嵌合型单克隆抗体CD20诱导难治性套细胞淋巴瘤完全缓解一例

患者 ,男 ,5 3岁 ,马来西亚华侨。于 1997年 2月无明显诱因出现左上腹疼痛、不适 ,就诊新加坡国立医院 ,经检查发现颈部淋巴结、脾肿大 ,2月 2 7日在新加坡国立医院行颈部淋巴结活检 ,同时行免疫组化染色检查 :Ｌ2 6 (+) ,ＣＤ2 0 (+) ,ＣＤ45(+) ,ＣＤ3 (- ) ,诊断为套细胞淋巴瘤 ⅣＡ ,行ＣＨＯＰ(环磷酰胺、阿霉素、长春新碱、泼尼松 )方案化疗 6个疗程于 6月 19日结束 ,病情稳定。 1997年 12月体重明显下降 ,ＣＴ检查示脾大 ,骨髓穿刺发现淋巴瘤细胞浸润 ,给予ＢＣＨＯＰ方案+ＭＴＸ 1个疗程后复查骨髓未见异常 ,1998年 8月 17日行自体…     

抗人CD20单克隆抗体治疗B细胞淋巴瘤研究进展

近年来,对B细胞淋巴瘤的抗原靶向性治疗已取得了巨大进展。出现了一种新的非常有发展前景的治疗方法。即以B细胞分化抗原CD20为靶抗原的单克隆抗体（McAb)疗法。CD20是非糖基化的跨膜磷酸蛋白,分子质量为35kD。表达在大多数成熟B细胞表达,分化为浆细胞后,CD20表达消失。CD20可能参与B细胞成熟与分化的调节,作为钙离子通道发挥某些生物学作用。更为重要的是,95%以上的B细胞淋巴瘤表达CD20,且无显内化及脱落,这些特点使其成为单克隆抗体疗法的理想靶抗原,临床试验结果表明,抗CD20单克隆抗体既可单独应用,亦可作为放射性同位素或细胞毒制剂的载体,其疗效显,且使用安全,副反应小,许多研究报道已阐明了抗CD20单克隆抗体治疗B细胞淋巴瘤的几种可能的效应机制。目前,人们正致力于探索一些新的治疗策略以期提高这种疗法的特异性,减少其非特异性的毒副作用。     

抗CD20单克隆抗体美罗华治疗B细胞淋巴瘤的研究进展

美罗华（Rituximab）是一种抗CD20嵌合型单克隆抗体。它可特异性地与B淋巴细胞表面CD20抗原结合，通过多种机制清除体内的B淋巴细胞。临床资料显示，美罗华治疗B细胞非霍奇金淋巴瘤有效率高，毒副反应小，病人耐受良好，是一种有前途的抗肿瘤新药。     

抗CD20单克隆抗体诱导B淋巴瘤细胞株凋亡的实验研究

本研究探讨抗CD20单克隆抗体体外诱导B淋巴细胞株凋亡情况及其可能的作用机制。体外培养Daudi、Ramos、Namalwa和Raji细胞,采用XTT法测定细胞增殖抑制率;用流式细胞术测定细胞凋亡;Western blot测定Daudi、Ramos、Raji和Namalwa细胞经Rituximab 20μg／ml作用24小时后Bcl-2的表达情况。结果表明：抗cD20单克隆抗体对Daudi、Raft和Namalwa淋巴瘤细胞有轻度的抗增殖作用,对Ramos细胞无抗增殖作用,抗增殖作用与单克隆抗体作用浓度无关。抗CD20单克隆抗体对4株细胞无明显诱导凋亡作用,抑制率在3％-10％之间波动。Na—malwa和Raji细胞株经抗CD20单克隆抗体作用24小时后,Bcl-2蛋白表达下调。结论：单药抗CD20单克隆抗体对Daudi、Namalwa和Raji细胞株有轻度抗细胞增殖作用,但与作用浓度和作用时间无明显相关。单药抗CD20单克隆抗体对Daudi、Namalwa、Raji和Ramos细胞株有微弱的诱导凋亡作用。Namalwa和Raji细胞株经抗CD20单克隆抗体作用24小时后Bcl-2表达下调,这可能是抗CD20单克隆抗体增敏细胞毒药物作用的机制之一。     

