干扰素-α1b增强人γδT细胞对Daudi细胞系的细胞毒活性及相关机制

目的探讨干扰素-α1b(IFN-α1b)对人γδT细胞体外杀伤肿瘤细胞的促进作用及其相关机制。方法用IFN-α1b预处理的Daudi细胞作为靶细胞;用IFN-α1b预处理的γδT细胞作为效应细胞;LDH法检测γδT细胞对Daudi细胞的细胞毒活性;ELISA检测效靶细胞混合上清中γδT细胞分泌的颗粒酶B和γ干扰素水平;流式细胞计量技术检测IFN-α1b预处理Daudi细胞表面Fas受体和应激蛋白配体ULBP3/ULBP4的表达,以及γδT细胞表面活化分子CD69和CD25的变化。结果IFN-α1b分别预处理Daudi细胞和γδT细胞都能显著增强γδT细胞对Daudi细胞的细胞毒活性(P<0.0001);IFN-α1b预处理的γδT细胞分泌颗粒酶B和γ干扰素的能力显著提高(P<0.05);IFN-α1b能上调Daudi细胞表面Fas受体和应激配体ULBP4的表达水平,而应激配体ULBP3的表达没有变化;IFN-α1b还能上调γδT细胞表面CD69的表达水平,而CD25的表达没有变化。结论IFN-α1b能通过不同的途径促进人γδT细胞对肿瘤细胞系Daudi细胞的体外细胞毒活性,两者的联用能增强γδT细胞的肿瘤治疗疗效。     

肿瘤特异性TCRαβ基因转染诱导记忆性T细胞分化及其免疫功能的研究

目的研究特异性TCR基因转染T细胞被肿瘤抗原激活后,记忆性T细胞的分化情况,并明确其表型特征和免疫功能。方法密度梯度离心法分离PBMC,重组TCR腺病毒感染T细胞,流式细胞术检测外源TCR表达效率。AFP表位肽刺激T细胞,流式细胞术检测TCR基因转染T细胞经抗原刺激后,记忆性T细胞标志分子表达。MTT法检测T细胞对不同肿瘤细胞株的杀伤活性。Annexin V-PI双染法检测靶细胞凋亡比例。ELISA法检测T细胞作用于靶细胞后IFN-γ与IL-2分泌水平。结果重组腺病毒载体感染3 d后,外源TCR表达比例接近30%。特异性TCR基因转染可有效促进T细胞识别肿瘤抗原后活化,CD45RO+细胞比例逐渐上升至接近50%。CD45RO+细胞以CD62L–CD44+表型为主。此后CD62L+细胞比例逐渐上升。最终出现分群明显的CD62L+CD44+TCM表型细胞。特异性TCR基因转染能够促进T细胞杀伤AFP+靶细胞,诱导靶细胞凋亡,并促进IFN-γ分泌。抗原预先刺激能够进一步增强TCR基因转染T细胞抗肿瘤免疫效应。结论 TCR基因转染能够有效促进T细胞识别肿瘤抗原后活化。经肿瘤抗原预先刺激的TCR基因转染T细胞将启动记忆性T细胞分化,在再次遭遇表达相同抗原的肿瘤细胞时发挥更为强烈的免疫效应。     

B7-H1阻断对CD3AK细胞体外生物学活性的影响

目的: 探讨B7-H1阻断对CD3AK细胞增殖活化及其抗肿瘤免疫效应的影响.方法: 利用CD3单克隆抗体(mAb)刺激健康人外周血淋巴细胞诱导产生CD3AK细胞,然后利用B7-H1阻断型抗体阻断B7-H1通路,3H-TdR渗入法检测阻断后CD3AK细胞的增殖能力,ELISA法检测阻断后CD3AK细胞分泌IFN-γ、 TNF-α和IL-10的水平,同时将CD3AK细胞作用于膀胱肿瘤BIU-87细胞,MTT法检测阻断后CD3AK细胞的杀伤活性.结果: B7-H1阻断后,CD3AK细胞的增殖能力明显增强,体外存活时间明显延长;其分泌IFN-γ、 TNF-α的水平明显提高,而分泌IL-10的水平明显下降;同时CD3AK细胞对BIU-87细胞的杀伤活性亦明显升高.结论: 阻断B7-H1通路可以促进和维持CD3AK细胞的增殖和活化,并增强其抗肿瘤的免疫效应.阻断B7-H1通路将有望成为肿瘤免疫治疗的新策略.     

