多价抗人精浆蛋白/抗CD3双特异性单链抗体的活性研究

目的探讨多价抗人精浆蛋白/抗CD3双特异性单链抗体的生物学活性.方法利用流式细胞仪和51Cr释放试验评价多价双特异性单链抗体的抗原亲和活性和体外介导杀伤靶细胞的效果.利用母性BALB/C裸鼠前列腺癌模型分析多价双特异性单链抗体在体内介导细胞毒T淋巴细胞对肿瘤细胞杀伤的能力.结果多价双特异性抗体可以特异性结合表达PSA的前列腺癌细胞和CD3阳性淋巴瘤细胞,阳性结合率分别为74%和83%.在体外,有细胞毒T淋巴细胞存在时多价抗体可引起前列腺癌细胞裂解.与对照组比较,接种前列腺癌细胞的裸鼠在注射激活的细胞毒T淋巴细胞的同时接受多价抗体治疗后,肿瘤生长明显受到抑制(P＜0.05).结论多价抗人精浆蛋白/抗CD3双特异性单链抗体具有良好的生物学活性,在体内外均可以介导细胞毒T淋巴细胞对靶细胞的杀伤.     

重组免疫毒素scFv-psm-ETA对人前列腺癌细胞生长抑制作用的研究

目的　探讨重组免疫毒素scFv psm ETA对人前列腺癌细胞生长的抑制作用。　方法制备具有良好器官特异性的免疫毒素scFv psm ETA,从抗前列腺特异膜抗原(PSM)单抗杂交瘤细胞中克隆抗PSM单抗重、轻链可变区基因,与切去细胞结合区的ETA基因相连,构建成表达scFv psm ETA的质粒pSW200 psm,转化E.coli株CC118,表达有生物活性的融合蛋白scFv psm ETA,经M1FLAG柱纯化,检测其体外对前列腺癌细胞的细胞毒杀伤活性和在荷瘤裸鼠体内的抑瘤作用。　结果　制备的scFv psm ETA免疫毒素能特异性地与PSM高表达的LNCaP细胞结合,在浓度为100 ng/ml时对80%的LNCaP细胞有体外细胞毒杀伤作用;荷LNCaP前列腺癌裸鼠治疗组及对照组肿瘤大小分别为153mm3 及272mm3 (P<0. 01),显示scFv psm ETA对荷瘤裸鼠有抑制肿瘤生长作用。　结论　重组免疫毒素scFv psm ETA对PSM高表达的前列腺癌细胞LNCaP有体外细胞毒杀伤及体内抑瘤作用。     

抗HER-2加抗CD3双特异抗体抑制胃癌细胞生长的实验研究

目的探讨基因工程抗HER-2 抗CD3双特异抗体(bispecific antibody,BsAb)对表达人表皮生长因子受体2(HER-2/neu)的人胃癌细胞体外及体内生长的影响。方法用MTT方法测定Herceptin、抗CD3和BsAb抗体对胃癌细胞系SGC-7901的抑制率;免疫细胞化学法检测SGC-7901细胞的HER-2表达水平;建立裸鼠模型,将HER-2 CD3 BsAb与效应细胞(正常人外周血淋巴细胞)联合应用,观测各组荷瘤动物的肿瘤生长状况。结果正常对照组、抗CD3单克隆抗体联合效应细胞、Herceptin联合效应细胞及HER2 CD3 BsAb联合效应细胞肿瘤细胞的生长抑制率分别为0、(24.3±1.2)%、(56.2±2.6)%、(91.3±4.1)%各组荷瘤裸鼠与对照组的肿瘤体积为(0.86±0.02) cm~3、(0.52±0.04)cm~3、(0.20±0.06)cm~3、(0.11±0.02)cm~3,与对照组相比差异均有统计学意义(P<0.05),其中HER-2 CD3 BsAb联合效应细胞的抑制作用更为显著,与抗CD3 McAb联合效应细胞、Herceptin联合效应细胞组相比差异也有统计学意义(P<0.05)。结论HER-2/neu是胃癌免疫治疗的有效靶点,基因工程抗HER-2 抗CD3 BsAb在体外及体内均具有有效的抗肿瘤活性。     

抗前列腺特异抗原/抗CD3双特异性单链抗体四聚体的制备

本实验旨在构建人IgG3上游铰链区/p53四价功能域融合基因和抗前列腺特异抗原/抗CD3双特异性单链抗体的基础之上[1],进一步制备该双特异性单链抗体的四聚体.     

