苦参碱诱导自然杀伤细胞对白血病K562细胞杀伤的实验研究

目的 探讨中药苦参碱对人自然杀伤（NK）细胞体外杀伤白血病细胞的作用及可能的分子机制.方法 以人慢性粒细胞白血病K562细胞为靶细胞,采用CFSE/PI双染色法流式细胞术检测不同质量浓度（02、0.5、0.8 mg/ml）苦参碱处理后,人NK细胞在不同效靶比下对K562细胞的体外杀伤活性.流式细胞术分析不同浓度苦参碱处理24 h对NK细胞主要活化性受体NKG2D和抑制性受体CD158a、CD158b表达的影响及K562细胞膜上NKG2D配体MICA/B、ULBP1、ULBP 2、ULBP 3表达的改变.结果 效靶比为5∶1时,NK细胞对0.2、0.5和0.8 mg/ml苦参碱处理后的K562细胞杀伤率分别为32.8％、38.1％和40.5％,较处理前均有不同程度增高（29.2％）;但进一步增加效靶比（10：1）后,NK细胞杀伤活性改变差异无统计学意义（P＞0.05）.苦参碱处理24 h,NK细胞抑制性受体CD158a、CD158b的表达均较处理前降低,而活化受体NKG2D的表达则增高.K562细胞表面NKG2D配体ULBP1和ULBP2分子的表达也较处理前增高（平均荧光强度分别为174.33±39.93比275.67±32.88,517.6±47.97比1368.6±49.43,P＜0.05）.结论 苦参碱可增强NK细胞对白血病K562细胞的体外杀伤活性,其机制可能与NK细胞受体及配体表达调节作用有关.     

人胶质瘤细胞U251逃逸NK细胞免疫杀伤机制的初步探讨

目的 探讨人神经胶质瘤细胞U251逃逸同种异体NK细胞免疫杀伤的机制。方法以K562细胞为对照,应用LDH释放法检测不同效靶比时NK细胞体外杀伤U251细胞的活性。用RT-PCR检测K562和U251细胞MHC-I类链相关分子A和B（MICA／B）、人巨细胞病毒糖蛋白UL16结合蛋白（ULBP1～3）基因,用流式细胞仪检测两细胞MICA／B、ULBP1～3和HLA-I分子的表达情况。效靶比20：1时用单抗分别阻断K562和U251细胞表面MICA、MICB、ULBP1、ULBP2、ULBP3和HLA—I类分子,观察NK细胞对其杀伤活性的变化。结果同一效靶比时NK细胞杀伤U251细胞的活性明显低于杀伤K562细胞的活性,两者之间差异有统计学意义（P〈0．05）;K562和U251细胞均表达基因MICA／B和ULBP1～3,但U251细胞仅低表达ULBP2分子。用单抗封闭MICA／B和ULBP1～3分子后,NK细胞对K562细胞的杀伤活性明显降低,对U251细胞的杀伤活性无明显改变。封闭HLA-I类分子后NK细胞对U251细胞的杀伤活性明显上升,对K562细胞的杀伤活性无明显改变。结论U251细胞逃逸NK细胞免疫杀伤机制可能是由于U251细胞高表达HLA-I类分子,不表达NKG2D的配体MICA／B和ULBP1～3。     

放射线照射后NK-92 细胞对人宫颈癌细胞体外杀伤活性的研究

 目的 研究放射线照射后NK-92细胞对人宫颈癌细胞的体外杀伤活性。方法 应用医用电子直线加速器对NK-92细胞进行照射处理(0、400cGy)后，以体外培养人宫颈癌细胞系Hela为靶细胞，以NK-92的敏感细胞株K562作为对照，应用4h^51Cr释放法检测不同效靶比情况下NK-92细胞的杀伤活性。结果 NK-92细胞0cGy照射组，效靶比较低时(1：1、5：1)对Hela细胞杀伤率为15％～33％，随效靶比升高，杀伤率随之上升，10：1时杀伤率显著上升为47％，20：1时杀伤率仅上升了3％；对于K562细胞，杀伤率为33％～69％。400cGy组照射后2d，NK-92细胞对Hela细胞不同效靶比的杀伤率与0cGy组相比稍有降低，其总体杀伤率为14％～47％，对K562细胞杀伤范围在30％～60％之间。结论 放射线照射后的NK-92细胞对人宫颈癌Hela细胞系具有一定的杀伤活性。     