抗人P185erbB2 scFv-Fc-IL-2增强LAK样和ADCC杀伤作用及机制的实验研究

目的 将抗人P185erbB2 scFv-Fc-IL-2融合蛋白(HFI)分别作用于表达高、中、低3个水平erbB2受体的SKOV3、MCF-7、SGC-7901三株肿瘤细胞和健康人外周血单个核细胞(PBMC),探讨HFI调变肿瘤细胞表面分子,激活免疫效应细胞的机制;模拟体内肿瘤组织,将HFI-PBMC-肿瘤细胞混合培养,探讨HFI对分别表达高、中、低3个水平erbB2肿瘤细胞的淋巴因子激活的杀伤细胞(LAK)样和抗体依赖性细胞介导的细胞毒(ADCC)作用,为临床应用提供实验依据.方法 MTF法检测细胞增殖、杀伤活性;流式细胞术检测细胞表面分子的表达变化;应用非核素细胞毒试剂盒观察HFI介导ADCC杀伤作用.结果 HFI处理后SKOV3细胞表面杀伤相关分子细胞间黏附分子-1(ICAM-1)、Fas表达水平分别由24.85%、0.53%增高到85.36%、59.19%;SKOV3、MCF-7、SGC-7901三株肿瘤细胞erbB2表达水平分别由98.48%、42.60%、36.66%下降到94.01%、30.95%、12.36%.HFI刺激后人PBMC的增殖活性显著增强,呈时间依赖效应,CD3+ CD8+ T细胞和CD3- CD16+ CD56+NK细胞分别由24.37%、6.90%提高到38.80%、13.45%,CD25、淋巴细胞功能抗原-1(LFA-1)、FasL表达水平分别由3.99%、86.52%、5.02%提高到12.96%、99.06%、16.19%.HFI活化的人PBMC对不同erbB2表达水平肿瘤细胞的LAK样杀伤活性,在各效靶比均比对照组明显提高.HFI能够介导和增强人PBMC对表达erbB2肿瘤细胞的ADCC杀伤作用.结论 HFI上调SKOV3细胞表面杀伤相关分子ICAM-1、Fas表达,下调肿瘤细胞表面erbB2表达.HFI对人PBMC具有明显的激活增殖作用,活化的人PBMC对表达不同水平erbB2肿瘤细胞的LAK样杀伤作用均显著增强.HFI能够介导和增强人PBMC对肿瘤细胞的ADCC杀伤作用,且杀伤活性的高低与肿瘤细胞表面erbB2表达水平的高低呈平行关系.     

细胞因子诱导HepG2细胞ICAM—1表达的研究

目的 研究IFN-γ、TNF-a和IL-1对HepG2细胞细胞间粘附分子-1（ICAM-1）表达的影响。方法 用IFN-γ、TNF-a和IL-1在体外诱导HepG2细胞表达ICAM-1,并用细胞FLISA检测HepG2细胞ICAM-1表达水平。结果 未经刺激的HepG2细胞ICAM-1表达水平很低。TNF-a、IL-1、IFN-γ刺激后,HepG2细胞ICAM-1表达均明显增强,其表达水平与细胞因子浓度呈一定的剂量依赖关系;随着细胞因子刺激时间的延长,HepG2细胞ICAM-1表达也逐渐增多。结论IFN-γ、TNF-a和IL-1等细胞因子能诱导体外培养HepG2细胞ICAM-1增强表达。     