抗前列腺特异抗原/抗人CD3双特异性单链抗体基因在HeLa细胞中的表达及亲和活性测定

目的　在HeLa细胞中表达抗前列腺特异抗原 (PSA ) /抗人CD3双特异性单链抗体(scFv)融合基因 ,并进行亲和活性测定。方法　在已经构建抗PSA/CD3双特异性scFv融合基因基础上 ,将融合基因克隆入真核表达载体pSecTag2 B中 ,并转染HeLa细胞进行表达。表达产物纯化后 ,用流式细胞仪进行亲和活性测定。结果　经SDS PAGE和Western印迹实验证实 ,表达产物的Mr约为 65 0 0 0。纯化后经流式细胞仪检测 ,可特异性地结合PC 3细胞和人外周血单个核细胞(PBMC)。结论　获得了可与PC 3细胞和PBMC特异结合的抗PSA/CD3双特异性scFv ,为进一步临床应用奠定了基础。     

抗前列腺特异抗原航CD3双特异性单链抗体四聚体的制备

本实验旨在构建人IgG3上游铰链区／p53四价功能域融合基因和抗前列腺特异抗原／抗CD3双特异性单链抗体的基础之上，进一步制备该双特异性单链抗体的四聚体。     

冷冻消融治疗前列腺癌诱导肿瘤特异性免疫反应

目的:评价经皮冷冻消融治疗局限性前列腺癌前后机体抗肿瘤免疫反应。方法:10例局限性前列腺癌患者行经皮冷冻消融治疗。分别于冷冻治疗前1d、治疗后2周采取外周血,分离外周血单个核细胞(PBMCs)。穿刺活检制备前列腺自身肿瘤和非肿瘤组织溶解物。酶联免疫吸附测定(ELISA)法检测血清TNF-α、IFN-γ、IL-4、IL-10水平,以IFN-γ/IL-4计算Th1/Th2比值。酶联免疫斑点(ELISPOT)试验检测不同组织溶解物刺激下分泌IFN-γ的T细胞数。以人前列腺癌LNCaP细胞和肾癌GRC-1细胞为靶细胞,乳酸脱氢酶(LDH)释放试验检测细胞毒T淋巴细胞(CTL)特异性杀伤活性。结果:与术前比较,冷冻治疗后TNF-α、IFN-γ明显升高,IL-4、IL-10轻度下降,Th1/Th2比值明显升高(P<0.01)。肿瘤组织溶解物刺激后IFN-γ+T细胞数明显增多(P<0.01)。非肿瘤组织溶解物刺激后,IFN-γ+T细胞数无明显变化。冷冻治疗后细胞毒CTL对人前列腺癌细胞株LNCaP特异杀伤活性明显增强,而对人肾癌细胞株GRC-1无明显杀伤活性。随访3～6个月,仅1例患者肿瘤复发。结论:经皮冷冻治疗前列腺癌可诱导机体产生肿瘤特异性免疫反应。     