NK细胞杀伤人骨髓瘤RPMI8226细胞的活性及其可能的机制

目的:研究同种异体NK细胞对人骨髓瘤RPMI 8226细胞的杀伤活性及其可能的机制。方法:LDH释放法检测NK细胞对RPMI 8226细胞和人白血病K562细胞的杀伤活性,流式细胞术和RT-PCR法分别检测K562和RPMI 8226细胞中NKG2D配体和HLA-Ⅰ类分子的表达;阻断K562和RPMI 8226细胞中NKG2D配体的表达后,检测NK细胞的杀伤活性。结果:NK细胞对RPMI 8226靶细胞的杀伤活性明显低于对K562靶细胞的杀伤(P<0.01)。K562细胞高表达NKG2D配体,不表达HLA-Ⅰ类分子;RPMI 8226细胞低表达NKG2D配体,高表达HLA-Ⅰ类分子,其HLA基因型为A 01,66;B 58,58;Cw 03,06。阻断NKG2D配体后NK细胞杀伤K562细胞的活性明显降低(P<0.01),而杀伤RPMI 8226细胞的活性无明显改变;阻断HLA-Ⅰ类分子,NK细胞杀伤K562细胞的活性无变化,而杀伤RPMI 8226细胞的活性明显提高(P<0.01)。结论:NK细胞杀伤RPMI 8226细胞的活性较低,其机制与RPMI 8226细胞高表达HLA-Ⅰ类分子、低表达NKG2D配体有关。     

NKG2D介导NK 细胞对鼻咽癌细胞杀伤作用的体外研究

 目的 探讨鼻咽癌CNE2细胞表面HLA-Ⅰ类分子表型和NKG2D配体的表达情况，进一步了解其对同种异体NK细胞杀伤活性的影响。方法 流式细胞仪检测NKG2D的配体MICA、MICB、ULBP1、ULBP2、ULBP3在K562、CNE2细胞的表达情况。PCR-SSP法分析CNE2细胞HLA-A、B、Cw分型和NK细胞KIR分型。LDH释放法测定5例健康者NK细胞在不同效靶比时对K562、CNE2细胞的杀伤活性，效靶比20：1时观察抗NKG2D配体的单抗对NK细胞杀伤K562、CNE2细胞活性的影响。结果 CNE2细胞表达MICA、MICB、ULBP2，不表达ULBP1、ULBP3。K562细胞表面表达MICA、MICB、ULBP1、ULBP2、ULBP3。5例健康者NK细胞抑制性KIR与CNE2细胞表面的HLA-Ⅰ类分子之间存在错配。效靶比5：1、10：1、20：1、30：1时NK细胞对K562、CNE2细胞的杀伤活性分别为（29．02±0．45）％、（10．50±2．17）％；（44．43±1．36）％、（27．68±1．47）％；（57．82±1．35）％、（36．99±3．13）％：（71．24±2．36）％、（55．00±2．20）％，在各效靶比时NK细胞对K562细胞的杀伤活性较CNE2细胞明显增强（P=0．000）；在效靶比20：1时anti-MICA、anti-MICB、anti-ULBP1、anti—ULBP2、anti-ULBP3可明显抑制NK细胞对K562细胞的杀伤活性，与阻断前相比有显著性差异（P=0．000）；anti—MICA、anti—MICB、anti—ULBP2可明显抑制NK细胞对CNE2细胞的杀伤活性，与阻断前相比有显著性差异（P〈0．01），但anti—ULBP1、anti—ULBP3不能阻断NK细胞对CNE2细胞的杀伤活性。结论 NKG2D配体影响NK细胞对靶细胞的杀伤活性，提高NKG2D配体的表达有可能提高NK细胞的抗肿瘤活性。     

