Fc-Modified IgG1 Antibodies for Cooperative Binding and Cell Killing
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Solution Overview
Problem
Humanized IgG1 antibodies derived from mouse IgG3 antibodies lose direct cell killing and functional affinity due to the absence of intermolecular cooperativity present in mouse IgG3 isotypes, which is crucial for enhanced binding to glycan antigens and cytotoxic effects on cancer cells.
Innovation Solution
Transfer key residues from the CH2 and CH3 domains of mouse IgG3 antibodies into human IgG1 antibodies to recreate intermolecular cooperativity, enhancing functional affinity and direct cytotoxicity by modifying specific amino acids in the Fc region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mouse IgG3 isotype is used to achieve direct cell killing and enhanced functional affinity, then cytotoxicity and binding strength are improved, but humanization to reduce immunogenicity becomes difficult
Solution Approach 1:
The patent applies local quality by making specific amino acid substitutions only in the Fc region (positions 232-447) while keeping the antigen-binding variable regions intact. This localized modification approach allows the antibody to gain human IgG1 compatibility in the Fc region while retaining the ability to form functional oligomers through specific residue changes, thus resolving the contradiction between humanization and direct cell killing ability
Solution Approach 2:
The patent changes specific amino acid parameters (residues) in the Fc region from mouse IgG3 to human IgG1 compatible variants. By modifying parameters such as charge, hydrophobicity, and steric properties at specific positions (e.g., positions 232, 235, 236, 239, 240, 242, 243, 244, 246, 247, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447), the patent enables humanized antibodies to regain oligomerization capability and direct cell killing function
2Adaptability or versatility
If human IgG1 isotype is used for humanization, then immunogenicity is reduced, but direct cell killing and functional affinity are lost
Solution Approach 1:
The patent changes specific amino acid parameters in the Fc region of human IgG1 to create variants that can form non-covalent oligomers. By modifying residues at positions that control Fc-Fc interactions (such as positions 232, 235, 236, 239, 240, 242, 243, 244, 246, 247, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447), the patent enables human IgG1 to acquire mouse IgG3-like oligomerization properties while maintaining human compatibility
Solution Approach 2:
The patent segments the antibody molecule into variable regions (antigen-binding) and constant Fc regions, applying different design strategies to each. The variable regions are kept as human or humanized sequences for low immunogenicity, while the Fc region is engineered with specific amino acid substitutions to enable oligomerization and direct cell killing. This segmentation allows independent optimization of immunogenicity and cytotoxicity functions
3Reliability
If mouse IgG3 Fc region is transferred to achieve oligomerization, then functional affinity is enhanced, but antibody complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by making specific amino acid substitutions only in the Fc region (positions 232-447) while keeping the antigen-binding variable regions intact. This localized modification approach allows the antibody to gain human IgG1 compatibility in the Fc region while retaining the ability to form functional oligomers through specific residue changes, thus resolving the contradiction between humanization and direct cell killing ability
Solution Approach 2:
The patent changes specific amino acid parameters (residues) in the Fc region from mouse IgG3 to human IgG1 compatible variants. By modifying parameters such as charge, hydrophobicity, and steric properties at specific positions, the patent enables humanized antibodies to regain oligomerization capability and direct cell killing function with simplified structure
Data Source
AI summary
The present invention relates to the identification of key residues within mouse IgG3 antibodies (mAbs) that are responsible for intermolecular cooperativity and their transfer into IgG1 antibodies in order to enhance their functional affinity and direct a cell killing.