嵌合T细胞受体的构建及其在T淋巴细胞表面的表达和体外抗肿瘤功能的检测

目的利用基因工程技术构建表达嵌合T细胞受体(ch-TCR)分子的逆转录病毒载体(由抗 erbB2的单链抗体和信号传导链CD3ζ组成),感染预先刺激的小鼠T细胞,使得T细胞能以MHC非限制性的方式在体外识别并杀伤肿瘤细胞,为肿瘤的过继性免疫治疗提供新思路。方法将抗erbB2的单链抗体、CD8分子绞链区、CD3ζ链的跨膜区和胞内段依次克隆入逆转录病毒载体pCMMP中,与另外两个辅助载体pHDM．G和pMD．MLVgag．pol共同转染293T细胞,包装获得病毒颗粒,感染NIH3T3细胞检测病毒滴度。取适量病毒液感染预先刺激的小鼠CD3+T细胞,流式细胞仪检测嵌合受体在细胞表面的表达,非放射性的细胞杀伤试剂盒和ELISA检测试剂盒分别检测T细胞的抗原特异性杀伤和细胞因子分泌的功能。结果成功构建抗erbB2嵌合T细胞受体基因的逆转录病毒载体,检测病毒滴度为(2．1±1．1)×108IP／ml。体外感染T淋巴细胞的效率为(45±5)％。体外能杀伤erbB2+的肿瘤细胞SK-BR-3、D2F2／E2,而对erbB2-的肿瘤细胞 MCF-7、D2F2无杀伤功能,并能分泌Th1型细胞因子GM-CSF和IFN-γ。结论表达抗erbB2嵌合T细胞受体的T淋巴细胞体外具有MHC非限制性的、erbB2抗原特异性的杀伤肿瘤细胞和分泌 Th1型细胞因子的功能,为下一步的体内实验打下基础。     

长期混合淋巴细胞培养-细胞毒实验模型的建立

目的：建立一种能较逼真地模拟移植排斥反应的体外实验模型。方法：利用EB病毒转化的BI林巴母样细胞系作为刺激细胞,诱导同种异体或异种外周血单个核细胞增殖,并分化为效应细胞,然后检测效应细胞对刺激细胞源靶细胞的杀伤活性,建立长期混合淋巴细胞培养,细胞毒实验模型。结果：用不同刺激细胞诱导产生的效应细胞能有效杀伤刺激细胞来源的靶细胞,进一步克隆实验证实这种杀伤效应是由CD8^ 细胞毒性T淋巴细胞（CTL）所致,结论：长期混合淋巴细胞培养－细胞毒实验模型能较逼真地模拟器官移植受者体内发生的由CTL介导的急性排斥反应。     

白细胞介素-7促进CD8+T细胞干扰素-γ的分泌增强小鼠抗乳腺肿瘤的免疫效应

目的 观察白细胞介素(IL)-7是否通过促进CD8+T细胞干扰素-γ(IFN-γ)分泌来增强小鼠抗乳腺肿瘤的免疫效应.方法 荷瘤小鼠瘤体内直接注射IL-7真核表达质粒(pcDNA3-IL-7);免疫磁珠分选CD4+T、CD8+T细胞并体外培养;流式细胞仪检测细胞内干扰素(IFN)-γ的分泌量;酶联免疫吸附试验(ELISA)检测培养上清IFN-γ的量;噻唑蓝(MTT)法检测CD8+T细胞体外杀伤活性;小鼠体内预先注射anti-CD8抗体阻断活化.结果 pcDNA3-IL-7注射组CD8+T细胞内IFN-γ(38.6±4.4)％、CD8+T细胞培养上清IFN-γ( 136.0±11.2) ng/L,与对照组比较,pcDNA3-IL-7明显促进CD8+T细胞IFN-γ表达量(P＜0.05);IL-7处理过的荷瘤小鼠CD8+T细胞杀伤活性显著增强,尤其效靶比为100∶1;小鼠体内预先注射anti-CD8抗体阻断CD8+T细胞活化,显著抑制IL-7抗瘤效应(P＜0.05).结论 IL-7通过促进小鼠体内CD8+T细胞分泌IFN-γ介导抗瘤效应,从而增强小鼠机体抗乳腺肿瘤的免疫反应.     