骨髓瘤RPMI 8226细胞体外逃逸NK细胞免疫杀伤机制的初步研究

目的:探讨骨髓瘤细胞RPMI 8266逃逸NK细胞免疫杀伤的机制。方法:流式细胞仪检测K562和8266细胞表面MICA/B、ULBP1～3和HLA-Ⅰ类分子的表达。4hLDH释放法测定效靶比20∶1时阻断前后NK细胞对2种细胞杀伤活性变化。观察效靶比20∶1时NK细胞对药物处理后RPMI 8226细胞杀伤活性变化、RPMI 8226细胞表面NKG2D配体和HLA-Ⅰ类分子的表达及NK细胞对RPMI 8266细胞的克隆形成率的影响。结果:K562细胞高表达MICA/B和ULBP 1～3分子;RPMI 8266细胞表达HLA-Ⅰ类分子,2株细胞NKG2D配体表达差异有统计学意义,P<0.001。单抗分别阻断MICA/B、ULBP 1～3分子后,效靶比为20∶1时NK细胞对K562细胞的杀伤活性明显降低,P值均<0.05;对RPMI 8266细胞的杀伤活性基本无变化,P值均>0.05。抗W6/32单抗封闭8266细胞表面HLA-Ⅰ类分子后,NK细胞对K562细胞的杀伤活性无上升(P=0.721),而对RPMI 8266细胞的杀伤活性上升,P=0.000。1/2IC50的三氧化二砷处理后RPMI8226细胞ULBP...     

一种简单γδT细胞扩增培养方法及其抗肿瘤生物学功能研究

目的 :建立一种特异快速地诱导扩增人外周血γδT细胞的方法 ,并比较了γδT细胞 ,NK和LAK细胞的抗肿瘤的生物学特性。方法 :收集用不同单抗分别包被粘附的细胞 ,然后通过MACS细胞分选仪的分选 ,获取的细胞进行细胞增殖动力学、细胞表型、细胞杀伤活性的测定以及单抗阻断效应的分析。结果 :经MACS分离得到的γδT细胞 ,培养 2周后细胞数扩增 6 0 0～ 80 0倍 ,CD3,CD8和γδ细胞表达阳性率分别是 72 .2 9% ,5 8.0 2 %和 6 5 .98%。γδT细胞对NK敏感细胞K5 6 2以及NK不敏感细胞Raji和XG 7这 3种不同靶细胞均有较高的杀伤率 ,分别为 35 .98% ,5 2 .2 7%和 6 9.0 8% ;NK细胞对此 3种细胞的杀伤率分别是 45 2 1% ,12 .34%和 11.94% ;LAK细胞的杀伤率分别为 44 .0 1% ,2 9.2 7%和 2 5 .6 8%。γδT细胞对经MHC Ⅰ类单抗阻断前后的K5 6 2 ,Raji和XG 73种靶细胞的杀伤率无明显改变。结论 :γδT细胞、NK细胞和LAK细胞都具有一定的非特异性杀伤肿瘤细胞的作用 ;γδT细胞对MHC Ⅰ类单抗阻断后的肿瘤细胞的杀伤无明显变化。提示γδT细胞较NK细胞和LAK细胞有更广泛的抗瘤谱     

