa 482 = His / Arg / Lys, Xaa 483 = Gly / Ala, Xaa 484 = His / Arg / Lys, Xaa 485 = Tyr / Phe / Trp, Xaa 486 = Val / Leu / Ile, Xaa 487 = Tyr / Phe / Trp, Xaa 488 = Asp / Glu, Xaa 489 = Tyr / Phe / Trp Sequence No. 304: Xaa 38 - Xaa 39 - Xaa 40 - Xaa 41 - Xaa 42 - Xaa 43 - Xaa 44 - Xaa 45 - Xaa 46 - Xaa47 -Xaa 48 Xaa 38 =Gln / Asn / Ser / Thr / Lys / Arg / His, Xaa 39 =Asn / Gln / Ser / Thr / Arg / Lys / His, Xaa 40 =Ile / Val / Leu, Xaa 41 =Ser / Thr / Ile / Val / Leu / Asp / Glu / deletion, Xaa 42 =Lys / Arg / His / Tyr / Phe / Trp / deletion, Xaa 43 =Ser / Thr / Tyr / Phe / Trp / deletion, Xaa 44 = Ser / Thr / Asn / Gln / Asp / Glu / deletion, Xaa 45 = Gly / Ala / deletion, Xaa 46 =Tyr / Phe / Trp / Asn / Gln / Lys / Arg / His / deletion, Xaa 47 =Lys / Arg / His / Ser / Thr / deletion, Xaa 48 = Asn / Gln / Tyr / Phe / Trp / deletion SEQ ID NO: 304 includes SEQ ID NO: 504 below. SEQ ID NO: 504: Xaa 737 -Xaa 738 -Xaa 739 -Xaa 740 -Xaa 741 -Xaa 742 -Xaa 743 Xaa 737 =Gln / Asn / Ser / Thr, Xaa 738 =Asn / Gln / Ser / Thr / Arg / Lys / His, Xaa 739 =Ile / Val / Leu, Xaa 740 = Ser / Thr / deletion, Xaa 741 =Tyr / Phe / Trp, Xaa 742 =Lys / Arg / His / deletion, Xaa 743 = Asn / Gln / deletion As SEQ ID NO:304, the following SEQ ID NOs:317, 318, 357 to 359 are preferred. SEQ ID NO: 317: Xaa158 -Xaa 159 -Xaa 160 -Xaa 161 -Xaa 162 -Xaa 163 Xaa 158 =Gln / Asn, Xaa 159 =Asn / Gln, Xaa 160 =Ile / Val / Leu, Xaa 161 =Tyr / Phe / Trp, Xaa 162 =Lys / Arg / His, Xaa 163 =Asn / Gln Sequence number 318: Xaa 164 -Xaa 165 -Xaa 166 -Xaa 167 -Xaa 168 Xaa 164 =Ser T h r, Xaa 165 =Ser / Thr / Arg / Lys / His, Xaa 166 =Ile / Val / Leu, Xaa 167 =Ser / Thr, Xaa 168 =Tyr / Phe / Trp Sequence number 357: Xaa 490 -Xaa 491 -Xaa 492 -Xaa 493 -Xaa 494 Xaa 490 =Ser / Thr, Xaa 491 =His / Arg / Lys, Xaa 492 =Ile / Val / Leu, Xaa 493 =Ser / Thr, Xaa 494 =Tyr / Phe / Trp Sequence number 358: Xaa 495 -Xaa 496 -Xaa 497 -Xaa 498 -Xaa 499 Xaa 495 =Ser / Thr, Xaa 496 =Ser / Thr, Xaa 497 =Ile / Val / Leu, Xaa498 =Ser / Thr, Xaa 499 =Tyr / Phe / Trp SEQ ID NO: 359: Xaa 500 -Xaa 501 -Xaa 502 -Xaa 503 -Xaa 504 -Xaa 505 Xaa 500 =Asn / Gln, Xaa 501 =Asn / Gln, Xaa 502 =Ile / Val / Leu, Xaa 503 =Asn / Gln, Xaa 504 =Asn / Gln, Xaa 505 =Tyr / Phe / Trp SEQ ID NO: 305: Xaa 49 -Xaa 50 -Xaa 51 Xaa 49 =Asn / Gln / Asp / Glu / Ile / Val / Leu / Thr / Ser / Tyr / Phe / Trp, Xaa 50 =Ala / Gly / Thr / Ser / Ile / Val / Leu / Pro / Cys / Met, Xaa 51 =Asn / Gln / Ser / Thr SEQ ID NO: 305 includes the following SEQ ID NO: 505. SEQ ID NO: 505: Xaa 744 -Xaa 745 -Xaa 746 Xaa 744 =Asn / Gln / Asp / Glu, Xaa 745 =Ala / Gly / Thr / Ser, Xaa 746 =Asn / Gln / Ser / Thr As SEQ ID NO:305, the following SEQ ID NOs:319, 320 and 360 are preferred. SEQ ID NO: 319: Xaa 169 -Xaa 170 -Xaa 171 Xaa 169 =Gln / Asn, Xaa 170= Ala / Gly, Xaa 171 = Gln / Asn Sequence number 320: Xaa 172 - Xaa 173 - Xaa 174 Xaa 172 = Asp / Glu, Xaa 173 = Thr / Ser, Xaa 174 = Ser / Thr Sequence number 360: Xaa 506 - Xaa 507 - Xaa 508 Xaa 506 = Tyr / Phe / Trp, Xaa 507 = Aly / Gly, Xaa 508 = Ser / Thr Sequence number 306: Xaa 52 - Xaa 53 - Xaa 54 - Xaa 55 - Xaa 56 - Xaa 57 - Xaa 58 - Xaa 59 - Xaa 60 - Xaa 61 Xaa 52 = Gln / Asn / Ile / Val / Leu / Tyr / Phe / Trp / deletion, Xaa 53 = Gln / Asn / Lys / Arg / His, Xaa 54 = Tyr / Phe / Trp / Ser / Thr / Gly / Ala / Lys / Arg / His, Xaa 55 = Tyr / Phe / Trp / Ser / Thr / Gln / Asn / Leu / Val / Ile / Lys / Arg / His / deletion, Xaa 56 = Ser / Thr / Lys / Arg / His / Asp / Glu / deletion, Xaa 57 = Gln / Asn / Ser / Thr / Gly / Ala / Tyr / Phe / Trp / Ile / Val / Leu / deletion, Xaa 58 = Thr / Ser / Pro / deletion, Xaa 59 = Gly / Ala / Pro / Gln / Asn / deletion, Xaa 60=Leu / Val / Ile / Tyr / Phe / Trp / deletion, Xaa 61 =Thr / Ser SEQ ID NO: 306 includes SEQ ID NO: 506 below. SEQ ID NO: 506: Xaa 747 -Xaa 748 -Xaa 749 -Xaa 750 -Xaa 751 -Xaa 752 -Xaa 753 -Xaa 754 -Xaa 755 -Xaa 756 Xaa 747 =Gln / Asn, Xaa 748 =Gln / Asn, Xaa 749 =Tyr / Phe / Trp, Xaa 750 = Tyr / Phe / Trp / deletion, Xaa 751 =Ser / Thr, Xaa 752 = Gln / Asn / Ser / Thr / deletion, Xaa 753 = Thr / Ser / deletion, Xaa 754 =Gly / Ala / Pro, Xaa 755 =Leu / Val / Ile / Tyr / Phe / Trp, Xaa 756 =Thr / Ser As SEQ ID NO:306, the following SEQ ID NOs:321, 322, 361 to 363 are preferred. SEQ ID NO: 321: Xaa 175 -Xaa 176 -Xaa 177 -Xaa 178 -Xaa 179 -Xaa 180 -Xaa 181 -Xaa 182 Xaa 175 =Gln / Asn, Xaa 176 =Gln / Asn, Xaa 177 =Tyr / Phe / Trp, Xaa 178 =Tyr / Phe / Trp, Xaa 179 =Ser / Thr, Xaa 180 =Gly / Ala / Pro, Xaa 181= Leu / Val / Ile, Xaa 182 = Thr / Ser Sequence No. 322: Xaa 183 - Xaa 184 - Xaa 185 - Xaa 186 - Xaa 187 - Xaa 188 - Xaa 189 - Xaa 190 - Xaa 191 Xaa 183 = Gln / Asn, Xaa 184 = Gln / Asn, Xaa 185 = Tyr / Phe / Trp, Xaa 186 = Ser / Thr, Xaa 187 = Gln / Asn / Ser / Thr, Xaa 188 = Thr / Ser, Xaa 189 = Gly / Ala / Pro, Xaa 190 = Tyr / Phe / Trp, Xaa 191 = Thr / Ser Sequence No. 361: Xaa 509 - Xaa 510 - Xaa 511 - Xaa 512 - Xaa 513 - Xaa 514 - Xaa 515 - Xaa 516 - Xaa 517 Xaa 509 = Gln / Asn, Xaa 510 = Gln / Asn, Xaa 511 = Tyr / Phe / Trp, Xaa 512 = Ser / Thr, Xaa 513 = Ser / Thr, Xaa 514 = Ser / Thr, Xaa 515 = Pro, Xaa 516 = Tyr / Phe / Trp, Xaa 517 = Ser / Thr Sequence No. 362: Xaa 518 - Xaa 519 - Xaa 520 - Xaa 521 - Xaa 522 - Xaa523 -Xaa 524 -Xaa 525 -Xaa 526 Xaa 518 =Gln / Asn, Xaa 519 =Gln / Asn, Xaa 520 =Tyr / Phe / Trp, Xaa 521 =Ser / Thr, Xaa 522 =Gln / Asn, Xaa 523 =Ser / Thr, Xaa 524 = Pro, Xaa 525 =Tyr / Phe / Trp, Xaa 526 = Ser / Thr SEQ ID NO: 363: Xaa 527 -Xaa 528 -Xaa 529 -Xaa 530 -Xaa 531 -Xaa 532 -Xaa 533 -Xaa 534 Xaa 527 =Gln / Asn, Xaa 528 =Gln / Asn, Xaa 529 =Tyr / Phe / Trp, Xaa 530 =Gln / Asn, Xaa 531 =Ser / Thr, Xaa 532 =Tyr / Phe / Trp, Xaa 533 =Leu / Val / Ile, Xaa 534 = Ser / Thr (2) Monoclonal antibody (II) Monoclonal antibody (II) comprises a heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 301, a heavy chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 302, and a heavy chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 307; and a light chain variable region comprising a light chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 308, a light chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 309, and a light chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 310; and binds to A1 beta-casein. SEQ ID NO: 307: Xaa 62 -Xaa63 -Xaa 64 -Xaa 65 -Xaa 66 -Xaa 67 -Xaa 68 -Xaa 69 -Xaa 70 -Xaa 71 -Xaa 72 -Xaa 73 -Xaa 74 -Xaa 75 -Xaa 76 -Xaa 77 -Xaa 78 Xaa 62 =Ala / Gly / Ser T hr / Val / Leu / Ile, Xaa 63 =Val / Leu / Ile / Gly / Ala / Lys / Arg / His / deletion, Xaa 64 =Tyr / Phe / Trp / Pro / Asp / Glu / Lys / Arg / His / deletion, Xaa 65 =Asp / Glu / Ala / Gly / Ser / Thr / Lys / Arg / His / Pro / deletion, Xaa 66 =Gly / Ala / Lys / Arg / His / Asp / Glu / Pro / Val / Leu / Ile / Tyr / Phe / Trp / deletion, Xaa 67 =Tyr / Phe / Trp / Lys / Arg / His / Ser / Thr / deletion, Xaa 68 =Tyr / Phe / Trp / Asn / Gln / Pro / Gly / Ala / Lys / Arg / His / deletion, Xaa 69 =Gly / Ala / Tyr / Phe / Trp / Asp / Glu / Ser / Thr / deletion, Xaa 70 =Asn / Gln / Ala / Gly / Ser / Thr / Phe / Tyr / Trp / Asp / Glu / Lys / Arg / His / deletion, Xaa 71 =Phe / Tyr / Trp / Ser / Thr / Val / Leu / Ile / Asp / Glu / Ala / Gly / deletion, Xaa 72 =Tyr / Phe / Trp / Asp / Glu / Lys / Arg / His / Ser / Thr / Gly / Ala / Pro, Xaa 73= Val / Leu / Ile / Asp / Glu / Ser T hr / Cys / Met / Lys / Arg / His / Gly / Ala / deletion, Xaa 74 = Tyr / Phe / Trp / Gly / Ala / Ser / Thr / deletion, Xaa 75 = Pro / Val / Leu / Ile / Gly / Ala / Phe / Tyr / Trp / deletion, Xaa 76 = Phe / Tyr / Trp / Met / Cys / Val / Leu / Ile / Lys / Arg / His / deletion, Xaa 77 = Asp / Glu / Gly / Ala / Pro / Val / Leu / Ile, Xaa 78 = Tyr / Phe / Trp SEQ ID NO: 307 includes the following SEQ ID NO: 507. SEQ ID NO: 507: Xaa 757 -Xaa 758 -Xaa 759 -Xaa 760 -Xaa 761 -Xaa 762 -Xaa 763 -Xaa 764 -Xaa 765 -Xaa 766 -Xaa 767 -Xaa 768 Xaa 757 = Ala / Gly, Xaa 758 = Val / Leu / Ile / Gly / Ala, Xaa 759 = Tyr / Phe / Trp, Xaa 760 = Asp / Glu / Ala / Gly, Xaa 761 = Gly / Ala / Lys / Arg / His, Xaa 762 = Tyr / Phe / Trp / Asp / Glu, Xaa 763 = Tyr / Phe / Trp, Xaa 764 = Pro / Val / Leu / Ile, Xaa 765 = Phe / Tyr / Trp / Met / Cys, Xaa 766 = Asp / Glu, Xaa 767 = Tyr / Phe / Trp, Xaa 768 = Phe / Tyr / Trp As SEQ ID NO: 307, the following SEQ ID NOs: 323, 324, 364 to 366 are preferred. SEQ ID NO: 323: Xaa 192 -Xaa 193 -Xaa 194 -Xaa 195 -Xaa 196 -Xaa 197 -Xaa 198 -Xaa 199 -Xaa 200 -Xaa 201 -Xaa 202 Xaa 192 = Ala / Gly, Xaa 193 = Val / Leu / Ile, Xaa 194 = Tyr / Phe / Trp, Xaa 195 = Asp / Glu, Xaa 196 = Gly / Ala, Xaa 197 = Tyr / Phe / Trp, Xaa 198 = Tyr / Phe / Trp, Xaa 199 = Pro / Val / Leu / Ile, Xaa 200 = Phe / Tyr / Trp, Xaa 201 = Asp / Glu, Xaa 202 = Tyr / Phe / Trp SEQ ID NO: 324: Xaa 203 -Xaa 204 -Xaa 205 -Xaa 206 -Xaa 207 -Xaa 208 -Xaa 209 -Xaa 210 -Xaa 211 -Xaa 212 -Xaa 213 Xaa 203 = Ala / Gly, Xaa 204 = Gly / Ala, Xaa 205 = Tyr / Phe / Trp, Xaa 206 = Ala / Gly, Xaa 207 = Lys / Arg / His, Xaa 208 = Asp / Glu, Xaa 209 = Tyr / Phe / Trp, Xaa 210=Pro / Val / Leu / Ile, Xaa 211 =Met / Cys, Xaa 212 =Asp / Glu, Xaa 213 =Tyr / Phe / Trp Sequence No. 364: Xaa 535 -Xaa 536 -Xaa 537 -Xaa 538 -Xaa 539 -Xaa 540 -Xaa 541 -Xaa 542 -Xaa 543 -Xaa 544 -Xaa 545 Xaa 535 =Gly / Ala, Xaa 536 =Lys / Arg / His, Xaa 537 =Gln / Asn, Xaa 538 =Tyr / Phe / Trp, Xaa 539 =Tyr / Phe / Trp, Xaa 540 =Gly / Ala, Xaa 541 =Val / Leu / Ile, Xaa 542 =Ser T hr, Xaa 543 =Gly / Ala, Xaa 544 =Asp / Glu, Xaa 545 =Tyr / Phe / Trp Sequence No. 365: Xaa 546 -Xaa 547 -Xaa 548 -Xaa 549 -Xaa 550 -Xaa 551 -Xaa 552 -Xaa 553 -Xaa 554 -Xaa 555 -Xaa 556 -Xaa 557 -Xaa 558 -Xaa 559 -Xaa 560 -Xaa 561 Xaa 546 =Gly / Ala, Xaa 547 =Lys / Arg / His, Xaa 548? 549 ? 550 The 551 __________________________ 552 ....... 553 __________________________ 554 I 555 The 556 ? 557 ____________________________ 558 __________________________ 559 __________________________ 560 ? 561 _________________________________ What is more? 562 ︁︁ 563 ︁︁ 564 ︁︁ 565 ︁︁ 566 ︁︁ 567 ︁︁ 568 ︁︁ 569 ︁︁ 570 ︁︁ 571 ︁︁ 572 ︁︁ 573 ︁︁ 574 ︁︁ 575 ︁︁ 576 ︁︁ 577 ︁︁ 578 ︁ 562 ? 563 ? 564 ? 565 ? 566 __________________________ 567 ? 568 __________________________ 569 ____________________________ 570 ....... 571 __________________________ 572 ?573 =Cys / Met, Xaa 574 =Gly / Ala, Xaa 575 =Tyr / Phe / Trp, Xaa 576 =Tyr / Phe / Trp, Xaa 577 =Gly / Ala, Xaa 578 =Tyr / Phe / Trp SEQ ID NO: 308: Xaa 79 -Xaa 80 -Xaa 81 -Xaa 82 -Xaa 83 -Xaa 84 -Xaa 85 -Xaa 86 -Xaa 87 -Xaa 88 -Xaa 89 -Xaa 90 Xaa 79 =Gln / Asn / Ser / Thr / Lys / Arg / His, Xaa 80 =Ser / Thr / Gly / Ala, Xaa 81 =Leu / Val / Ile, Xaa 82 =Leu / Val / Ile / Tyr / Phe / Trp / Ser / Thr / deletion, Xaa 83 = Asn / Gln / Arg / Lys / His / Ser / Thr / Asp / Glu / deletion, Xaa 84 =Ser / Thr / Leu / Val / Ile / deletion, Xaa 85 = Arg / Lys / His / Gly / Ala / Gln / Asn / Asp / Glu / deletion, Xaa 86 = Thr / Ser / Gly / Ala / deletion, Xaa 87 = Arg / Lys / His / Gln / Asn / deletion, Xaa 88 =Lys / Arg / His / Tyr / Phe / Trp / deletion, Xaa 89 = Asn / Gln / Ser / Thr / deletion, Xaa 90 =Tyr / Phe / Trp SEQ ID NO:308 includes the following SEQ ID NO:508. SEQ ID NO: 508: Xaa 768 -Xaa 769 -Xaa770 -Xaa 771 -Xaa 772 -Xaa 773 -Xaa 774 -Xaa 775 -Xaa 776 -Xaa 777 -Xaa 778 -Xaa 779 Xaa 768 =Gln / Asn, Xaa 769 =Ser T hr, Xaa 770 =Leu / Val / Ile, Xaa 771 =Leu / Val / Ile, Xaa 772 =Asn / Gln, Xaa 773 =Ser / T hr, Xaa 774 =Arg / Lys / His, Xaa 775 =T hr / Ser, Xaa 776 =Arg / Lys / His, Xaa 777 =Lys / Arg / His, Xaa 778 =Asn / Gln, Xaa 779 =Tyr / Phe / T rp As SEQ ID NO: 308, the following SEQ ID NOS: 367 to 371 are preferred. SEQ ID NO: 367: Xaa 579 -Xaa 580 -Xaa 581 -Xaa 582 -Xaa 583 -Xaa 584 -Xaa 585 -Xaa 586 -Xaa 587 -Xaa 588 -Xaa 589 -Xaa 590 Xaa 579 =Gln / Asn, Xaa 580 =Ser / T hr, Xaa 581 =Val / Leu / Ile, Xaa 582 =Val / Leu / Ile, Xaa 583 =Gln / Asn, Xaa 584 =Ser / T hr, Xaa 585 =Arg / Lys / His, Xaa 586= Ser / Thr, Xaa 587 = Arg / Lys / His, Xaa 588 = Arg / Lys / His, Xaa 589 = Gln / Asn, Xaa 590 = Tyr / Phe / Trp Sequence No. 368: Xaa 591 - Xaa 592 - Xaa 593 - Xaa 594 - Xaa 595 - Xaa 596 - Xaa 597 - Xaa 598 - Xaa 599 - Xaa 600 - Xaa 601 Xaa 591 = Gln / Asn, Xaa 592 = Gly / Ala, Xaa 593 = Val / Leu / Ile, Xaa 594 = Val / Leu / Ile, Xaa 595 = Arg / Lys / His, Xaa 596 = Ser / Thr, Xaa 597 = Gln / Asn, Xaa 598 = Gly / Ala, Xaa 599 = Gln / Asn, Xaa 600 = Ser / Thr, Xaa 601 = Tyr / Phe / Trp Sequence No. 369: Xaa 602 - Xaa 603 - Xaa 604 - Xaa 605 - Xaa 606 - Xaa 607 - Xaa 608 - Xaa 609 - Xaa 610 - Xaa 611 Xaa 602 = Arg / Lys / His, Xaa 603 = Ser / Thr, Xaa 604 = Val / Leu / Ile, Xaa 605 = Ser / Thr, Xaa 606 = Ser / Thr, Xaa 607 = Ser / Thr, Xaa608 = Gly / Ala, Xaa 609 = Tyr / Phe / Trp, Xaa 610 = Ser T h r, Xaa 611 = Tyr / Phe / Trp Sequence No. 370: Xaa 612 -Xaa 613 -Xaa 614 -Xaa 615 -Xaa 616 -Xaa 617 -Xaa 618 -Xaa 619 -Xaa 620 -Xaa 621 -Xaa 622 Xaa 612 = Asn / Gln, Xaa 613 = Ser / Thr, Xaa 614 = Val / Leu / Ile, Xaa 615 = Val / Leu / Ile, Xaa 616 = Arg / Lys / His, Xaa 617 = Ser / Thr, Xaa 618 = Asn / Gln, Xaa 619 = Gly / Ala, Xaa 620 = Asn / Gln, Xaa 621 = Ser / Thr, Xaa 622 = Tyr / Phe / Trp Sequence No. 371: Xaa 623 -Xaa 624 -Xaa 625 -Xaa 626 -Xaa 627 -Xaa 628 -Xaa 629 -Xaa 630 -Xaa 631 -Xaa 632 -Xaa 633 Xaa 623 = Asn / Gln, Xaa 624 = Gly / Ala, Xaa 625 = Val / Leu / Ile, Xaa 626 = Val / Leu / Ile, Xaa 627 = Arg / Lys / His, Xaa 628=Ser / Thr, Xaa 629 =Asn / Gln, Xaa 630 =Gly / Ala, Xaa 631 =Asn / Gln, Xaa 632 =Ser / Thr, Xaa 633 =Tyr / Phe / Trp SEQ ID NO: 309: Xaa 91 -Xaa 92 -Xaa 93 Xaa 91 =Trp / Phe / Tyr / Lys / Arg / His / Gly / Ala / Leu / Val / Ile, Xaa 92 =Ala / Gly / Leu / Val / Ile / Ser / Thr, Xaa 93 = Ser / Thr SEQ ID NO: 309 includes the following SEQ ID NO: 509. SEQ ID NO: 509: Xaa 780 -Xaa 781 -Xaa 782 Xaa 780 =Trp / Phe / Tyr, Xaa 781 =Ala / Gly, Xaa 782 = Ser / Thr As SEQ ID NO:309, the following SEQ ID NOs:372 to 374 are preferred. SEQ ID NO: 372: Xaa 634 -Xaa 635 -Xaa 636 Xaa 634 =Tyr / Phe / Trp, Xaa 635 =Ala / Gly, Xaa 636 = Ser / Thr SEQ ID NO: 373: Xaa 637 -Xaa 638 -Xaa 639 Xaa 637 =Arg / Lys / His, Xaa 638 =Val / Leu / Ile, Xaa 639 = Ser / Thr SEQ ID NO: 374: Xaa 640 -Xaa 641-Xaa 642 Xaa 640 =Leu / Val / Ile, Xaa 641 =Val / Leu / Ile, Xaa 642 =Ser T h r Sequence No. 310: Xaa 94 -Xaa 95 -Xaa 96 -Xaa 97 -Xaa 98 -Xaa 99 -Xaa 100 -Xaa 101 -Xaa 102 Xaa 94 =Gln / Asn / Lys / Arg / His / Tyr / Phe / Trp / Ser / Thr, Xaa 95 =Gln / Asn / Lys / Arg / His, Xaa 96 =Ser / Thr / Asp / Glu / Ala / Gly / Tyr / Phe / Trp / Val / Leu / Ile, Xaa 97 =Tyr / Phe / Trp / Ser / Thr / Ala / Gly / deletion, Xaa 98 =Asn / Gln / Thr / Ser / Lys / Arg / His / Leu / Val / Ile, Xaa 99 =Leu / Val / Ile / Tyr / Phe / Trp / Lys / Arg / His / Asp / Glu, Xaa 100 =Pro / Val / Leu / Ile, Xaa 101 =Trp / Phe / Tyr / Thr / Ser / deletion, Xaa 102 =Thr / Ser / Lys / Arg / His Examples of Sequence No. 310 include the following Sequence No. 510. Sequence No. 510: Xaa 783 -Xaa 784 -Xaa 785 -Xaa 786 -Xaa 787 -Xaa 788 -Xaa 789 -Xaa 790 -Xaa 791 Xaa 783= Gln / Asn / Lys / Arg / His, Xaa 784 = Gln / Asn, Xaa 785 = Ser T h r, Xaa 786 = Tyr / Phe / Trp, Xaa 787 = Asn / Gln / Thr / Ser, Xaa 788 = Leu / Val / Ile, Xaa 789 = Pro / Val / Leu / Ile, Xaa 790 = Trp / Phe / Tyr, Xaa 791 = Thr / Ser SEQ ID NO: 310 preferably includes the following SEQ ID NOs: 325, 326, 375, and 376. SEQ ID NO: 325: Xaa 214 - Xaa 215 - Xaa 216 - Xaa 217 - Xaa 218 - Xaa 219 - Xaa 220 - Xaa 221 - Xaa 222 Xaa 214 = Gln / Asn, Xaa 215 = Gln / Asn, Xaa 216 = Ser / Thr, Xaa 217 = Tyr / Phe / Trp, Xaa 218 = Asn / Gln, Xaa 219 = Leu / Val / Ile, Xaa 220 = Pro / Val / Leu / Ile, Xaa 221 = Trp / Phe / Tyr, Xaa 222 = Thr / Ser SEQ ID NO: 326: Xaa 223 - Xaa 224 - Xaa 225 - Xaa 226 - Xaa 227 - Xaa 228 - Xaa 229 - Xaa 230 - Xaa 231 Xaa 223 = Lys / Arg / His, Xaa 224 = Gln / Asn, Xaa 225= Ser / Thr, Xaa 226 = Tyr / Phe / Trp, Xaa 227 = Thr / Ser, Xaa 228 = Leu / Val / Ile, Xaa 229 = Pro / Val / Leu / Ile, Xaa 230 = Trp / Phe / Tyr, Xaa 231 = Thr / Ser Sequence No. 375: Xaa 643 -Xaa 644 -Xaa 645 -Xaa 646 -Xaa 647 -Xaa 648 -Xaa 649 -Xaa 650 -Xaa 651 Xaa 643 = Ser / Thr / His, Xaa 644 = Asn / Gln, Xaa 645 = Ser / Thr, Xaa 646 = Ser / Thr, Xaa 647 = Lys / Arg / His, Xaa 648 = Val / Leu / Ile, Xaa 649 = Pro, Xaa 650 = Tyr / Phe / Trp, Xaa 651 = Ser / Thr Sequence No. 376: Xaa 652 -Xaa 653 -Xaa 654 -Xaa 655 -Xaa 656 -Xaa 657 -Xaa 658 -Xaa 659 Xaa 652 = Asn / Gln, Xaa 653 = Lys / Arg / His, Xaa 654 = Val / Leu / Ile, Xaa 655 = Lys / Arg / His, Xaa 656 = Asp / Glu, Xaa 657 = Val / Leu / Ile, Xaa 658 = Ser / Thr, Xaa 659 = Lys / Arg / His (3) Monoclonal antibody (III) The monoclonal antibody (III) comprises a heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 301, a heavy chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 302, and a heavy chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 311; and a light chain variable region comprising a light chain complementarity determining region 1 comprising the amino acid sequence of SEQ ID NO: 312, a light chain complementarity determining region 2 comprising the amino acid sequence of SEQ ID NO: 313, and a light chain complementarity determining region 3 comprising the amino acid sequence of SEQ ID NO: 314; and binds to A1 beta-casein and A2 beta-casein. SEQ ID NO: 311: Xaa 102 -Xaa 103 -Xaa 104 -Xaa 105 -Xaa 106 -Xaa 107 -Xaa 108 -Xaa 109 -Xaa 110 -Xaa 111 -Xaa 112 -Xaa 113 -Xaa 114 Xaa 102 =Val / Leu / Ile / Ala / Gly / Ser / Thr, Xaa 103 =Arg / Lys / His / Ser / Thr, Xaa 104 =His / Lys / Arg / Gly / Ala / Val / Leu / Ile / deletion, Xaa 105 = Gly / Ala / Ser / Thr / deletion, Xaa 106 =Arg / His / Lys / Gly / Ala / deletion, Xaa 107 =Arg / His / Lys / Ser / Thr / Phe / Tyr / Trp / Gly / Ala / deletion, Xaa 108 = Gln / Asn / Pro / deletion, Xaa 109 =Phe / Tyr / Trp / Val / Leu / Ile / deletion, Xaa 110 =Asp / Glu / Pro / Ala / Gly / Gln / Asn / Gly / Ala / Phe / Tyr / Trp / deletion, Xaa 111 = Ser / Thr / deletion, Xaa 112=Phe / Tyr / Trp / Ser / Thr / deletion, Xaa 113 =Arg / His / Lys / Phe / Tyr / Trp / Asp / Glu / deletion, Xaa 114 =Val / Leu / Ile / Phe / Tyr / Trp / deletion SEQ ID NO:311 includes the following SEQ ID NO:511. SEQ ID NO: 511: Xaa 792 -Xaa 793 -Xaa 794 -Xaa 795 -Xaa 796 -Xaa 797 -Xaa 798 -Xaa 799 -Xaa 800 -Xaa 801 Xaa 792 =Val / Leu / Ile / Ala / Gly, Xaa 793 =Arg / Lys / His, Xaa 794 =His / Lys / Arg, Xaa 795 = Gly / Ala / deletion, Xaa 796 =Arg / His / Lys, Xaa 797 =Arg / His / Lys / Ser / Thr, Xaa 798 = Gln / Asn / deletion, Xaa 799 =Phe / Tyr / Trp, Xaa 800 =Asp / Glu / Pro / Ala / Gly, Xaa 801 =Phe / Tyr / Trp As SEQ ID NO:311, the following SEQ ID NOs:327 to 329 and 377 are preferred. SEQ ID NO: 327: Xaa 232 -Xaa 233 -Xaa 234 -Xaa 235 -Xaa 236 -Xaa 237 -Xaa 238 -Xaa 239 -Xaa 240 Xaa 232 =Val / Leu / Ile, Xaa 233 =Arg / Lys / His, Xaa 234= His / Lys / Arg, Xaa 235 = Gly / Ala, Xaa 236 = Arg / His / Lys, Xaa 237 = Arg / His / Lys, Xaa 238 = Phe / Tyr / Trp, Xaa 239 = Asp / Glu, Xaa 240 = Phe / Tyr / Trp Sequence number 328: Xaa 241 -Xaa 242 -Xaa 243 -Xaa 244 -Xaa 245 -Xaa 246 -Xaa 247 -Xaa 248 Xaa 241 = Ala / Gly, Xaa 242 = Arg / Lys / His, Xaa 243 = His / Lys / Arg, Xaa 244 = Arg / His / Lys, Xaa 245 = Ser T hr, Xaa 246 = Phe / Tyr / Trp, Xaa 247 = Pro / Ala / Gly, Xaa 248 = Phe / Tyr / Trp Sequence number 329: Xaa 249 -Xaa 250 -Xaa 251 -Xaa 252 -Xaa 253 -Xaa 254 -Xaa 255 -Xaa 256 -Xaa 257 -Xaa 258 Xaa 249 = Ala / Gly, Xaa 250 = Arg / Lys / His, Xaa 251 = His / Lys / Arg, Xaa 252 = Gly / Ala, Xaa 253 = Arg / His / Lys, Xaa 254 = Ser / T hr, Xaa 255 = Gln / Asn, Xaa 256 = Phe / Tyr / Trp, Xaa257 = Ala / Gly, Xaa 258 = Phe / Tyr / Trp Sequence No. 377: Xaa 660 -Xaa 661 -Xaa 662 -Xaa 663 -Xaa 664 -Xaa 665 -Xaa 666 -Xaa 667 -Xaa 668 -Xaa 669 -Xaa 670 -Xaa 671 -Xaa 672 Xaa 660 = Ser T h r, Xaa 661 = Arg / Lys / His, Xaa 662 = Val / Leu / Ile, Xaa 663 = Ala / Gly, Xaa 664 = Ala / Gly, Xaa 665 = Ala / Gly, Xaa 666 = Pro, Xaa 667 = Phe / Tyr / Trp, Xaa 668 = Phe / Tyr / Trp, Xaa 669 = Ser / Thr, Xaa 670 = Phe / Tyr / Trp, Xaa 671 = Glu / Asp, Xaa 672 = Phe / Tyr / Trp Sequence No. 312: Xaa 115 -Xaa 116 -Xaa 117 -Xaa 118 -Xaa 119 -Xaa 120 -Xaa 121 -Xaa 122 -Xaa 123 -Xaa 124 -Xaa 125 -Xaa 126 Xaa 115 = Gln / Asn, Xaa 116 = Asn / Gln / Asp / Glu / Ser / Thr / Deletion, Xaa 117 = Ser / Thr / Ile / Val / Leu / Deletion, Xaa118 =Ile / Val / Leu / deletion, Xaa 119 =Val / Leu / Ile / Gly / Ala / Tyr / Phe / Trp / Asp / Glu / deletion, Xaa 120 =His / Lys / Arg / Ser / Thr / Asn / Gln / deletion, Xaa 121 = Ser / Thr / deletion, Xaa 122 = Asp / Glu / Gly / Ala / deletion, Xaa 123 =Gly / Ala / His / Lys / Arg / deletion, Xaa 124 = Asn / Gln / Asp / Glu / Lys / Arg / His / deletion, Xaa 125 =Lys / Arg / His / Thr / Ser / deletion, Xaa 126 =Tyr / Phe / Trp SEQ ID NO:312 includes the following SEQ ID NO:512. SEQ ID NO: 512: Xaa 802 -Xaa 803 -Xaa 804 -Xaa 805 -Xaa 806 -Xaa 807 -Xaa 808 -Xaa 809 -Xaa 810 -Xaa 811 -Xaa 812 -Xaa 813 Xaa 802 =Gln / Asn, Xaa 803 = Asn / Gln / deletion, Xaa 804 = Ser / Thr / deletion, Xaa 805 =Ile / Val / Leu, Xaa 806 =Val / Leu / Ile / deletion, Xaa 807 =His / Lys / Arg / deletion, Xaa 808 = Ser / Thr / deletion, Xaa 809 = Asp / Glu / deletion, Xaa 810 = Gly / Ala / deletion, Xaa 811 =Asn / Gln, Xaa 812 =Lys / Arg / His / Thr / Ser, Xaa 813 =Tyr / Phe / Trp As SEQ ID