抗CD20单克隆抗体提高淋巴瘤细胞对X射线的敏感性

本研究观察抗CD20单克隆抗体制剂利妥昔（RTX）对X射线所致的人淋巴瘤细胞损伤的影响。用SRB法检测细胞存活,FITC-Annexin—V／PI试剂盒测定细胞凋亡,透射电子显微镜观察细胞形态,激光共聚焦显微镜检测胞质内钙离子浓度。结果显示,RTX可明显增强X射线时的肿瘤细胞生长抑制作用（P〈0．05）;与单照射组比较,RTX可增加辐射诱导的细胞凋亡;透射电子显微镜下可见多种凋亡表现;细胞内[Ca^2＋]离子明显升高。结论：RTX可提高淋巴瘤细胞对X射线的辐射敏感性,诱导较多细胞的凋亡,并且与细胞内钙离子的变化有关。     

CD20单克隆抗体治疗中枢神经系统淋巴瘤一例

患者 ,男 ,71岁。因耳鸣、右侧肢体麻木 1个月 ,于 2 0 0 1年 3月 30日入院。查体 :睑结膜苍白 ,右侧鼻唇沟变浅 ,伸舌居中 ,颈部可闻及血管杂音。四肢肌力 5级 ,右侧腱反射略亢进 ,右下肢病理征 (+) ,右半身感觉减退。患者于 1997年颈椎核磁共振 (ＭＲＩ)示Ｃ2～ 7椎体后缘纵韧带肥厚伴钙化 ,Ｃ4～ 7椎间盘脱出。 2 0 0 0年头颅ＭＲＩ示双侧脑室前角多发性腔基梗塞 ;血管显示多处狭窄包括双侧大脑中动脉、双颈内虹吸部、右大脑前近段。入院后复查颈椎及头颅ＭＲＩ与既往相比无变化。患者右侧肢体麻木加重 ,出现左上肢及右嘴角麻木 ,双上肢…     

抗CD20单克隆抗体美罗华治疗B细胞淋巴瘤的研究进展

美罗华(Rituximab)是一种抗CD20嵌合型单克隆抗体。它可特异性地与B淋巴细胞表面CD20抗原结合,通过多种机制清除体内的B淋巴细胞。临床资料显示,美罗华治疗B细胞非霍奇金淋巴瘤有效率高,毒副反应小,病人耐受良好,是一种有前途的抗肿瘤新药。     

CD20单克隆抗体联合自体干细胞移植治疗非霍奇金淋巴瘤

大剂量放、化疗结合自体干细胞移植(ASCT)虽然可明显提高非霍奇金淋巴瘤(NHL)患者的缓解率,延长其缓解期,但最终仍有40%～70%的患者复发.CD20单克隆抗体(CD20mAb)通过独特的机理可以有效地清除移植物中污染的肿瘤细胞以及移植后残存的少量肿瘤细胞而明显提高了ASCT的疗效.本文就CD20mAb在ASCT治疗NHL中的移植前化疗、体内外净化、预处理及移植后巩固治疗等方面的应用进行综述.     

CD20单克隆抗体联合自体干细胞移植治疗非霍奇金淋巴瘤

大剂量放、化疗结合自体干细胞移植(ASCT)虽然可明显提高非霍奇金淋巴瘤(NHL)患者的缓解率，延长其缓解期，但最终仍有40％～70％的患者复发。CD20单克隆抗体(CD20mAb)通过独特的机理可以有效地清除移植物中污染的肿瘤细胞以及移植后残存的少量肿瘤细胞而明显提高了ASCT的疗效。本文就CD20mAb在ASCT治疗NHL中的移植前化疗、体内外净化、预处理及移植后巩固治疗等方面的应用进行综述。     

非霍奇金淋巴瘤单克隆抗体治疗的研究进展

单克隆抗体应用于临床治疗恶性淋巴瘤目前已经取得了明显成效,与传统治疗相比,具有靶向性、不良反应小、能达到体内肿瘤细胞的微量残留等特点。新的抗CD20单克隆抗体为非霍奇金淋巴瘤治疗带来了新的发展,对以美罗华为代表单克隆抗体治疗恶性淋巴瘤的耐药问题带来了新的突破,提出了新策略。     