肿瘤患者自体抗CD3抗体 IL-2诱导LAK与LAK的比较及在生物治疗中的意义

本研究旨在观察抗CD3抗体联合IL-2诱导LAK在肿瘤生物治疗中的应用前景.效应细胞的制备:本院实体瘤患者外周血PBLC,选用RPMI 1640、15%人 AB血清,分别经(1)IL-2 1000U/ml:(2)CD3抗体300μg/ml IL-2 1000U/ml诱导培养2周.免疫表型分析:采用DAKO公司荧光抗体CD3.CD4、CD8、CD56、CD25、CD45RO/CD8对培养2周的CD3LAK与LAK细胞进行直接免疫荧光方法流式细胞仪检测.靶细胞抑制力:采用细胞增殖检测试剂盒I Cat No.1465007(MTT),Raji、K562为靶细胞,LAK、CD3LAK为效应细胞,效靶比例为10、5、1:1.     

小儿白血病NK、LAK细胞活性的研究

本文对22例正常人及21例白血病患儿NK、LAK细胞活性检测结果表明,缓解期白血病患儿NK、LAK细胞活性正常,活动期白血病患儿NK、LAK细胞活性低下,分别为10.4%±9.7%(正常值28%±13.4%)P<0.01,对K562为34.3%±14.4%(正常值52.8%±15.3%)P<0.001,对Raji为32.6%±14.7%(正常值52.8%±14.3%)P<0.01。NK细胞活性低下的原因与血液中存在的抑制淋巴细胞无关,可能系NK细胞本身缺陷所致,rIL—2能恢复活动期白血病NK细胞活性。     

红细胞与LAK细胞共培养上清对Raji细胞的细胞毒作用

目的 研究人红细胞(RBC)对LAK细胞杀伤活性的影响及RBC及LAK细胞共培养上清(R—LAK—S)对Raji细胞的细胞毒作用。方法 采用MTT比色法测定LAK细胞的杀伤活性和R—LAK—S的细胞毒性。结果 不同浓度的RBC对LAK细胞的杀伤活性都有促进作用(P<0.01),随着RBC浓度的增加,其促进作用加强。不同RBC:PBMC比例的R—LAK—S对Raji细胞均有细胞毒性,且随RBC浓度的增加以及与Raji细胞作用时间的延长,其对Raji细胞的细胞毒也增强。结论 人RBC能增强LAK细胞的杀伤活性,R—LAK—S对Raji细胞有细胞毒性。     

健康人和骨肉瘤病人来源的LAK细胞体外抗瘤作用

采用５１Ｃｒ释放试验对健康人和骨肉瘤病人外周血单个核细胞（ＰＢＭ）在重组白细胞介素－２（ｒＩＬ－２）条件下，ＬＡＫ细胞的诱导形成及对４种传代瘤细胞的体外杀伤活性进行探讨。实验结果表明：２种来源ＬＡＫ细胞对Ｋ５６２（人慢性髓样红白血病细胞系）、ＳＭＭＣ７７２１（人肝癌细胞系）、ＬＡＸ（人肺腺癌细胞系）的杀伤活性均在５５％以上（按效靶比例５０：１），而对ＯＳ细胞（人骨肉瘤细胞系）的活性普遍低下，杀伤率低于３５％。结果证实：１）健康人和骨肉瘤病人的ＰＢＭ均能在ｒＩＬ－２条件下诱导形成具有广谱抗瘤活性的ＬＡＫ细胞群，二者的杀伤格局和效力相近。２）骨肉瘤细胞本身对ＬＡＫ细胞的杀伤作用存在强烈抗性。     

Natural cytotoxicity in humans: susceptibility of freshly isolatd tumor cells to lysis

The cytotoxic potential of blood lymphocyters from healthy donors was tested against freshly isolated lung cancer cells and the erythroleukemia K562 cell line in short-term 51Cr release assays conducted at an effector:target ratio of 50:1. Most donors exhibited significant activity against K6-562 cells. By contrast, fresh tumor cells were refractory, only 6 of 30 showing significant cytotoxicity. The low susceptibility of these tumor cells was confirmed in third-party cold inhibition assays in which they interfered minimally with killing of K562 targets under conditions in which unlabeled K562 cells efficiently blocked cytotoxicity. Cells prepared from normal lung tissue and Raji cells also failed to inhibit killing. Although in comparison to the K562 cell line freshly isolated tumor cells were resistant, their susceptibility may not be so low as to be biologically irrelevant, inasmuch as boosting of natural killing activity by interferon induced levels of cytotoxicity against both types of target cell that were unattainable by unstimulated effectors. Interferon-boosted killers were lytic for "normal" lung cells and the Raji cell line.     