干扰素-γ诱导大鼠肠黏膜微血管内皮细胞表达细胞黏附因子-1和干扰素-γ受体α

目的 以体外培养的大鼠肠黏膜微血管内皮细胞(RIMMVECs)为研究对象,探讨干扰素-γ(IFN-γ)对于体外培养的RIMMVECs表达细胞黏附因子-1(ICAM-1)和IFN-γ受体α(IFN-γRα)的影响.方法 体外分离培养RIMMVECs,用不同浓度的IFN-γ对所培养的RIMMVECs进行诱导,通过荧光定量RT-PCR法和流式细胞术,从mRNA和蛋白水平检测活化后的RIMMVECs表达ICAM-1和IFN-γRα的情况.结果 浓度为20 μg/L和40 μg/L的 IFN-γ可以激活RIMMVECs,在mRNA和蛋白水平均能提高ICAM-1的表达,并且6 h时达到高峰;20 μg/L的IFN-γ刺激RIMMVECs后,可使其上调表达IFN-γRα mRNA,但是蛋白表达量却随着刺激时间逐渐降低;而40 μg/L的IFN-γ刺激RIMMVECs 2 h后,IFN-γRα mRNA 达到峰值,6 h之后,其表达量呈下降趋势,IFN-γRα蛋白浓度也随之逐渐降低;10 μg/L的IFN-γ对于ICAM-1和IFN-γRα的表达无影响.结论 IFN-γ可能是通过影响微血管内皮细胞(MVECs)表面IFN-γRα分子和ICAM-1的表达,从而调控和参与细胞免疫反应和炎症反应.     

单链双特异性抗体(BHL-I)介导的细胞毒作用及其可能机制研究

目的：观察单链双特异性抗体（BHL-I）介导的PBL对靶细胞SKOV3的杀伤作用，并研究其细胞毒作用的可能机制。方法：MTT法检测在不同效靶比、不同作用时间、不同靶细胞（SKOV3、BEL-7402）、不同BHL-I浓度等条件下，BHL-I介导PBL对靶细胞的杀伤作用；RT-PCR检测杀伤过程中PBL的穿孔素（Perforin）、颗粒酶（GranzymeB）mRNA的表达及细胞培养上清液中TNF-α、IFN-γ含量变化。结果：BHL-I介导的PBL对SKOV3细胞毒作用明显高于对BEL-7402的，并且在效靶比10∶1、作用36小时、BHL-I浓度为25μg/ml时，PBL对靶细胞SKOV3的细胞毒作用最为显著；在IL-2存在下，BHL-I可引起Perforin、GranzymeB mRNA较高表达及细胞培养上清液中TNF-α、IFN-γ含量升高，当作用时间为72小时时，这些细胞因子的表达有所下降。结论：BHL-I能介导PBL对表达有相应靶抗原的SKOV3细胞具有高效杀伤作用，其细胞毒作用可能与效应细胞表达Perforin、GranzymeB、TNF-α、IFN-γ等有关。     

IFN-α磷酸化STAT1和STAT4诱导人NK细胞产生IFN-γ并增强其杀伤活性

目的研究IFN-α对CD56+NK细胞的细胞因子分泌、杀伤功能和细胞内信号传导的作用。方法分离健康人PBMC分别与培养液、IFN-α和IL-12培养,利用酶联免疫吸附法(ELISA)检测培养上清中IFN-γ的水平。同时采用流式细胞仪在单个细胞水平上分析IFN-α诱导IFN-γ产生的细胞亚群以及该细胞亚群对肿瘤细胞的杀伤作用和信号传导机制。结果经IFN-α刺激后,PBMC能产生低剂量的IFN-γ。细胞亚群分析的结果表明,IFN-α诱导CD56+NK细胞产生IFN-γ,但对CD4+T和CD8+T细胞无明显作用。IFN-α促进NK细胞的杀伤功能。促进STAT1和STAT4磷酸化。结论 IFN-α通过磷酸化STAT1和STAT4,增加NK细胞IFN-γ分泌和增强杀伤功能。     