NO: 312, the following SEQ ID NOs: 330, 331 and 378 are preferred. SEQ ID NO: 330: Xaa 258 -Xaa 259 -Xaa 260 -Xaa 261 -Xaa 262 -Xaa 263 Xaa 258 =Gln / Asn, Xaa 259 =Asn / Gln, Xaa 260 =Ile / Val / Leu, Xaa 261 =Asn / Gln, Xaa 262 =Lys / Arg / His, Xaa 263 =Tyr / Phe / Trp SEQ ID NO: 331: Xaa 264 -Xaa 265 -Xaa 266 -Xaa 267 -Xaa 268 -Xaa 269 -Xaa 270 -Xaa 271 -Xaa 272 -Xaa 273 -Xaa 274 Xaa 264 =Gln / Asn, Xaa 265 =Ser T hr, Xaa 266 =Ile / Val / Leu, Xaa 267 =Val / Leu / Ile, Xaa 268 =His / Lys / Arg, Xaa 269 =Ser / T hr, Xaa 270 =Asp / Glu, Xaa 271 =Gly / Ala, Xaa 272 =Asn / Gln, Xaa 273 =Thr / Ser, Xaa 274 =Tyr / Phe / Trp SEQ ID NO: 378: Xaa 673 -Xaa 674 -Xaa 675 -Xaa 676 -Xaa 677 -Xaa 678 Xaa673 =Gln / Asn, Xaa 674 =Glu / Asp, Xaa 675 =Val / Leu / Ile, Xaa 676 =Ala / Gly, Xaa 677 =Gln / Asn, Xaa 678 =Phe / Tyr / Trp SEQ ID NO: 313: Xaa 127 -Xaa 128 -Xaa 129 Xaa 127 =Asn / Gln / Arg / Lys / His / Gly / Ala / Val / Leu / Ile, Xaa 128 =Thr / Ser / Val / Leu / Ile / His / Lys / Arg / Gly / Ala, Xaa 129 =Asn / Gln / Ser / Thr SEQ ID NO: 313 includes the following SEQ ID NO: 513. SEQ ID NO: 513: Xaa 814 -Xaa 815 -Xaa 816 Xaa 814 =Asn / Gln / Arg / Lys / His, Xaa 815 =Thr / Ser / Val / Leu / Ile, Xaa 816 =Asn / Gln / Ser / Thr As SEQ ID NO:313, the following SEQ ID NOs:332, 333 and 379 are preferred. SEQ ID NO: 332: Xaa 275 -Xaa 276 -Xaa 277 Xaa 275 =Asn / Gln, Xaa 276 =Thr / Ser, Xaa 277 = Asn / Gln SEQ ID NO: 333: Xaa 278 -Xaa 279 -Xaa 280 Xaa 278 =Arg / Lys / His, Xaa 279 =Val / Leu / Ile, Xaa 280= Ser / Thr SEQ ID NO: 379: Xaa 679 - Xaa 680 - Xaa 681 Xaa 679 = Ala / Gly, Xaa 680 = Ala / Gly, Xaa 681 = Ser / Thr SEQ ID NO: 314: Xaa 130 - Xaa 131 - Xaa 132 - Xaa 133 - Xaa 134 - Xaa 135 - Xaa 136 - Xaa 137 - Xaa 138 Xaa 130 = Cys / Met / Phe / Tyr / Trp / Leu / Val / Ile, Xaa 131 = Gln / Asn, Xaa 132 = His / Lys / Arg / Ser / Thr / Ala / Gly, Xaa 133 = Asn / Gln / Ala / Gly / Asp / Glu / His / Lys / Arg / Ser / Thr, Xaa 134 = Ser / Thr / His / Lys / Arg / Asn / Gln, Xaa 135 = Trp / Phe / Tyr / Ala / Gly, Xaa 136 = Pro / Val / Leu / Ile, Xaa 137 = Val / Leu / Ile / Pro / Asp / Glu / Trp / Phe / Tyr, Xaa 138 = Thr / Ser SEQ ID NO: 314 includes the following SEQ ID NO: 514. SEQ ID NO: 514: Xaa 817 - Xaa 818 - Xaa 819 - Xaa 820 - Xaa 821 - Xaa 822 - Xaa 823 - Xaa 824 - Xaa 825 Xaa 817[y] / !!4\\ / / / / / / / / / + / !! / ️️!!! 818 ....... 819 [His / ys / ｡ｽo / ｽro / ]ｽｽ!! 820 The 821 I 822 __________________________ 823 I 824 The 825 ________________ 2013-05-20 10:00:00:0000:0000:00000000000000:000:00:00:00 Beautiful What is more? 281 ︁︁ 282 ︁︁ 283 ︁︁ 284 ︁︁ 285 ︁︁ 286 ︁︁ 287 ︁︁ 288 ︁︁ 289 ︁ 281 [y] / !tt / / / / / !!!!verage 282 ....... 283 I 284 The 285 ____________________________ 286 __________________________ 287 I 288 The 289 ________________ What is more? 290 ︁︁ 291 ︁︁ 292 ︁︁ 293 ︁︁ 294 ︁︁ 295 ︁︁ 296 ︁︁ 297 ︁︁ 298 ︁ 290 I291 = Gln / Asn, Xaa 292 = Ser T h r, Xaa 293 = Ala / Gly, Xaa 294 = His / Lys / Arg, Xaa 295 = Trp / Phe / Tyr, Xaa 296 = Pro / Val / Leu / Ile, Xaa 297 = Val / Leu / Ile, Xaa 298 = Thr / Ser Sequence No. 380: Xaa 682 - Xaa 683 - Xaa 684 - Xaa 685 - Xaa 686 - Xaa 687 - Xaa 688 - Xaa 689 - Xaa 690 Xaa 682 = Val / Leu / Ile, Xaa 683 = Gln / Asn, Xaa 684 = His / Lys / Arg, Xaa 685 = His / Lys / Arg, Xaa 686 = Gln / Asn, Xaa 687 = Trp / Phe / Tyr, Xaa 688 = Pro, Xaa 689 = Pro, Xaa 690 = Thr / Ser An "antibody" is a glycoprotein produced by lymphocyte B cells, and has the function of recognizing and binding to specific proteins and other molecules. Antibodies have the function of specifically binding to specific molecules called antigens, and the function of detoxifying and removing factors that have antigens in cooperation with other biological molecules and cells. Antibodies basically have the same molecular structure, and have a four-chain "Y" shape consisting of two light chains and two heavy chain polypeptides. There are two types of light chains (L chains), λ chains and κ chains, and all antibodies have one of these. There are five types of heavy chains (H chains), which have different structures: γ chains, μ chains, α chains, δ chains, and ε chains, and the type of antibody (isotype) changes depending on the difference in the heavy chain. Antibodies are monomeric immunoglobulins, consisting of two heavy chains (γ chains) and two light chains, and have two antigen-binding sites. The lower half of the "Y" of an antibody is called the Fc region, and the upper half of the "V" is called the Fab region. The Fc region has an effector function that triggers a reaction after the antibody binds to an antigen, and the Fab region has the function of binding to the antigen. The Fab region and Fc region of the heavy chain are connected by a hinge, and the proteolytic enzyme papain contained in papaya degrades this hinge and cleaves it into two Fab regions and one Fc region. The domain of the Fab region near the tip of the "Y" is called the variable region (V region) because the amino acid sequence shows various changes so that it can bind to various antigens. The variable region of the light chain is called the VL region, and the variable region of the heavy chain is called the VH region. The Fab region and Fc region other than the V region are relatively unchanged and are called the constant region (C region). The light chain constant region is called the CL region, and the heavy chain constant region is called the CH region, which is further divided into three regions, CH1 to CH3. The heavy chain Fab region consists of the VH region and CH1, and the heavy chain Fc region consists of CH2 and CH3. The hinge region is located between CH1 and CH2. Each of the heavy chain and the light chain includes a variable region consisting of about 100 or more amino acids, for example, 130 to 140 amino acids, which are mainly involved in antigen binding. The variable region of the heavy chain is also referred to as the heavy chain variable region (VH). The variable region of the light chain is also referred to as the light chain variable region (VL). Each variable region includes a complementarity determining region (CDR) that forms an antigen binding site. Each of the VH and VL includes three CDRs. That is, the VH includes a first CDR (HCDR1), a second CDR (HCDR2), and a third CDR (HCDR3). The VL includes a first CDR (LCDR1), a second CDR (LCDR2), and a third CDR (LCDR3). The regions other than the CDRs of the heavy chain and the light chain have amino acid sequences according to the animal species and isotype, but are not limited thereto. The monoclonal antibody according to the present invention can be produced by a conventional method. For example, first, an animal is immunized with an antigen. When producing an anti-A1 beta casein antibody specific to A1 beta casein, an antigen containing histidine at position 67 of A1 beta casein is used. When producing an anti-A1 / A2 beta casein antibody that binds to both A1 beta casein and A2 beta casein, an antigen that does not contain the amino acid residue at position 67 and contains an amino acid