双特异性单链抗体介导的CIK细胞对结肠癌的体内杀伤作用

目的 观察双特异性单链抗体介导的细胞因子诱导的杀伤细胞(CIK)细胞在体内杀伤结肠癌细胞的作用.方法 将SW1116细胞种植裸鼠后,建立裸鼠结肠癌模型,分为3组分别经尾静脉注入生理盐水、CIK细胞及CIK细胞+双特异性抗体,每周治疗1次,共4周,取出肿瘤组织称重,并计算出各组的抑瘤率.结果 在体内,CIK组和CIK+双抗组均可抑制肿瘤生长,抑瘤率分别为29.70%和65.02%,与对照组比较差异均有统计学意义(P＜0.05).CIK组和CIK+双抗组的瘤体积、瘤重、抑瘤率比较,差异均有统计学意义(P＜0.05).结论 CIK细胞本身可以抑制肿瘤细胞的生长,在加入抗CD3抗癌胚抗原(CEA)双特异性单链抗体后抑瘤作用明显增强.

Abstract：

Objective To investigate the killing effect of cytokine-induced killer cell (CIK) mediated by bispecific single-chain antibody in vivo on colon cancer cells. Methods The colon cancer model in nude mice was established with SW1116 cells. The mice were divided into 3 groups, which were injected with normal saline, CIK cells and CIK cells + bispecific antibody, respectively, once a week for 4 weeks. The tumors were removed and weighed, and the tumore inhibition rate in each group was calculated. Results The CIK cells and CIK cells with bispecific single-chain antibody could both inhibit tumor growth in vivowith the tumor inhibition rate being 29. 70% and 65.02% respectively ( P ＜ 0. 05 ). There was significant difference in tumor inhibition rate between CIK cells and CIK cells with bispecific single-chain antibody ( P ＜ 0. 05 ). Conclusion CIK cells alone can inhibit tumor cell growth, CIK cells in combination with bispecific single-chain antibody can exert more significant antitumor effect.     

Anti-tumor x anti-CD3 heteroconjugates direct human peripheral blood lymphocytes to lyse colon tumor cells

T lymphocytes normally recognize antigens through the antigen receptor complex (TCR/CD3) but can be redirected to bind and lyse unrecognized tumor cells by anti-tumor X anti-CD3 heteroconjugates. Chemical coupling of an antibody directed against the T cell receptor complex and an antibody directed against tumor antigen produces a conjugated antibody that activates the T cell lytic mechanism and bridges the T cell and tumor cell. We tested the lytic activity of heteroconjugate-treated cultured human peripheral blood lymphocytes (PBLs) in 4-h radioactive chromium release assays with human colon tumor cell targets. PBLs were enriched for T cells by the depletion of Leu11a+ and Leu19+ cells, prior to culture in rIL-2 and anti-CD3. Cultured human PBLs depleted of Leu11a+ and Leu19+ cells produced low levels of tumor cell lysis in the absence of antibodies. Anti-tumor X anti-CD3 heteroconjugates significantly enhanced tumor cell lysis by cultured PBLs when tested against four different colon tumor cell lines (P less than 0.005), but, heteroconjugates in the absence of PBLs did not augment tumor cell lysis. Cultured PBLs treated with monoclonal anti-tumor antibody, with monoclonal anti-CD3 antibody, or with irrelevant heteroconjugate did not enhance tumor cell lysis. We conclude that heteroconjugate-directed lysis is mediated by PBLs and that both the anti-tumor antibody and the anti-CD3 antibody are essential for heteroconjugate function. In addition, heteroconjugate-enhanced tumor cell lysis is mediated through a mechanism other than antibody-dependent cellular cytotoxicity or nonspecific T cell receptor crosslinking.(ABSTRACT TRUNCATED AT 250 WORDS)     

Induction of cytotoxicity from human lymphocytes coated with bispecific antibody against human glioma cells

