0 9 Inhibitor Inhibitor NNP 10 11 ( ( ( 11 13 IK IK NNP 13 14 ) ) ) 15 17 of of IN 18 27 IFN-gamma IFN-gamma NNP 28 35 induced induced JJ 36 39 HLA HLA NNP 40 45 class class NN 46 48 II ii CD 49 57 antigens antigen NNS 58 68 expression expression NN 69 73 also also RB 74 82 inhibits inhibit VBZ 83 86 HLA HLA NNP 87 92 class class NN 93 95 II ii CD 96 108 constitutive constitutive JJ 109 119 expression expression NN 120 122 in in IN 123 126 the the DT 127 132 human human JJ 133 137 Raji Raji NNP 138 139 B B NNP 140 144 cell cell NN 145 149 line line NN 149 150 . . . 152 155 The the DT 156 166 expression expression NN 167 169 of of IN 170 175 major major JJ 176 194 histocompatibility histocompatibility NN 195 202 complex complex NN 203 204 ( ( ( 204 207 MHC MHC NNP 207 208 ) ) ) 209 214 class class NN 215 217 II ii CD 218 226 antigens antigen NNS 227 229 is be VBZ 230 242 constitutive constitutive JJ 243 245 in in IN 246 258 professional professional JJ 259 266 antigen antigen NN 267 277 presenting presenting NN 278 283 cells cell NNS 284 285 ( ( ( 285 289 APCs APC NNPS 289 290 ) ) ) 291 294 but but CC 295 298 can can MD 299 303 also also RB 304 306 be be VB 307 314 induced induce VBN 315 317 by by IN 318 334 interferon-gamma interferon-gamma NN 335 336 ( ( ( 336 345 IFN-gamma IFN-gamma NNP 345 346 ) ) ) 347 349 on on IN 350 353 the the DT 354 362 majority majority NN 363 365 of of IN 366 369 the the DT 370 373 non non JJ 374 386 professional professional JJ 387 391 APCs apc NNS 392 393 ( ( ( 393 397 e.g. e.g. FW 398 409 fibroblasts fibroblast NNS 409 410 ) ) ) 410 411 . . . 412 414 We we PRP 415 419 have have VBP 420 428 recently recently RB 429 442 characterised characterise VBN 443 444 a a DT 445 448 new new JJ 449 455 factor factor NN 456 462 called call VBN 463 465 IK IK NNP 466 471 which which WDT 472 474 is be VBZ 475 477 an an DT 478 487 efficient efficient JJ 488 497 inhibitor inhibitor NN 498 500 of of IN 501 510 IFN-gamma IFN-gamma NNP 511 520 induction induction NN 521 523 of of IN 524 527 MHC MHC NNP 528 533 class class NN 534 536 II ii CD 537 545 antigens antigen NNS 546 556 expression expression NN 556 557 . . . 558 562 Here here RB 562 563 , , , 564 566 we we PRP 567 578 demonstrate demonstrate VBP 579 580 a a DT 581 586 novel novel JJ 587 591 role role NN 592 595 for for IN 596 598 IK IK NNP 599 601 in in IN 602 605 MHC MHC NNP 606 611 class class NN 612 614 II ii CD 615 625 expression expression NN 626 631 since since IN 632 647 over-expression over-expression NN 648 650 of of IN 651 655 this this DT 656 663 protein protein NN 664 666 by by IN 667 673 stable stable JJ 674 686 transfection transfection NN 687 691 into into IN 692 697 human human JJ 698 699 B B NNP 700 705 cells cell NNS 706 709 led lead VBD 710 712 to to TO 713 714 a a DT 715 720 total total JJ 721 734 disappearance disappearance NN 735 737 of of IN 738 750 constitutive constitutive JJ 751 754 MHC MHC NNP 755 760 class class NN 761 763 II ii CD 764 768 mRNA mRNA NNP 769 779 expression expression NN 779 780 . . . 781 784 The the DT 785 790 class class NN 791 793 II ii CD 794 808 transactivator transactivator NN 809 810 ( ( ( 810 815 CIITA CIITA NNP 815 816 ) ) ) 817 819 is be VBZ 820 829 necessary necessary JJ 830 833 for for IN 834 838 both both CC 839 851 constitutive constitutive JJ 852 855 and and CC 856 865 IFN-gamma IFN-gamma NNP 866 873 induced induce VBD 874 877 MHC MHC NNP 878 883 class class NN 884 886 II ii CD 887 898 expressions expression NNS 898 899 . . . 900 911 Examination Examination NNP 912 914 of of IN 915 920 CIITA CIITA NNP 921 925 mRNA mRNA NNP 926 928 in in IN 929 931 IK IK NNP 932 938 stably stably RB 939 950 transfected transfecte VBN 951 957 clones clone NNS 958 966 revealed reveal VBD 967 968 a a DT 969 975 marked marked JJ 976 985 reduction reduction NN 986 988 of of IN 989 994 CIITA CIITA NNP 995 999 mRNA mRNA NNP 1000 1013 transcription transcription NN 1013 1014 . . . 1015 1020 Taken take VBN 1021 1029 together together RB 1030 1035 these these DT 1036 1043 results result NNS 1044 1055 demonstrate demonstrate VBP 1056 1060 that that IN 1061 1064 the the DT 1065 1067 IK IK NNP 1068 1075 protein protein NN 1076 1081 plays play VBZ 1082 1083 a a DT 1084 1087 key key JJ 1088 1092 role role NN 1093 1095 in in IN 1096 1099 the the DT 1100 1112 constitutive constitutive JJ 1113 1123 expression expression NN 1124 1126 of of IN 1127 1130 MHC MHC NNP 1131 1136 class class NN 1137 1139 II ii CD 1140 1148 antigens antigen NNS 1149 1152 and and CC 1153 1157 that that IN 1158 1168 inhibition inhibition NN 1169 1176 induced induce VBN 1177 1179 by by IN 1180 1182 IK IK NNP 1183 1185 is be VBZ 1186 1194 upstream upstream JJ 1195 1197 of of IN 1198 1203 CIITA CIITA NNP 1204 1206 in in IN 1207 1211 this this DT 1212 1222 regulatory regulatory JJ 1223 1230 pathway pathway NN 1230 1231 . . .