Isolation and characterization of cytotoxic granules from human lymphokine (interleukin 2) activated killer cells

Cytotoxic granules were isolated from human lymphokine-activated killer (LAK) cells and analyzed for their biochemical properties. Isolated granules of approximately 85-95% purity were obtained by differential centrifugation followed by discontinuous Percoll gradient centrifugation. The murine lymphocyte granule marker N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase as well as cytotoxic activity toward the human tumor cell lines K562, Raji, Daudi, and CEM were associated with LAK granule fractions. Granule-associated N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase activity increased in recombinant interleukin 2 expanded human LAK cells in parallel with cytotoxic activity for Raji tumor cell targets. Cytotoxic LAK cell granules mediated calcium-dependent killing of the tumor cell lines K562, Raji, Daudi, and CEM. However, no calcium-dependent hemolytic activity was found. Preincubation of human granules with calcium, a treatment which totally inactivates the hemolytic and cytotoxic activity of murine lymphocyte granules [perforin 1 (P1)] had no effect on human LAK granule cytotoxicity for nucleated cells. Human LAK granules appear to contain P1 detected as cross-reactive antigen detected by mouse anti-P1 and human anti-C9 in Western blot analysis. In addition, Northern blot analysis of polyadenylated RNA isolated from human LAK cells using a murine P1 complementary DNA probe showed a cross-hybridizing 2.8- to 3.0-kilobase mRNA species identical in size to murine P1 mRNA. These results demonstrate that despite similar biochemical composition, functional differences exist between human and murine cytotoxic granules. Human LAK granules were synthesized in response to recombinant interleukin 2 activation and appeared in parallel with cytotoxicity for tumor targets, suggesting an important role for LAK granules in tumor cell cytotoxicity by human LAK cells.     

Cisplatin induces fas expression in esophageal cancer cell lines and enhanced cytotoxicity in combination with LAK cells

OBJECTIVE: To establish a new therapeutic approach for the treatment of esophageal cancer, we investigated an alternative mechanism of immunotherapy for sensitizing target cells to effector cells. METHODS: Six human esophageal cancer cell lines were used. The expression of Fas antigen on tumor cells was determined by flow cytometry. The cytotoxic effect of cis-dichlorodiammineplatinum (CDDP) and anti-Fas antibody was evaluated using an MTT assay. The cytotoxic activity of LAK cells was measured by a (51)Cr release assay. RESULTS: Five out of six esophageal cancer cell lines expressed Fas antigen at various levels (26.2-61.5%), and Fas expression increased after CDDP treatment. The antitumor effect of anti-Fas antibody on the esophageal cancer cell line and the antitumor effect of LAK cells activated by IL-2 were enhanced by pretreatment with CDDP. After concanamycin A treatment to specifically evaluate Fas-dependent cytotoxicity, LAK cells expressing Fas ligand killed only Fas-positive cells, but not Fas-negative cells. An anti-Fas neutralizing antibody inhibited this cytotoxicity. DNA fragmentation was shown in a cell line that was treated with CDDP and anti-Fas antibody, and also in the targeted esophageal cancer cell line cocultured with LAK cells. CONCLUSION: Our results suggest a potential clinical application of CDDP as a Fas inducer to make esophageal tumors susceptible to Fas antigen and LAK cytotoxicity.     

