The present invention relates to a polypeptide comprising a mutated Fc region and exhibiting a functional activity mediated by the Fc region that has been modified compared with that of a parent polypeptide, characterized in that said Fc region comprises at least one combination of 2 mutations, wherein said combination is chosen from: (i) a mutation chosen from 326E, 326T, 352L, 378V, 378T, 396L, 397M, 421T, 334N, 334R, 307N and 394P； and (ii) at least one mutation chosen from 226Y, 227S, 230S, 231V, 234P, 2431, 243L, 246R, 246E, 247T, 248E, 253F, 254F 255W, 259A, 261R, 262A, 263A, 266M, 267N, 267G, 274E, 274R, 276S, 278H, 379A, 282A, 283G, 284L, 2861, 286Y, 287T, 288E, 288R, 290E, 298N, 302A, 305 A, 307P, 308A, 3081, 308G, 309P, 312G, 315D, 316D, 319H, 320T, 320R, 320M, 322E, 3231, 333G, 339T, 349S, 325S, 334N, 334R, 336T, 340E, 343S, 345G, 349H, 350A 352S, 359A, 361H, 362R, 3631, 366A, 373D, 375R, 377T, 378V, 378T, 380G, 383R, 385R, 389S, 389T, 392R, 393A, 3931, 394P, 396L, 3971, 397M, 398P, 405V, 405L, 410R, 412M, 414R, 421T, 423L, 423Y, 423S, 423P, 428T, 431V, 431T, 434K, 434S, 435R, 436H, 439R, 440G, 440N, 442F, 442P and 447N, the numbering being that of the EU index or equivalent in Kabat and with the condition that the mutation (i) does not take place on the same amino acid as the mutation (ii). The present invention also relates to the use of such a polypeptide, to compositions comprising same, and to methods for preparing such a polypeptide.