抗CD47单克隆抗体(B6H12)对人树突状细胞成熟及其功能的影响

为阐明可溶性的抗CD47单克隆抗体(B6H12)对树突状细胞(DC)的免疫调控作用及分子机理.联合应用 rhGM-CSF、IL-4、细菌脂多糖(LPS)在体外诱导扩增人外周血单核细胞来源的DC,并在培养体系中添加抗CD47单 克隆抗体(B6H12);采用透射电镜观察DC形态,流式细胞术检测DC膜表面分子的表达;ELISA法检测DC释放的 IL-12 P70水平;BrdU-ELISA法检测DC刺激同种异型淋巴细胞增殖,凝胶电泳迁移率改变实验(EMSA)检测NF-κB 结合活性变化。结果发现:①经抗CD47单克隆抗体(B6H12)处理的DC,膜表面标记(CD80、CD86、CD1a、CD83、 DR)的表达显著地低于未加B6H12单克隆抗体DC组(P<0.05);其释放IL-12 P70蛋白质的能力及刺激同种异 型淋巴细胞增殖的能力也显著低于对照组(P<0.01)。②与未加B6H12单克隆抗体DC组相比,B6 H12单克隆抗 体处理DC组的NF-κB活性显著降低(P<0.05),并且这种抑制作用随单克隆抗体浓度增大而增强。结论:可溶 性的抗CD47单克隆抗体通过抑制NF-κB的结合活性,影响着DC向成熟发育及功能。     

Notch配体Delta-1ike1对小鼠骨髓细胞来源的树突状细胞分化和抗原呈递功能的影响

本研究探讨Notch配体Delta—likel（Dil1）对小鼠骨髓细胞来源的树突状细胞（dendriticcell,DC）分化及其抗原呈递功能的影响。在GM—CSF和IL4存在条件下,用OP9-Dil1和OPt）．GFP细胞分别与小鼠骨髓细胞共培养8天,经肿瘤抗原刺激成熟。用流式细胞仪检测DC表面MHCII、CD80和CD86的表达情况,ELISA法检测肿瘤抗原刺激后DC培养上清细胞因子IL-12和IL110的水平,通过混合T淋巴细胞反应观察DC对T细胞的促增殖能力。结果表明：与GFP组相比,Dll1组的小鼠骨髓来源的树突状细胞明显增多（P〈0．05）。肿瘤抗原刺激后,Dll1组DC表面MHCII、CD80和CD86表达量更高。DC分泌的IL-12水平显著高于对照组（P〈0．05）,而IL-10的水平显著低于对照组（P〈0．01）。Dll1组DC具有更强的促T细胞增殖活性。结论：OP9-Dll1促进小鼠骨髓细胞向DC分化并增强其抗原呈递功能。     

抗CD28抗体协同刺激增强抗CD3抗体体外激活T淋巴细胞并降低TGF-β的表达

为了探讨体外激活T淋巴细胞的方法及活化后T淋巴细胞的免疫学特征,利用抗CD3、抗CD28抗体在体外刺激健康人外周血单个核细胞PBMNC,检测淋巴细胞转化,CD8^＋CD25^＋细胞比例和肿瘤生长因子β（TGF-β）表达等相关免疫学指标.结果表明,在抗CD28抗体的协同作用下,抗CD3抗体的刺激活性明显提高,CD8^＋CD25^＋细胞比例明显增加,TGF-β的表达下调.结论：抗CD28抗体协同刺激可以提供第二信号,使T淋巴细胞充分活化,TGF-β表达水平明显下降.     

Anti-CD22 Antibody Targeting of pH-responsive Micelles Enhances Small Interfering RNA Delivery and Gene Silencing in Lymphoma Cells

The application of small interfering RNA (siRNA) for cancer treatment is a promising strategy currently being explored in early phase clinical trials. However, efficient systemic delivery limits clinical implementation. We developed and tested a novel delivery system comprised of (i) an internalizing streptavidin-conjugated monoclonal antibody (mAb-SA) directed against CD22 and (ii) a biotinylated diblock copolymer containing both a positively charged siRNA condensing block and a pH-responsive block to facilitate endosome release. The modular design of the carrier facilitates the exchange of different targeting moieties and siRNAs to permit its usage in a variety of tumor types. The polymer was synthesized using the reversible addition fragmentation chain transfer (RAFT) technique and formed micelles capable of binding siRNA and mAb-SA. A hemolysis assay confirmed the predicted membrane destabilizing activity of the polymer under acidic conditions typical of the endosomal compartment. Enhanced siRNA uptake was demonstrated in DoHH2 lymphoma and transduced HeLa-R cells expressing CD22 but not in CD22 negative HeLa-R cells. Gene knockdown was significantly improved with CD22-targeted vs. nontargeted polymeric micelles. Treatment of DoHH2 cells with CD22-targeted polymeric micelles containing 15 nmol/l siRNA produced 70% reduction of gene expression. This CD22-targeted polymer carrier may be useful for siRNA delivery to lymphoma cells.     