sequence common to both A1 beta casein and A2 beta casein is used. The number of amino acid residues contained in the antigen can be adjusted to, for example, 10 or more and 20 or less. For example, mice, rats, guinea pigs, rabbits, goats, sheep, donkeys, chickens, etc. can be used as experimental animals. For example, an injection containing the antigen may be administered to the tail or intraperitoneally. Next, B cells are extracted from the spleen or lymph nodes of the immunized animal and fused with myeloma cells to produce hybridomas. Among the produced hybridomas, hybridomas that produce antibodies with excellent specific binding ability to the antigen are screened using a plate on which the antigen is immobilized, and are then grown. The desired antibody can be purified from the culture solution of the obtained hybridomas. The binding activity of the monoclonal antibody according to the present invention to A1 beta-casein, or to A1 beta-casein and A2 beta-casein, may be evaluated separately by surface plasmon resonance, biolayer interference, or the like. The monoclonal antibody according to the present invention can specifically bind to A1 beta casein, or A1 beta casein and A2 beta casein, and can be used to detect A1 beta casein in particular. Specifically, a milk sample is mixed with the anti-A1 beta casein antibody according to the present invention, and A1 beta casein contained in the milk sample is selectively bound to the antibody, thereby detecting the A1 beta casein. In the present disclosure, "detection" also includes "quantification," and it is possible to quantify the amount of A1 beta-casein contained in a milk sample by preparing a calibration curve in advance using a milk sample with a known amount and concentration of A1 beta-casein and the monoclonal antibody of the present invention. Below, the method for detecting A1 beta-casein according to the present invention will be explained step by step, but the present invention is not limited to the following specific examples. 1. Sample pretreatment process In this step, the milk sample in which A1 beta casein is to be detected is pretreated to improve the detection sensitivity. This step is optional, and for example, when the milk sample is directly subjected to measurement, this step does not need to be performed. Examples of pretreatment include dilution, defatting, and sterilization of the milk sample. The dilution ratio may be determined within a range in which the concentration of A1 beta casein can be determined from the measured value of ELISA using a calibration curve, and may be, for example, 1000 times or more and 100,000 times or less. PBS or the like may be used for dilution. Defatting may be performed according to a conventional method. Sterilization may be performed by either high-temperature sterilization or low-temperature sterilization. 2. ELISA process In this step, A1 beta-casein contained in the milk sample is detected by ELISA (Enzyme-Linked Immuno Sorbent Assay). As ELISA, direct method, indirect method, sandwich method, etc. are mainly known, but from the viewpoint of high accuracy, sandwich ELISA will be explained below. (1) Immobilization step of capture antibody In this step, the capture antibody is immobilized on a plate or the like. Plates for immobilizing antibodies are commercially available. Specifically, a capture antibody solution is added to each well of a microtiter plate made of polyvinyl chloride, polystyrene, or the like, and incubated, followed by washing. The capture antibody may be an anti-A1 beta casein antibody or an anti-A1 / A2 beta casein antibody. According to the experimental findings of the present inventors, whether the capture antibody is an anti-A1 beta casein antibody or an anti-A1 / A2 beta casein antibody, A1 beta casein can be detected well. (2) Mixing process of milk samples Next, the pretreated milk sample is added to the plate with the capture antibody immobilized on the surface. As a result, A1 beta casein or A1 beta casein and A2 beta casein contained in the milk sample specifically bind to the antibody of the present invention. Then, the plate is washed. (3) Detection step Next, a detection antibody, which is an anti-A1 beta casein antibody, is added to the plate after adding the milk sample, and the detection antibody is quantified by an enzyme reaction. The epitope of the detection antibody is different from the epitope of the capture antibody. The capture antibody may be an enzyme-labeled one, or, in addition to the detection antibody, a secondary antibody that specifically binds to the detection antibody and is enzyme-labeled may be used. The detection antibody may be quantified by a method according to the labeling enzyme bound to the detection antibody or the secondary antibody. For example, when the labeling enzyme is horseradish peroxidase (HRP), hydrogen peroxide and a coloring agent are added. Examples of coloring agents used in combination with HRP include 3,3',5,5'-tetramethylbenzidine (TMB), o-phenylenediamine dihydrochloride (OPD), and 2,2'-azino-di-[3-ethyl-benzothiazoline-6 ​​sulfonic acid] diammonium salt (ABTS), and the absorbance at a wavelength according to the coloring agent may be measured. When the labeling enzyme is alkaline phosphatase (ALP), for example, nitrophenyl phosphate (pNPP) may be used as a coloring agent, and the absorbance at 405 nm may be measured. As mentioned above, if a calibration curve is created using a milk sample in which the amount and proportion of A1 beta-casein is known, it is also possible to quantify the A1 beta-casein contained in the milk sample. In addition, the proportion of A1 beta casein in beta casein in A2 milk, which is considered to have a low proportion of A1 beta casein and no harmful effects of A1 beta casein, is said to be 30% by mass or less. According to the experimental findings of the present inventors, the monoclonal antibody of the present invention can detect 2% by mass or more of A1 beta casein relative to the total beta casein, so the detection method of A1 beta casein of the present invention is very excellent as a method for evaluating milk. However, the higher the proportion of A1 beta casein relative to the total beta casein, the easier it is to detect A1 beta casein, and the proportion is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more or 30% by mass or more. This application claims the benefit of priority based on Japanese Patent Application No. 2022-158177, filed on September 30, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-158177, filed on September 30, 2022, are incorporated by reference into this application. The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and it is of course possible to carry out the present invention with appropriate modifications within the scope of the above and below-mentioned aims, and all of these modifications are included in the technical scope of the present invention. Example 1: Preparation of monoclonal antibodies by lymph node assay (1) Preparation of antigen / adjuvant emulsion Two 1 mL Luer-lock glass syringes were placed on either end of the locking needle connector. The plunger was removed from the top syringe before connection. Complete Freund's adjuvant (750 μL) was mixed well and added to the top syringe with the plunger removed using a pipette for non-aqueous liquids. The plunger of the bottom syringe was pulled back to fill the interior with adjuvant, and then the plunger was replaced, returning the adjuvant to the top syringe. The antigen protein shown in Table 1 was dissolved in PBS to prepare a 0.5 mg / mL solution for mice and a 1 mg / mL solution for rats. Each solution (350 μL) was placed in the upper syringe, and the plunger of the lower syringe was pulled to aspirate the antigen and adjuvant into the lower syringe. The upper syringe was removed and the plunger was returned to its original position. The plunger of the lower syringe was slowly pushed up to expel air bubbles. The top syringe was connected, the syringe was held horizontally, and the plunger was moved back and forth quickly approximately 10 times to emulsify the mixture. The resulting emulsion was drawn into one syringe, and the other syringe and needle connector were removed and a disposable needle was attached. (2) Intramuscular injection into the base of the tail Mice or rats were anesthetized with sevoflurane and anesthesia was confirmed by lack of response to stimuli. 50 μL of antigen-adjuvant emulsion was injected intramuscularly for mice and 100 μL for rats into the right side of the base of the tail. The needle was removed and a 5 second wait was then performed on the left side. The injected mice or rats were placed in a cage at 37° C. until awake and then returned to normal housing. (3) Collection of iliac lymph nodes Approximately 14-21 days after injection, enlarged iliac lymph nodes were harvested if the injection was successful. 8 , and 0.5-2.0 × 10 from three rats. 8 In the case of the electric cell fusion method, it is expected that 0.5 × 10 B cells can be collected. 8 More than one cell is required. Specifically, immunized mice or rats were euthanized and the ventral skin was sprayed with 70% ethanol, the ventral skin and muscle were opened, the intestines were avoided, and the enlarged iliac lymph nodes were located and harvested, transferred to Dulbecco's Modified Eagle Medium (DMEM), and moved under a tissue culture hood. (4) Isolation of B cells The harvested lymph nodes were transferred to a steel wire mesh in a 60 mm culture dish and DMEM (10 mL) was added. The lymph nodes were triturated with a spatula through the wire mesh. Cells (mainly B cells) were collected in a 50 mL tube using a pipette. The supernatant was removed from the cell pellet after centrifugation at 1500 rpm and 500 G for 5 minutes. The cells were resuspended in DMEM (10 mL). The centrifugation and resuspension procedure was repeated. (5) Cell fusion Two days prior to fusion, SP2 / 0-Ag14 myeloma cells were split into DMEM using fresh culture medium to induce cells into logarithmic growth phase. The supernatant was removed from the cell pellet after centrifugation at 1500 rpm for 5 minutes. The cells were resuspended in DMEM (10 mL). The centrifugation and resuspension procedure was repeated. The number of myeloma cells was counted using a cell counting chamber and 2.0 x 10 cells were transferred to a new 50 mL tube. 7 A cell suspension was prepared. Also, count the number of B cells using a cell counting chamber and place 5.0 x 10 cells in a new 50 mL tube. 7 A cell suspension was prepared and incubated at room temperature for 5 minutes. The B cell suspension and the myeloma cell suspension were mixed and centrifuged at 1500 rpm for 5 minutes, the supernatant was removed from the cell pellet, and the cells were resuspended in ECF buffer (10 mL). The centrifugation and resuspension procedure was repeated. Both cell suspensions were centrifuged at 1500 rpm for 5 minutes, the supernatant was removed from the cell pellet, and the cells were resuspended in ECF buffer (1 mL). The suspensions of both cells (500 μL) were placed in the electrode chamber, and the chamber was placed in a cell fusion device ("Super Cell Fusion Device ECFG21" manufactured by Nepa Gene Co., Ltd.). The impedance was measured using an electric cell fusion generator, a DC pulse voltage was set, and a rectangular pulse was applied. The fusion procedure was repeated for the remaining cell suspension. The fused cell suspension was collected in a 50 mL tube containing HAT medium (40 mL). The fused cell suspension (100 μL) was seeded into a 96-well plate using a multichannel pipette and incubated at 37° C. in a CO 2 incubator. (6) Hybridoma culture and cryopreservation Five days after cell fusion, the medium was carefully removed using an 8-channel aspirator, and HAT medium (200 μL) was added to each well of the plate. Eight days after cell fusion, the supernatant (100 μL) was used to confirm by ELISA which wells were positive for A1 beta-casein and negative for A2 beta-casein, or which were positive for A1 beta-casein and positive for A2 beta-casein. One day after confirmation by ELISA, the cells in the wells were transferred to a 24-well plate containing HT medium (1 mL). After 2 to 3 days, the culture supernatant was collected from each well into a new 1.5 mL tube and stored at 4°C or -30°C. Fresh medium (250 μL) was added, and the cells were suspended by pipetting. Storage medium (250 μL) was added, mixed well, transferred to a freezing tube, and stored at −80° C. (7) Hybridoma cloning Frozen cell stocks of hybridomas were removed from a -80°C freezer and rapidly thawed at 37°C. Once the cells were almost completely thawed, the vial containing the cells was placed in a tissue culture hood. After replacing the contents of the vial with HT medium, the number of viable hybridomas was counted using a cell counter and 2.0 x 10 cells were counted in HT medium (20 mL) in a 50 mL tube. 2 A suspension containing dispersed cells was prepared. The resulting hybridoma suspension (100 μL) was seeded into two 96-well plates and incubated at 37° C. under CO2. Five days after seeding, HT medium (100 μL) was added, and 8 days later, positive wells were confirmed by ELISA. One day after ELISA, the positive hybridomas were transferred to a 24-well plate and subcultured for 2 to 3 days, and then storage medium (250 μL) was added and mixed well, transferred to a cryotube, and stored at −80° C. To obtain a large amount of monoclonal antibodies, the hybridomas of the positive clones were thawed and cultured, and then transferred to a 75 cm 2 The cells were allowed to grow until they reached the number of plates corresponding to 3 to 4. When the cells were in the logarithmic growth phase, the culture supernatant containing the monoclonal antibody was harvested. (8) Purification of monoclonal antibodies PBS (500 μL) was placed in an empty column, and after allowing the PBS to drain out, an approximately equal amount of affinity support for antibody purification ("Protein G Sepharose 4 Fast Flow" manufactured by GE Healthcare) was mixed thoroughly and placed in. The column was then washed once with 0.1 M glycine-HCl (pH 2.0, 2.5 mL) and twice with PBS (5 mL). 