CD40配基化调节小鼠树突状细胞上B7-H3分子表达的研究

目的 探讨CD40配基化对小鼠骨髓来源树突状细胞上B7-H3分子表达的调节作用及其生物学意义。方法 采用GM-CSF和IL-4联合方案体外诱导小鼠髓系DC，并利用mCD40-CHO和TNF-α分别刺激凋亡肿瘤细胞负载的Dc制备成熟DC；采用间接免疫荧光标记法检测成熟Dc上B7-H3分子的表达；RT-PCR检测B7-H3 mRNA转录水平；混合淋巴细胞反应（MLR）和B7-H3单抗阻断实验分析CD40配基化的DC表面B7-H3分子在T细胞活化中的作用；^3H-TdR掺入试验检测DC对T淋巴细胞的促增殖效应；ELISA测定各组MLR反应和DC培养上清中IFN-γ分泌水平。结果 B7-H3分子在DC不同分化发育阶段均有表达，CD40配基化能显著上调凋亡肿瘤细胞负载的DC中B7-H3表达，TNF-α激发的DC弱表达（P〈0．05）；阻断CD40配基化的DC上B7-H3分子能抑制T细胞增殖和IFN-γ分泌；CD40配基化促进凋亡肿瘤细胞负载的DC分泌IFN-γ量也明显高于TNF-α组（P〈0．05）。结论 体外CD0配基化DC的B7-H3分子上调性表达有助于其刺激T细胞增殖和IFN-γ的产生。     

15d-PGJ2对肾小管上皮细胞CD40及RANTES表达的影响

目的：观察过氧化物酶体增殖物激活受体γ（PPARγ）激动剂15d-PGJ2对干扰素-γ（IFN-γ）和肿瘤坏死因子α（TNF-α）诱导的人近端肾小管上皮细胞（HK-2）CD40和RANTES表达的影响。方法：体外培养人近端肾小管上皮细胞株，分组如下：（1）正常对照组；（2）IFN-γ（50μg／ml）组；（3）TNF-α（10ng／ml）组；（4）IFN-γ（50μg/ml）＋TNF—α（10ng／ml）组；（5）IFN-γ（50μg／ml）＋TNF-α（10ng／ml）分别加1、3、5μmol／L15d-PGJ2组；（6）IFN-γ＋TNF-α．刺激＋15d-PGJ2（5μmol／L）＋GW9662（PPARγ特异拮抗剂）1μmol／L组。GW9662和15d-PGJ2分别在IFN-γ和TNF-α刺激前3和2小时加入。分别采用RT-PCR、流式细胞仪（FACS）和酶联免疫法（ELISA）检测CD40和RANTES基因和蛋白的表达水平。结果：正常HK-2细胞中，CD40、RANTES有基础水平表达。IFN-γ能显著上调HK-2细胞CD40蛋白的表达；TNF-α单独刺激对CD40表达无显著影响，但能增强IFN-γ的刺激效应。IFN-γ＋TNF-α显著增加HK-2细胞RANTES的表达和分泌。15d—PGJ2呈剂量依赖式在基因和蛋白水平显著抑制IFN-γ＋TNF-α．诱导的CIMO和RANTES的表达。加入PPARγ特异拈抗剂GW9662后，能够部分逆转15d-PGJ，对CIMO和RANTES表达的抑制效应，但并不能完全阻断其作用。结论：15d-PGJ2部分通过PPARγ介导的信号途径参与抑制IFN-γ＋TNF-α．诱导的人近端肾小管上皮细胞CD40和RANTES的表达，从而在肾脏局部发挥免疫调节和抗炎作用。     

Lymphocyte leukocyte function-associated antigen 1 interacting with target cell intercellular adhesion molecule 1 co-activates cytolysis triggered via CD16 or the receptor involved in major histocompatibility antigen-unrestricted lysis

