免疫球蛋白样抑制性受体KIR基因与HLA-Cw的匹配对NK细胞活性的影响

Gene Kir in Match with HLA-Cw Impacts on NK Cell Cytotoxicity

本研究探索自然杀伤(natural killer,NK)细胞表面杀伤细胞免疫球蛋白样抑制性受体(killer immunoglob-ulin-like inhibition receptor,KIR)基因与HLA-Cw配体匹配对NK细胞活性的影响。对27名健康人取新鲜外周血20ml,用NK细胞免疫磁珠分选试剂盒负向分选高纯度NK细胞。对30例初治确诊急性髓系白血病(AML)患者取新鲜骨髓液10ml,分离单个核细胞作为靶细胞。流式细胞仪检测NK细胞CD158a,CD158b表达水平。取健康人和患者的外周血各2ml,以PROTRANS法抽提DNA,采用序列特异性引物PCR-SSP分型技术分别检测HLA-Cw、KIR基因。MTT法检测KIR与HLA-Cw基因不同组合的NK细胞对AML患者白血病细胞的杀伤率。结果表明:分选后的NK细胞,纯度为(90.8±6.08)%。NK细胞KIR基因与靶细胞HLA-Cw等位基因的匹配数少则NK细胞的杀伤效应强,0个等位基因匹配的杀伤率为(50.66±8.40)%,1个匹配与2个匹配的杀伤率分别为(38.28±6.71)%,(19.74±4.15)%,(F=20.226,p<0.001)。NK细胞的KIR表达水平与杀伤作用也有一定的联系(F=16.276,p值<0.001)。结论:NK细胞对AML白血病细胞的杀伤作用与抑制性KIR/HLA-Cw的匹配数及KIR的表达相关,匹配越少、KIR表达越低,杀伤率越高。

The aim of this study was to investigate how the killer immuneglobulin-like inhibition receptor （KIR） in match with HLA-Cw impacts on NK cell activity. Mononuclear cells were isolated in 20 ml peripheral blood from 27 healthy persons by Ficoll-Hypaque and purified by NK cell isolation kit. Target cells were mononuclear cells isolated from bone marrow of 30 de novo AML patients. The KIR expression were detected by flow cytometry with antibodies against CD158a, CD158b. The 2 ml of peripheral blood from healthy persons and AML patients were collected, the DNA was extracted by using PROTRANS method, the HLA-Cw and KIR gene were detected by PCR-SSP typing with sequence specific primers. The NK cell cytotoxicity against AML cells was determined by MTT after combination of KIR with HLA-Cw gene. The results indicated that the purity of NK cells was （ 90.8 ± 6.08 ） %. The less the KIR/HLA-Cw matched, the more activity was shown in NK cells. When no match of NK cell/target cell （KIR/HLA-Cw） there was, the cytotoxicity was （ 50.66 ± 8.40 ） %, 1 or 2 matches showed cytotoxicity of （ 38.28 ± 6.71 ） % and （ 19.74 ± 4.15 ）% （p 〈 0.001 ）. Expression level of KIRs on NK cells also was related with cytotoxicity level （p 〈 0.001 ）. It is concluded that the interaction between inhibitory KIR and HLA ligands, and also expression level of KIRs on NK cells both impact significantly on NK cell function, that the less match of KIR/HLA-Cw, and the less expression of KIRs on NK cells result in the stronger NK cell cytotoxicity.