A bifunctional hetero-F (ab') 2 fragment containing the Fab portions from anti-CD3 and anti-glioma monoclonal antibodies was prepared. The antibody simultaneously recognized two different molecules, the CD3 complex on effector T cells and human glioma-associated antigens on target glioma cells. This bispecific F (ab') 2 fragment induced peripheral blood lymphocytes (PBLs) from healthy donors to lyse cells of the human glioma cell line, U251MG, that is resistant to natural killer cell-mediated cytolysis. Compared with lymphokine-activated killer (LAK) activity which is obtained by exposure to interleukin (IL)-2 for more than 3 days, the maximum bispecific antibody-dependent cytotoxicity can be generated only after 24 hour exposure to IL-2. And cytotoxicity of lymphocytes triggered by the bispecific antibody was dependent upon the concentration of IL-2 in the culture medium. The effect of the bispecific antibody on LAK cells was tested in patients suffering from malignant glioma. One patient who received specific targeting therapy (LAK plus bispecific antibody) showed the disappearance of high density tumor mass from CT scan. But the patient who received only LAK therapy showed the recurrence of tumor one year after LAK treatment. These are preliminary data, but may be a promising approach in cancer immunotherapy.     

The mechanism of anti-CD3 monoclonal antibodies. Mediation of cytolysis by inter-T cell bridging

OKT3, an anti-CD3 MAB, depletes T cells in vivo and is among the most potent inhibitors of acute allograft rejection. The mechanism of this inhibition is unknown. The present studies investigate whether anti-CD3 antibodies have the ability to crosslink CD3 on two different cells and induce TCR-dependent antibody-bridged cell-mediated cytolysis (TCR-ABCMC) between T cells. Two different anti-CD3 antibodies (OKT3 and CD3,3) and OKT3 F(ab')2 were all highly effective in inducing cytolysis of CD8+ and CD4+ T cells by CD8+ T cells, and CD8+ T cells by CD4+ T cells. Monovalent OKT3 Fab was 25-125-fold less potent than OKT3 F(ab')2. Monovalent CD3,X was totally ineffective. The necessity for intercellular bridging was evidenced by the observation that an anti-CD3:anti-CD4 (CD3,4) bispecific MAB (BSMAB) was effective in mediating lysis of CD4+ but not CD8+ T cells by CD8+ T cells. These studies indicate that neither FcR-mediated ADCC nor complement fixation is necessary for bivalent anti-CD3 MAB to lyse T cells. Inter-T cell TCR-ABCMC may be particularly effective in inflammatory tissues, such as rejecting allografts and autoimmune diseases, in which numerous cytolytic T lymphocytes are present in close association with other T cells.     

Induction of cytotoxicity in human T cells coated with anti-glioma x anti-CD3 bispecific antibody against human glioma cells

A bifunctional hetero-F(ab')2 antibody fragment was developed that contained the Fab portions from anti-CD3 and anti-glioma monoclonal antibodies. The antibody simultaneously recognized two different molecules, the CD3 complex on effector T cells and a human glioma-associated antigen; thus, it could cross-link effector and target cells. This bispecific F(ab')2 fragment induced peripheral blood mononuclear cells (PBMC's) from healthy donors to lyse cells of the human glioma cell line, U251MG, which are resistant to natural killer cell-mediated cytolysis. The effect of the bispecific antibody on lymphokine-activated killer (LAK) cell activity was tested in patients suffering from malignant glioma. For this study, PBMC's from these patients were preactivated with recombinant interleukin-2 and their killer activity against U251MG cells was investigated in vitro with and without the bispecific antibody. The LAK cell activity of the PBMC's from patients with malignant gliomas was found to be suppressed compared with those of healthy donors. However, after preincubation with bispecific antibody, the patients' LAK cells exhibited marked cytolytic activity against U251MG cells. These findings suggest that this bispecific antibody may be a useful addition to anti-glioma immunotherapy.     