The binding of leukocyte function-associated antigen 1 (LFA-1)(CD11a/CD18) to its natural target ligand, intercellular adhesionmolecule 1 (ICAM-1) (CD54), is an important step in lymphocyteadhesion to cells and its subsequent activation. We studiedwhether LFA-1 – ICAM-1 interactions affect tumor cellsuceptibility to MHC-unrestricted lysis by TCR–CD3–CD16⁺natural killer (NK) and TCR⁺CD3⁺CD16^+/– lymphocytes. Moreover,tumor target cell susceptibility to anti-CD16 mAb-triggeredlysis by TCR- NK cells was investigated. Therefore, ICAM-1⁺or ICAM-1^– tumor cell lines were used as target cells.Two melanoma-derived cell lines expressing little or no ICAM-1were relatively resistant to MHC-unrestricted lysis as wellas anti-CD16 mAb-triggered lysis by fresh or cloned TCR^–NK cells. The ICAM-1^– melanoma cell line was also relativelyresistant to MHC-unrestricted lysis by TCR^+/+ clones. Tumornecrosis factor (TNF) induced ICAM-1 expression on ICAM-1^–tumor cells, and simultaneously increased target cell susceptibilityto MHC-unrestricted as well as to anti-CD16 mAb-triggered lysis.This enhanced level of lysis was inhibited by anti-ICAM-1 mAb.Our data demonstrate that LFA-1–ICAM-1 interactions increaseMHC-unrestricted or CD16-mediated cytolysis of tumor cells.Anti-CD18 (LFA-1ß) mAb inhibited MHC-unrestrictedlysis of ICAM-1⁺ and ICAM-1^– tumor cells. However, anti-CD18mAb only blocked formation of lymphocyte–target cell conjugateswith ICAM-1⁺ but not with ICAM-1^– target cells. Theseresults suggest that LFA-1 can mediate positive as well as negativesignals. Our data also show that LFA-1–ICAM-1 interactionsco-activate and regulate cytotoxicity triggered via the receptorstructure(s) involved in MHC-unrestricted lysis as well as viaCD16.     

LFA-3 co-stimulates cytokine secretion by cytotoxic T lymphocytes by providing a TCR-independent activation signal

T cell activation is known to depend not only on efficient antigen recognition and subsequent signaling through TCR, but also on interactions involving multiple adhesion and accessory molecules such as CD28/B7, LFA-1/ICAM-1 and LFA-3/CD2. The present study dissects the role of LFA-3/CD2 interactions in the activation of melanoma-specific CD8⁺ T cell clones. To this end we analyzed the influence of LFA-3 density on melanoma cells on lysis and cytokine production (TNF, IL-2, IFN-γ) by T cells following activation by various amounts of antigenic peptides. Our results indicate that increasing LFA-3 density on melanoma cells variably affects their lysis susceptibility, but systematically and considerably enhances cytokine production by melanoma-specific cytotoxic T lymphocyte (CTL) clones. At any stimulatory antigen density, LFA-3 increased the fraction of responding cells and/or cytokine amounts produced by individual cells, without affecting TCR down-regulation. These results show that CD2 engagement increases cytokine gene activation essentially by providing to T cells a TCR-independent co-activation signal. From a practical point of view, our data demonstrate that the level of LFA-3 expressed on tumors critically affects cytokine production by specific CTL and thus the efficiency of specific immune reactions mediated by these cells.     

Modulation of intercellular adhesion molecule 1 (ICAM-1) expression on the human mast-cell line (HMC)-1 by inflammatory mediators

The effect of inflammatory mediators on the expression of several surface adhesion molecules on the human mast-cell line (HMC)-1 was studied. By flow cytometry, it could be shown that among several surface adhesion molecules (ICAM-UCDS4, VLA-4/CD49d, Mac-UCD11b, LFA-1/CD11a, LFA-2/CD2, LFA-3/CDS8, VCAM-1), only the constitutively expressed immunoglobulin family member intercellular adhesion molecule-1 (ICAM-1) is modulated by proinflammatory cytokines on HMC-1 mast cells. Stimulation with tumor necrosis factor-a (TNF-α) and interferon-γ (IFN-γ) resulted, in addition to interleukin-(lL-)4, in selective upregulation of ICAM-1 expression. Costimulation of either IL-4 or IFN-γ with TNF-α further increased the ICAM-1 expression as compared to the stimuli alone. In contrast, stem-cell factor (SCF), granulocyte/macrophage colonystimulating factor (GM-CSF), IL-10, IL-8, monocyte chemotactic and activating factor (MCAF), and the complement split product C5a failed to modulate the expression of any adhesion molecule examined. The levels of cytoplasmic free calcium in HMC-1 mast cells were not altered by cross-linking surface ICAM-1, suggesting linkage of other intracellular signaling pathways. This cytokine-induced upregulation of ICAM-1 expression might reveal a putative regulatory mechanism of mast-cell interaction with effector cells bearing the counterparts of ICAM-1 (CD54), the molecules Mac-1 (CD11b/CD18) and leukosialin (CD43), and the principal ligand LFA-1 (CD11a/CD18).     

