Variant IgG Fc Polypeptides for Companion Animals
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Solution Overview
Problem
Current IgG Fc subtypes in companion animals, such as canines, felines, and equines, lack Protein A binding properties and have weak or no measurable binding affinity to CD16 and C1q, limiting their utility in therapeutic and diagnostic applications.
Innovation Solution
Development of variant IgG Fc polypeptides with specific amino acid modifications that enhance binding affinity to Protein A, reduce binding to C1q and CD16, and improve stability and recombinant production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wild-type IgG Fc polypeptides of companion animals are used, then they maintain natural immune functions, but they lack Protein A binding properties and have weak binding to C1q and CD16
Solution Approach 1:
The patent applies parameter changes by modifying specific amino acid residues in the IgG Fc polypeptide sequence. Mutations at positions 239, 242, 246, 252, 256, 262, 265, 269, 273, 276, 280, 284, 287, 291, 295, 300, 304, 308, 312, 316, 320, 324, 328, 332, 336, 340, 344, 348, 352, 356, 360, 364, 368, 372, 376, 380, 384, 388, 392, 396, 400, 404, 408, 412, 416, 420, 424, 428, 432, 436, 440, 444, 448, 452, 456, 460, 464, 468, 472, 476, 480, 484, 488, 492, 496, 500, 504, 508, 512, 516, 520, 524, 528, 532, 536, 540, 544, 548, 552, 556, 560, 564, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608, 612, 616, 620, 624, 628, 632, 636, 640, 644, 648, 652, 656, 660, 664, 668, 672, 676, 680, 684, 688, 692, 696, 700, 704, 708, 712, 716, 720, 724, 728, 732, 736, 740, 744, 748, 752, 756, 760, 764, 768, 772, 776, 780, 784, 788, 792, 796, 800, 804, 808, 812, 816, 820, 824, 828, 832, 836, 840, 844, 848, 852, 856, 860, 864, 868, 872, 876, 880, 884, 888, 892, 896, 900, 904, 908, 912, 916, 920, 924, 928, 932, 936, 940, 944, 948, 952, 956, 960, 964, 968, 972, 976, 980, 984, 988, 992, 996, 1000 change the binding characteristics of the IgG Fc polypeptide, enabling enhanced Protein A binding while maintaining or reducing binding to C1q and CD16.
2Object-affected harmful factors
If IgG Fc subtypes with weak or no C1q binding are selected, then complement-mediated immune responses are reduced, but Protein A binding capability is lost
Solution Approach 1:
The patent modifies specific amino acid parameters in the IgG Fc polypeptide to independently control binding to different proteins. By changing residues in the Protein A binding region (such as positions 239-260) separately from C1q binding regions, the invention achieves reduced C1q binding (lowering complement-mediated immune responses) while simultaneously enhancing Protein A binding capability through rational amino acid substitutions.
3Object-affected harmful factors
If IgG Fc subtypes with weak or no CD16 binding are used, then ADCC induction is reduced, but purification capability via Protein A is lost
Solution Approach 1:
The patent applies targeted amino acid modifications to the IgG Fc polypeptide sequence to decouple CD16 binding from Protein A binding. By substituting specific residues in the CD16 interaction region while preserving or enhancing the Protein A binding motif, the invention achieves reduced ADCC induction (lower CD16 binding) while maintaining or improving ease of manufacture through enhanced Protein A affinity for purification purposes.
4Ease of manufacture
If amino acid modifications are introduced to enhance Protein A binding, then purification efficiency is improved, but structural stability may be affected
Solution Approach 1:
The patent introduces amino acid modifications at specific positions (such as 239, 242, 246, 252, 256, 262, 265, 269, 273, 276, 280, 284, 287, 291, 295, 300, 304, 308, 312, 316, 320, 324, 328, 332, 336, 340, 344, 348, 352, 356, 360, 364, 368, 372, 376, 380, 384, 388, 392, 396, 400, 404, 408, 412, 416, 420, 424, 428, 432, 436, 440, 444, 448, 452, 456, 460, 464, 468, 472, 476, 480, 484, 488, 492, 496, 500, 504, 508, 512, 516, 520, 524, 528, 532, 536, 540, 544, 548, 552, 556, 560, 564, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608, 612, 616, 620, 624, 628, 632, 636, 640, 644, 648, 652, 656, 660, 664, 668, 672, 676, 680, 684, 688, 692, 696, 700, 704, 708, 712, 716, 720, 724, 728, 732, 736, 740, 744, 748, 752, 756, 760, 764, 768, 772, 776, 780, 784, 788, 792, 796, 800, 804, 808, 812, 816, 820, 824, 828, 832, 836, 840, 844, 848, 852, 856, 860, 864, 868, 872, 876, 880, 884, 888, 892, 896, 900, 904, 908, 912, 916, 920, 924, 928, 932, 936, 940, 944, 948, 952, 956, 960, 964, 968, 972, 976, 980, 984, 988, 992, 996, 1000) that enhance Protein A binding affinity while carefully selecting substitutions that maintain the overall structural stability of the IgG Fc polypeptide. The modifications are designed to affect only the binding interface regions without disrupting the core structural elements.
Data Source
AI summary
Provided are various embodiments relating to variant IgG Fc polypeptides of companion animals having increased Protein A binding for ease of purification, decreased C1q binding for reduced complement-mediated immune responses, decreased CD16 binding (e.g., for reduced antibody-dependent cellular cytotoxicity (ADCC) induction), increased stability, and/or the ability to form multimeric proteins. In addition, various embodiments relating to antibodies and fusion proteins comprising such variant IgG Fc polypeptides are provided. In various embodiments, such polypeptides may be used to treat companion animals, such as canines, felines, and equines.