Lymphokine-activated killer (LAK) cells discriminate between Epstein-Barr virus (EBV)-positive Burkitt's lymphoma cells

We have generated in vitro lymphokine-activated killer (LAK) cells from healthy donors by stimulating their mononuclear leukocytes with recombinant interleukin-2 (rIL-2) (100 U/ml). After 6 days in culture, the lytic properties of the LAK cells were analyzed in the 51Cr-release assay by utilizing a target panel of 6 paired lines consisting of an Epstein-Barr virus (EBV)-positive Burkitt's lymphoma (BL) cell line and an EBV-transformed lymphoblastoid cell line (LCL) from the same donor, the Raji BL line and the natural killer (NK) cell-sensitive K562 line. The patterns of lysis showed that the LAK cells discriminated between two categories of BL cell lines. Group I/II BL tumor cells which expressed the common acute lymphoblastic leukemia antigen (CALLA), the BL-associated glycolipid antigen (BLA) and phenotypically resembled biopsy cells were strongly lysed whereas group III BL cells which had assumed an LCL-like phenotype during culture and lacked the CALLA and BLA surface markers were only poorly lysed. The LCL targets were generally resistant to lysis but the K562 cell line was particularly sensitive. The outcome of cell depletion and monoclonal antibody (MAb) studies indicated that the LAK cell populations were phenotypically and functionally heterogeneous and consisted of at least 2 subpopulations of effector cells; a tumor-specific component and an NK-cell-mediated component.     

AZT对肝癌细胞端粒酶活性及相关蛋白表达的影响

背景与目的：端粒酶抑制剂抑制端粒酶活性的机制十分复杂,可能涉及多个蛋白的共同作用。本研究通过3’-叠氮脱氧胸苷（3’-azido-deoxythymidine,AZT）作用于人肝癌细胞SMMC-7721。比较AZT作用后癌细胞端粒酶活性及相关蛋白的变化,探讨AZT抑制端粒酶活性的可能机制。方法：利用噻唑蓝[3（4,5-demethyhhiazole-2-y1）-2,5-diphenyl tetrazolium-bromide,MTT]实验确定AZT作用的最佳作用时间和浓度;实时荧光定量端粒重复序列扩增法（real-time fluorescent quantitative TRAP assay,FQ-TRAP法）检测AZT作用后,SMMC-7721细胞端粒酶活性变化;用缺口末端标记技术（terminal deoxyribonucleotidyl transferse（TdT）-mediated biotin-16-dUTP nick-end labelling,TUNEL）法和流式细胞术检测AZT作用后．SMMC-7721细胞凋亡情况;单细胞激光拉曼光谱技术和蛋白质芯片-飞行时间质谱仪,检测AZT作用后特异蛋白质的变化。结果：AZT抑制癌细胞生长的最佳作用时间为48h,最佳作用浓度为20mmol／L;FQ-TRAP法检测发现,AZT作用后肝癌细胞端粒酶活性与对照组相比受到明显抑制（P=0．0001）;TUNEL法观察到AZT诱导肝癌细胞凋亡形态学改变．流式细胞术检测AZT诱导肝癌细胞凋亡率为13．5％：单细胞激光拉曼光谱技术观察到,AZT作用后有7个与蛋白代谢相关的特征峰变化;蛋白质芯片．飞行时间质谱仪检测发现,AZT作用后有24个蛋白分子在癌细胞中高表达,8个蛋白分子在癌细胞中低表达,32个差异蛋白均属于小分子蛋白。结论：AZT可抑制SMMC-7721细胞端粒酶活性,诱导凋亡与相关特异小分子蛋白有关。     

In vitro and in vivo susceptibility of human leukemic cells to lymphokine activated killer activity