Lymphokine-Activated Killer (LAK)-Mediated Lysis of Sequentially Isolated Ovarian Cancer Cell Lines

PROBLEM: Understanding immunologic eradication of cancer is hampered by failure to explore tumor evolution. Cell surface molecules may alter with therapy and disease progression. These alterations can translate into variable susceptibility to immune-mediated cell lysis. METHOD OF STUDY: Cell lines from a patient with ovarian carcinoma isolated at surgical debulking (UL-3A), during chemotherapy (UL-3B), and after progression (UL-3C) were used to study changes in cell lysis by natural killer (NK) and lymphokine-activated killer (LAK) cells. The role of adhesion molecules ICAM-1, LFA-3, and glycoproteins in the demonstrated differential killing was also examined. RESULTS: An inverse relationship between attachment and lysis was demonstrated. UL-3C, the most sensitive to lysis (50%), attached the least lymphocytes (40%), whereas UL-3A, the least sensitive (33%), attached the most lymphocytes (71%). A correlation with ICAM-1 and LFA-3 expression was not demonstrated. CONCLUSION: Ovarian cancer cells evolve throughout the disease course, and this may manifest as differential sensitivity to immune-mediated cell lysis.     

Heterogeneous susceptibility of human melanoma clones to monocyte cytotoxicity: role of ICAM-1 defined by antibody blocking and gene transfer.

Five clones derived from the same human malignant melanoma lesion were studied for their susceptibility to killing by human monocytes activated by exposure to interferon (IFN)-gamma and lipopolysaccharide. Melanoma clones were heterogeneous in their susceptibility to human monocyte cytotoxicity, with one clone (2/21) exhibiting extremely low levels of lysis. The different levels of susceptibility to monocyte cytotoxicity were not accounted for by susceptibility or resistance to monokines [tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6] because: (a) these effector molecules had little (TNF) or no (IL-1 and IL-6) cytolytic activity under these conditions; and (b) anti-TNF antibodies had marginal effects on cytotoxicity. Monocytes bound less to resistant than to susceptible melanoma cells. Monocyte-resistant 2/21 melanoma cells expressed substantially lower levels of ICAM-1 and VLA-4 than susceptible cells. Anti-CD18 and, to a lesser extent, anti-ICAM-1 mAb inhibited binding and cytotoxicity of human monocytes on malignant melanoma whereas anti-VLA-4 had no inhibitory action. Transfection of the ICAM-1 gene under the control of a constitutive promotor resulted in high levels of expression of ICAM-1 in 2/21 melanoma cells and, concomitantly, in augmented susceptibility to activated monocyte cytotoxicity. The augmented killing of ICAM-1 transfected 2/21 cells was inhibited by anti-ICAM-1 mAb. These results demonstrate that the CD18-ICAM-1 adhesion pathway can play an important role in the expression of human monocyte cytotoxicity on melanoma target cells and that heterogeneity in expression of ICAM-1 can underlie differences in susceptibility to tumoricidal activity.     

Reduced antigen-presenting function of human Epstein-Barr virus (EBV)-B cells and monocytes after UVB radiation is accompanied by decreased expression of B7, intercellular adhesion molecule-1 (ICAM-1) and LFA-3.