1 / 20 volume of 1M Tris (pH 8.0) was added to the culture supernatant of the positive clone, and a 15mL tube was placed under the column. In order to ensure the binding of the antibody and Protein G, about half of the solution was added to the column, and the remaining half was added after the solution had flowed out. The column was then washed three times with PBS (5mL). 1M Tris (pH 8.0, 500μL) was placed in a 5mL tube and set under the column. 0.1M glycine-HCl (pH 2.0, 2.5mL) was added to flow out the antibody, and the mixture was immediately mixed well and transferred to a concentration tube. The mixture was centrifuged while observing the state, and when it was concentrated to about 500μL, the lower phase was discarded and PBS (about 5mL) was added to the upper phase. After mixing well by inversion, it was further centrifuged to concentrate to about 300μL, transferred to a 1.5mL tube, and the total volume was adjusted to about 500μL with PSB. The concentration of the antibody was confirmed by electrophoresis. (9) Amino acid sequence of the monoclonal antibody Total RNA was extracted from the positive clones, and cDNA was prepared from the total RNA using a reagent composition for cDNA preparation ("SuperScript III First-Strand Synthesis SuperMix" manufactured by Thermo Fisher Scientific). From the cDNA, the CDR gene was amplified by reverse transcription PCR using a high-speed PCR enzyme ("KOD-Plus-Neo" manufactured by TOYOBO) and primers corresponding to the antigen complementarity determining region (CDR) of the antibody, and the base sequence and the amino acid sequence of the CDR were determined by outsourcing. The amino acid sequences of the CDRs of rat-derived anti-A1 beta casein antibody are shown in Table 2, the amino acid sequences of the CDRs of rat-derived anti-A1 / A2 beta casein antibody are shown in Table 3, and the amino acid sequences of the CDRs of mouse-derived anti-A1 beta casein antibody are shown in Table 4. Example 2: Quantification of A1 beta-casein by sandwich ELISA A1 milk containing only A1 beta-casein and A2 milk containing only A2 beta-casein were each diluted 100-fold and mixed to obtain the composition shown in Table 5 to prepare A1 / A2 beta-casein skim milk. The #27-1 anti-A1 / A2 beta casein antibody was diluted with PBS as a capture antibody, and a 1.5 μg / 100 μL solution was prepared and added to a 96-well plate at 100 μL / well. The plate was covered and incubated overnight at 37° C. Then, the liquid was discarded, washed twice with PBS (200 μL), and 1% BSA / PBS (200 μL) was added. The plate was covered and incubated for 1 hour at 37° C. or overnight at 4° C. Then, the liquid was discarded, washed twice with PBS (200 μL), and a milk sample (100 μL) diluted 100-fold with PBS was added. The plate was covered and incubated for 1.5 to 2 hours at 37° C. Then, the liquid was discarded, and washed three times with PBS (200 μL). Next, anti-A1 beta casein antibody #6-3 was diluted with 1% BSA / PBS to prepare a 1.5 μg / 100 μL solution as a detection antibody, and the resulting solution (100 μL) was added. The plate was covered and incubated at 37° C. for 1.5 to 2 hours. The liquid was discarded, and the plate was washed three times with PBS (200 μL). The HRP-labeled secondary antibody was diluted 20,000 times with 1% BSA / PBS, and the resulting diluted solution (100 μL) was added. The plate was covered and incubated at room temperature for 1 hour. The liquid was discarded and washed three times with PBS (200 μL). Separately, a PBS solution of 0.4 mg / mL o-phenylenediamine dihydrochloride + 0.012% hydrogen peroxide was prepared as a color-developing reagent, and 150 μL was added and allowed to stand at room temperature for 30 to 60 minutes. Thereafter, the reaction was stopped by adding 3 M sulfuric acid (50 μL), and the absorbance was measured at 492 nm. The measurement was performed three times on the same day, and the average value of the measured optical density (OD) values ​​was calculated. The results are shown in FIG. 1. In addition, in FIGS. 1 to 3, the horizontal axis indicates the amount of A1 beta-casein per 1 μL of the milk sample before dilution. As shown in FIG. 1, the relationship between the A1 beta-casein content and the measured OD value was y=-8×10 -5 x 2 +0.0138x+0.1229, and its coefficient of determination R 2 was very high at 0.998. In addition, even though the presence of A2 beta casein acts as an inhibitor on the measurement of A1 beta casein, when the sample contained a relatively large amount of A2 beta casein, specifically, even when A1:A2=1:30-50, the OD value was measured with a sufficiently significant difference compared to the measured OD value of the sample not containing A1 beta casein. Generally, A2 milk in which the influence of A1 beta casein is reduced refers to milk in which the ratio of A1 beta casein to beta casein is suppressed to 30% or less, and therefore, according to the present invention, it has been shown that the beta casein contained in milk can be sufficiently evaluated. Note that, from the beta casein concentration in the measurement sample, the actual measurement target milk may be defatted, diluted 10,000 times, and then measured by ELISA under the above conditions. Example 3: Quantification of A1 beta-casein by sandwich ELISA ELISA measurement was performed in the same manner as in Example 2, except that #17-2 anti-A1 beta casein antibody was used as the capture antibody instead of the anti-A1 / A2 beta casein antibody, and #6-3 anti-A1 beta casein antibody was used as the detection antibody. The results are shown in Figure 2. As shown in the results in Figure 2, the use of anti-A1 beta casein antibody as the capture antibody gave similar results to those obtained when anti-A1 / A2 beta casein antibody was used. Specifically, there was a correlation between the A1 beta casein content and the measured OD value of y = -7 x 10 -5 x 2 +0.0135x+0.1273 is obtained, and the coefficient of determination R 2 was very high at 0.9996. Also, a curve very similar to that in Example 2 was obtained, demonstrating that the combination of #17-2 anti-A1 beta-casein antibody and #6-3 anti-A1 beta-casein antibody makes it possible to detect A1 beta-casein in milk feed containing A2 beta-casein. Example 4: Quantification of A1 beta-casein by sandwich ELISA ELISA measurement was performed in the same manner as in Example 2, except that rHis#4-2 anti-A1 beta casein antibody was used as the capture antibody and mHis#21-8 anti-A1 beta casein antibody was used as the detection antibody. The results are shown in FIG. As shown in FIG. 3, the results were similar to those of Examples 2 and 3. Specifically, the relationship between the A1 beta-casein content and the measured OD value was y=-6×10 -5 x 2 +0.012x+0.1312, and its coefficient of determination R 2 The value was very high at 0.9939. Also, a