Inactivation of a Defined Active Site in the Mouse 20S Proteasome Complex Enhances Major Histocompatibility Complex Class I Antigen Presentation of a Murine Cytomegalovirus Protein

Proteasomes generate peptides bound by major histocompatibility complex (MHC) class I molecules. Avoiding proteasome inhibitors, which in most cases do not distinguish between individual active sites within the cell, we used a molecular genetic approach that allowed for the first time the in vivo analysis of defined proteasomal active sites with regard to their significance for antigen processing. Functional elimination of the δ/low molecular weight protein (LMP) 2 sites by substitution with a mutated inactive LMP2 T1A subunit results in reduced cell surface expression of the MHC class I H-2L^d and H-2D^d molecules. Surface levels of H-2L^d and H-2D^d molecules were restored by external loading with peptides. However, as a result of the active site mutation, MHC class I presentation of a 9-mer peptide derived from a protein of murine cytomegalovirus was enhanced about three- to fivefold. Our experiments provide evidence that the δ/LMP2 active site elimination limits the processing and presentation of several peptides, but may be, nonetheless, beneficial for the generation and presentation of others.     

Safety, Pharmacokinetics, and Antiretroviral Activity of Multiple Doses of Ibalizumab (formerly TNX-355), an Anti-CD4 Monoclonal Antibody, in Human Immunodeficiency Virus Type 1-Infected Adults

Ibalizumab (formerly TNX-355) is a humanized monoclonal antibody that binds CD4, the primary receptor for human immunodeficiency virus type 1 (HIV-1), and inhibits the viral entry process. A phase lb multidose study of the safety, pharmacokinetics, and antiviral activity of ibalizumab was conducted with 22 HIV-1-infected patients. Nineteen patients were randomized to receive either 10 mg/kg of body weight weekly (arm A) or a 10-mg/kg loading dose followed by 6 mg/kg every 2 weeks (arm B) intravenously for 9 weeks. Three patients were assigned to receive 25 mg/kg every 2 weeks for five doses (arm C). During the study, the patients remained off other antiretrovirals or continued a stable failing regimen. Treatment with ibalizumab resulted in substantial reductions in HIV-1 RNA levels (0.5 to 1.7 log₁₀) in 20 of 22 subjects. In most patients, HIV-1 RNA fell to nadir levels after 1 to 2 weeks of treatment and then returned to baseline despite continued treatment. Baseline viral isolates were susceptible to ibalizumab in vitro, regardless of coreceptor tropism. Emerging resistance to ibalizumab was manifested by reduced maximal percent inhibition in a single-cycle HIV infectivity assay. Resistant isolates remained CD4 dependent and were susceptible to enfuvirtide in vitro. Complete coating of CD4⁺ T-cell receptors was correlated with serum ibalizumab concentrations. There was no evidence of CD4⁺ T-cell depletion in ibalizumab-treated patients. Ibalizumab was not immunogenic, and no serious drug-related adverse effects occurred. In conclusion, ibalizumab administered either weekly or biweekly was safe and well tolerated and demonstrated antiviral activity. Further studies with ibalizumab in combination with standard antiretroviral treatments are warranted.     

Transforming Growth Factor β1, in the Presence of Granulocyte/Macrophage Colony-stimulating Factor and Interleukin 4, Induces Differentiation of Human Peripheral Blood Monocytes into Dendritic Langerhans Cells

Langerhans cells (LCs) are dendritic cells (DCs) that are present in the epidermis, bronchi, and mucosae. Although LCs originate in bone marrow, little is known about their lineage of origin. In this study, we demonstrate that in vitro LCs may originate from monocytes. Adult peripheral blood CD14⁺ monocytes differentiate into LCs (CD1a⁺, E-cadherin⁺, cutaneous lymphocyte-associated antigen⁺, Birbeck granules⁺, Lag⁺) in the presence of granulocyte/macrophage colony-stimulating factor, interleukin 4, and transforming growth factor β1 (TGF-β1). This process occurs with virtually no cell proliferation and is not impaired by 30 Gy irradiation. Selection of monocyte subpopulations is ruled out since monocyte-derived DCs can further differentiate into LCs. Our data suggest that in vivo LC differentiation may be induced peripherally, from a nonproliferating myeloid precursor, i.e., the monocyte, in response to a TGF-β1–rich microenvironment, as found in the skin and epithelia. Therefore, the monocyte may represent a circulating precursor critical to the immune response in vivo.