Inhibition of vascular endothelial cell growth factor suppresses the in vivo growth of human prostate tumors

The LNCaP human prostate cancer cell line is androgenand stromal-dependent for in vivo growth. We co-inoculated LNCaP cells with human fetal fibroblasts, isolated from prostate, bone (male), and lung (male and female) derived from 18- to 22-week-old human fetal tissue, into non-castrate male nude mice. Co-inoculation of LNCaP with fetal prostatic fibroblasts resulted in high tumor take rates (27 of 30, or 90%) 6 to 8 weeks after subcutaneous co-inoculation. Serum prostate specific antigen (PSA) values correlated strongly with wet tumor weight (r=0.86). The fetal fibroblast enhancement of tumor take rates in vivo was neither gender- nor organ-specific. Fetal fibroblast-conditioned medium (CM) did not have a significant proliferative effect on LNCaP cell growth in vitro. Areas of angiogenesis were demonstrable in all tumors, with blood vessels arising at the interface between stromal and tumor cells. The fetal fibroblasts, but not the LNCaP cells, expressed significant amounts of the mRNA and protein for vascular endothelial cell growth factor (VEGF). Treatment of tumor-bearing animals with neutralizing antibodies to VEGF resulted in significant tumor growth suppression. These findings indicate that VEGF is an important mediator of stromal-induced enhancement of human prostate cancer cell growth in vivo.     

Inhibition of telomerase is related to the life span and tumorigenicity of human prostate cancer cells.

PURPOSE: Telomerase, the enzyme that catalyzes the elongation of telomeres, is illegitimately activated in the majority of cancers, including that of the prostate, where it may greatly extend the life span of malignant cells. The inhibition of telomerase by molecular intervention has been shown to lead eventually to cell death in several tumor or in vitro immortalized cell lines and in 1 case prevent tumor growth in vivo. Therefore, we tested whether a similar strategy may be used to limit the tumorigenic potential of late stage prostate cancer cells. MATERIALS AND METHODS: PC-3, LNCaP and DU-145 human prostate cancer cells were infected with a retrovirus encoding a dominant-negative version of the catalytic subunit of telomerase (DN-hTERT). Subclones or polyclonal populations were assayed for DN-hTERT expression, telomerase activity, telomere length, cell life span and in most cases tumorigenicity in nude mice. RESULTS: DN-hTERT expression levels directly correlated with cell life span and tumorigenic growth. PC-3 cells expressing high levels of DN-hTERT died rapidly and failed to form tumors in nude mice, whereas cells expressing the lowest levels proliferated the longest and generated tumors that later spontaneously regressed. Similarly the inhibition of telomerase activity in LNCaP cells was greater than in DU-145 cells and correspondingly LNCaP cells had a shorter life span. CONCLUSIONS: DN-hTERT expression limits the life span and tumorigenic potential of human prostate cancer cells, although the onset of these effects appears to be dictated by the expression level of DN-hTERT. Therefore, telomerase represents an attractive target for potentially managing prostate cancer. Nevertheless, effective means of inhibiting the enzyme may be required for a therapeutically useful outcome.     

Inhibition of androgen-sensitive LNCaP prostate cancer growth in vivo by melatonin: association of antiproliferative action of the pineal hormone with mt1 receptor protein expression

BACKGROUND: Potential involvement of the mt1 receptor in the antiproliferative action of melatonin on androgen-sensitive LNCaP cells, and melatonin-induced modulation of androgen-insensitive PC-3 cell growth, have been reported in vitro. The effects of melatonin on prostate cancer cell proliferation and their association with mt1 receptor expression were investigated in athymic nude mice xenograft models of LNCaP and PC-3 cells. METHODS: Daily saline or melatonin (4 microg/g body weight) was given to nude mice before or after tumor cell inoculation. Tumor volume was measured periodically, and expression of PCNA, cyclin A, PSA, and mt1 receptor was assessed by immunohisto(cyto)chemistry and/or Western blotting. RESULTS: Melatonin inhibited the growth of LNCaP tumors, without affecting the growth of PC-3 xenografts, in nude mice. It induced significant decreases in the expression of PCNA, cyclin A, and PSA in LNCaP tumors. Expression of mt1 receptor protein was demonstrated in LNCaP cells, but not in PC-3 cells, both in vivo and in vitro. CONCLUSIONS: The antiproliferative action of melatonin on LNCaP tumor growth was demonstrated in vivo, and its association with mt1 receptor protein expression suggests the potential involvement of the receptor in the antitumor activity of the pineal gland hormone.