The susceptibility of human myeloid and lymphoid leukemic blasts to the lytic action of recombinant interleukin-2 (rIL-2)-generated lymphokine activated killer (LAK) cells was analyzed. With the exception of the K562 cell line, all 9 leukemic cell lines tested were resistant to the natural killer activity of freshly isolated peripheral blood lymphocytes (PBL) from healthy donors but were susceptible to the lytic action of PBL cultured for 3 days in the presence of rIL-2. Of the 32 primary myeloid and lymphoid acute leukemia samples investigated, the great majority were natural killer cell-resistant but were variably sensitive to LAK effectors. Variations in LAK activity were observed according to the donor of PBL, while little or no difference was documented in the capacity to elicit LAK activity of PBL cultured with 100 or 1,000 U of rIL-2/ml. Pretreatment of the leukemic target cells with neuraminidase did not increase substantially their sensitivity to LAK activity. LAK cells generated from the PBL of patients at the onset of the disease or in complete clinicohematological remission lysed Raji cells as efficiently as normal LAK effectors. Finally, LAK cells were capable of abrogating the tumor growth in nude mice of a human leukemic T cell line. These findings demonstrate the susceptibility in vitro and in vivo of human leukemic blasts to the lytic effect of LAK cells and point to a possible clinical exploitment of this new form of adoptive immunotherapy in the management of acute leukemia.     

CD80 transfected human hepatocellular carcinoma cells activate cytotoxic T lymphocytes to target HCC cells with shared tumor antigens

Human HCC cell lines (BEL-7402, SMMC-7721 and QGY-7703) do not express CD80 molecules, although they express MHC class I molecules and ICAM-1. HCC's poor immunogenicity may therefore be due to lack of CD80 molecules. This study first investigated whether CD80 molecules could provide minimal co-stimulatory signal for establishing an efficient anti-tumor immunity in HCC and second, whether the transfection of CD80 into the BEL-7402 cell line could induce T cell activation for targeting other HCC cell lines expressing shared common antigens. The transfection of cDNA encoding CD80 into ICAM-1+ HCC BEL-7402 cells was confirmed by flow cytometrical analysis. The CD80-transfected cells could enhance the immunogenicity of BEL-7402 cells as detected by T cell proliferation assay, and also activated the T cells at a higher proliferation rate comparing with the BEL-7402 cells transfected with vector only. The CD80-transfected cell line was also found able to activate T cells which subsequently induced cell lysis of SMMC-7721, QGY-7703 and parent BEL-7402 cell lines as detected by cytotoxicity assay. It can be concluded that the cytotoxicity was due to MHC class I restricted CD8+ cytotoxic T lymphocytes, but not natural killer (NK) cells, since this cytotoxic effect could be blocked by anti-MHC class I antibody and the cytotoxicity was shown very low in NK-cell-sensitive K562 cell line. Electroporation of CD80 cDNA into human HCC cells could increase the expression of the functional CD80 molecules and enhance the immunogenicity of the genetically-modified HCC cells to activate T cells for targeting 3 HCC cell lines in an HLA-restricted manner.     

Inhibition of Colony Formation of Drug-resistant Human Tumor Cell Lines by Combinations of Interleukin-2-activated Killer Cells and Antitumor Drugs

The cytotoxicity of interleukin-2-activated killer (LAK) cells with or without anticancer drugs against cell lines with acquired drug resistance was evaluated in vitro by colony assay. Human non-small cell lung cancer cell lines, PC-9 and PC-14, human leukemia cell line, K-562, and their sublines resistant to cisplatin (CDDP), PC-9/CDDP and PC-14/CDDP, and to adriamycin (ADM), K-562/ADM, were used as target cells. PC-9/CDDP demonstrated a marked increase in susceptibility to killing by both peripheral blood lymphocytes (PBL) and LAK cells, as compared to the parental cell line, PC-9. The cytotoxicity of PBL and LAK cells against PC-14/CDDP and K-562/ADM was similar to that against their parental cell lines. Moreover, the combination of LAK and CDDP had a synergistic effect on PC-14 and PC-14/CDDP.