curve very similar to that in Examples 2 and 3 was obtained. However, in Examples 2 and 3, in the milk samples containing 200 ng / μL or more of A1 beta-casein before dilution, the value was 2×10 -2 In this example, A1 beta casein was detectable in milk samples containing 1000 ng / μL or more of A1 beta casein before dilution, whereas the measured OD values ​​showed that A1 beta casein was detectable in milk samples containing 1000 ng / μL or more of A1 beta casein before dilution and 1×10 -1 A1 beta-casein was detectable in milk samples containing ng / μL or more of A1 beta-casein. Example 5: Quantification of A1 beta-casein by sandwich ELISA A1 milk containing only A1 beta-casein and A2 milk containing only A2 beta-casein were each diluted 100-fold and mixed to obtain the composition shown in Table 6, to prepare A1 / A2 beta-casein milk. The milk samples were used as they were, without being skimmed. ELISA measurements were performed in the same manner as in Example 2, except that mHis#6-3A1 beta casein antibody was used as the detection antibody and non-skimmed milk samples were used. The results are shown in Table 6 and FIG. As shown in Table 6 and FIG. 4, the relationship between the A1 beta casein content and the measured OD value was y=-3.1×10 -3 x 2 The approximate equation of +0.1339x+0.1847 is obtained, and the coefficient of determination R 2 The value was very high at 0.9998. It was also revealed that the measurement is possible not only for skim milk but also for raw milk. Furthermore, it was shown that the present invention can detect A1 β-casein in raw milk, so long as the mass ratio of A1 β-casein to A2 β-casein is 1 / 200 or more. Example 6: Quantification of A1 beta-casein by sandwich ELISA A1 milk containing only A1 beta-casein and A2 milk containing only A2 beta-casein were each diluted 100-fold and mixed to obtain the composition shown in Table 6, to prepare A1 / A2 beta-casein milk. The milk samples were used as they were, without being skimmed. ELISA measurements were performed in the same manner as in Example 2, except that mHis#6-3A1 beta casein antibody was used as the detection antibody and non-skimmed milk samples were used. The results are shown in Table 7 and FIG. As shown in Table 7 and FIG. 5, the relationship between the A1 beta casein content and the measured OD value was y=-2.0×10 -4 x 2 +0.025x+0.1696, and its coefficient of determination R 2The value was very high at 0.9653. It was also revealed that the measurement is possible not only for skim milk but also for raw milk. Furthermore, it was shown that the present invention can detect A1 β-casein in raw milk, so long as the mass ratio of A1 β-casein to A2 β-casein is 1 / 100 or more. Example 7 We have prepared rat-derived anti-A1 beta casein antibody (I), rat-derived anti-A1 / A2 beta casein antibody (III), and mouse-derived anti-A1 beta casein antibody (II) having the following CDR amino acid sequences. Each antibody has excellent selective binding ability to A1 beta casein or both A1 beta casein and A2 beta casein.

Claims

1. A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising any one of the amino acid sequences of SEQ ID NOs: 4 to 6, 39 to 49, a heavy chain complementarity determining region 2 comprising any one of the amino acid sequences of SEQ ID NOs: 10, 11, 73 to 89, 111, and a heavy chain complementarity determining region 3 comprising any one of the amino acid sequences of SEQ ID NOs: 17 to 19, 115 to 128, and a light chain variable region including a light chain complementarity determining region 1 having an amino acid sequence of any one of SEQ ID NOs: 25 to 28, 164 to 170, and 191; a light chain complementarity determining region 2 having an amino acid sequence of any one of Asn-Ala-Asn, Asp-Thr-Ser, Leu-Val-Ser, Ser-Gly-Ser, Asn-Pro-Asn, Glu-Ile-Ser, Trp-Met-Ser, Tyr-Ala-Asn, Tyr-Ala-Ser, Leu-Ala-Ser, and Gln-Val-Ser; and a light chain complementarity determining region 3 having an amino acid sequence of any one of SEQ ID NOs: 31 to 33, and 193 to 204; A monoclonal antibody characterized by binding to A1 beta-casein.

2. A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising any one of the amino acid sequences of SEQ ID NOs: 8, 9, and 56 to 72, a heavy chain complementarity determining region 2 comprising any one of the amino acid sequences of SEQ ID NOs: 14 to 16, and 97 to 114, and a heavy chain complementarity determining region 3 comprising any one of the amino acid sequences of SEQ ID NOs: 23, 24, and 140 to 163, and a light chain variable region including a light chain complementarity determining region 1 having an amino acid sequence of any one of SEQ ID NOs: 30, 176 to 192, a light chain complementarity determining region 2 having an amino acid sequence of any one of Trp-Ala-Ser, Lys-Val-Ser, Ala-Thr-Ser, and Leu-Val-Ser, and a light chain complementarity determining region 3 having an amino acid sequence of any one of SEQ ID NOs: 37, 38, and 212 to 227; A monoclonal antibody characterized by binding to A1 beta-casein.

3. A heavy chain variable region comprising a heavy chain complementarity determining region 1 comprising any one of the amino acid sequences of SEQ ID NOs: 6, 7, 50 to 55, and 60, a heavy chain complementarity determining region 2 comprising any one of the amino acid sequences of SEQ ID NOs: 12, 13, and 90 to 96, and a heavy chain complementarity determining region 3 comprising any one of the amino acid sequences of SEQ ID NOs: 20 to 22, and 129 to 139; and a light chain variable region comprising a light chain complementarity determining region 1 comprising any one of the amino acid sequences of SEQ ID NOs: 28, 29, and 170 to 175; a light chain complementarity determining region 2 comprising any one of the amino acid sequences of Asn-Thr-Asn, Arg-Val-Ser, Asn-Lys-Asn, Asn-Ser-Asn, Lys-Ala-Asn, Gly-Ala-Thr, Gln-Val-Ser, and Leu-Val-Ser; and a light chain complementarity determining region 3 comprising any one of the amino acid sequences of SEQ ID NOs: 34 to 36, and 205 to 211; A monoclonal antibody characterized by binding to A1 beta-casein and A2 beta-casein.

4. The monoclonal antibody according to any one of claims 1 to 3, further comprising an Fc region.

5. A hybridoma comprising a nucleic acid encoding the heavy chain variable region and the light chain variable region of the monoclonal antibody according to any one of claims 1 to 3.

6. 1. A method for detecting A1 beta-casein in a milk sample, comprising the steps of: A method comprising the step of mixing the milk sample with the monoclonal antibody of claim 1 or 2.

7. Further, a step of selecting a detection antibody from the monoclonal antibodies according to claim 1 or 2, and selecting a capture antibody having an epitope different from that of the detection antibody from the monoclonal antibodies according to any one of claims 1 to 3; immobilizing the capture antibody on a plate; and 7. The method of claim 6, further comprising the step of mixing the detection antibody with the mixture of the capture antibody and the milk sample.