In this study, the effect of ultraviolet-B (UVB) radiation on antigen-presenting function was studied, to investigate whether antigen-presenting cells (APC) are inhibited by UVB through a common mechanism. Two types of human APC were used: EBV-B cells and monocytes, and these were irradiated in vitro with single low doses of UVB (range 0-200 J/m2). Irradiation of EBV-B cells or monocytes resulted in similar dose-dependent reduction in APC function, when determined by the allogeneic mixed leucocyte reaction (MLR) or Candida albicans- or tetanus toxoid-specific T cell response. Our study shows that the reduced APC function was not likely to be caused by alterations in antigen processing or cytokine production. However, UVB-irradiated APC displayed marked changes in adhesion molecule expression. Irradiated EBV-B cells showed reduced expression of ICAM-1 (30%), LFA-3 (25%) and B7-1 (35%), while expression of HLA-DR, CD19 and LFA-1 was not affected. UVB irradiation of monocytes did result in reduction in the expression of HLA-DR (30%), LFA-3 (40%), ICAM-1 (65%) AND B7-1 and B7-3 (90%), but had no effect on CD14, LFA-1 and ICAM-3 expression. Addition of non-irradiated cells (but not the supernatant of these cells) or CD28 antibodies partly restored T cell activation, indicating that UVB-induced reduction in APC function is at least partly mediated via impairment of co-stimulatory molecule expression.     

Role of adhesion molecules in lymphokine-activated killer cell killing of bladder cancer cells: further evidence for a third ligand for leucocyte function-associated antigen-1.

The lysis of eight human bladder cancer cell lines by lymphokine-activated killer cells (LAK) was found to be partially dependent upon the expression by the target cell of either intercellular adhesion molecule-1 (ICAM-1) or intercellular adhesion molecule-2 (ICAM-2). Using adhesion blockade studies these molecules were found to contribute towards sensitivity to lysis. Tumour lines of low grade (G1) did not constitutively express ICAM-1, but were found to express ICAM-2. High grade cells (G2, G3), however, only constitutively expressed ICAM-1 on their cell surface. Interferon-gamma (IFN-gamma) induced and augmented the expression of ICAM-1 by all except one of the cell lines (UMUC3) in a dose- and time-dependent manner. This was accompanied by an increased susceptibility to lymphokine-activated killer mediated cytolysis. Anti-ICAM-1 antibodies partially inhibited the increase in cell lysis due to IFN-gamma. However, this inhibition was not complete. When effector cells were treated with antibodies to leucocyte function-associated antigen-1 (LFA-1) the inhibition of lysis was greater and ranged from 72 to 96% with a mean of 87% inhibition. These results suggest that the increased sensitivity of IFN-gamma-treated bladder cancer cell lines to LAK cells is partially attributable to the induction of ICAM-1. However, blocking of ICAM-1 with antibodies could only partially inhibit the increased LFA-1-dependent lysis. This supports recent evidence for the existence of an additional ligand for LFA-1, other than ICAM-1 and ICAM-2.     

Selective regulation of ICAM-1 and major histocompatibility complex class I and II molecule expression on epidermal Langerhans cells by some of the cytokines released by keratinocytes and T cells

Epidermal Langerhans cells (LC) are major histocompatibility complex (MHC) class II (Ia)-positive dendritic cells that act as potent antigen-presenting or accessory cells for primary and secondary T cell-dependent immune responses. Recent studies have disclosed that the morphological, functional, and phenotypic characteristics of LC are variably and drastically modulated by external stimuli both in vivo and in vitro. However, little is known of the biological significance of diverse cytokines in regulating the surface molecules of LC. To determine the regulatory properties of ICAM-1, Ia, and MHC class I (H-2K) molecules in LC, we have examined the effects of interleukin (IL)-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-10, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the expression of these molecules. Among the cytokines examined, IFN-γ markedly and reproducibly up-regulates the expression of H-2K, but not ICAM-1, in Ia⁺ LC in a time- and dose-dependent manner. TNF-α consistently up-regulates the expression of ICAM-1, but not H-2K, in a time- and dose-dependent manner. IL-10 slightly but reproducibly inhibits the expression of ICAM-1, but not H-2K, in a time- and dose-dependent manner. IL-10 potently inhibits the TNF-α-induced ICAM-1 up-regulation, but not the IFN-γ-induced H-2K up-regulation. Moreover, no cytokine consistently affects the Ia expression of LC. In addition, slight enhancing effects have been observed on H-2K expression by IL-4, and on ICAM-1 expression by IL-1α, IL-1β, or GM-CSF. The present data suggest that the selective regulation is operative in a certain cell surface moiety of LC by various cytokines. These results further facilitate our understanding of immunobiology of LC.