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。     

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.     

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。     

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.     

HER2×CD3双抗体治疗过度表达HER2基因裸鼠乳腺癌及其机制

目的　探讨基因工程HER2×CD3双特异性抗体 (BsAb)对过度表达HER2 /neu基因人乳腺癌的治疗效果及其作用机制。方法　建立人乳腺癌异位种植转移模型。 48只裸鼠皮下接种人乳腺癌细胞株BT 474后 ,随机分成 4组 (n =12 ) ,1周后开始 ,分别腹腔内注射磷酸盐缓冲液(PBS ,1ml ,对照组 )、效应细胞 +抗CD3单克隆抗体 (Anti CD3McAb) (0 .85mg/kg ,CD3McAb组 )、效应细胞 +抗HER2单克隆抗体Herceptin(0 .85mg/kg ,Herceptin组 )、效应细胞 +HER2×CD3双特异性抗体 (0 .3 5mg/kg ,BsAb组 ) ,每周 2次 ,共用 3周。第 8周末处死动物 ,测量种植处肿瘤体积、抑瘤率、观察癌细胞转移情况 ,应用Northernblot方法检测HER2 /neumRNA的表达。结果　各组均成瘤 ;BsAb组、Herceptin组、抗CD3组、对照组肿瘤体积和抑瘤率分别为(0 .10± 0 .0 2 )、(0 .2 1± 0 .0 7)、(0 .5 4± 0 .0 5 )、(0 .84± 0 .11)cm3 和 88.1%、75 .0 %、3 7.9%、0 ;腋窝淋巴结转移率分别为 0、16.7%、45 .5 %、10 0 % ;肝转移率分别为 0、16.7%、3 6.4%、75 .0 % ;Northernblot印迹分析示HER2×CD3双特异性抗体明显抑制HER2 /neumRNA表达。Herceptin组和BsAb组乳腺癌生长和转移受到明显抑制 (P <0 .0 5 ) ,尤以BsAb组最明显 (P <0 .0 5 )。结论　基     

抗人γ-精浆蛋白单链抗体四聚体的构建及表达

目的　构建抗γ 精浆蛋白 (γ Sm )单链抗体 (scFv) /p5 3四聚功能域 ( p5 3TD)融合基因 ,并进行真核表达和活性测定。方法　利用递归聚合酶链反应 (PCR)法扩增IgG3上游铰链区与p5 3TD融合基因 ,克隆入 pUC19载体中构建 pUC19/IgG3 /p5 3克隆载体。将抗γ SmscFv克隆入该载体中 ,构建抗γ SmscFv/p5 3TD融合基因并克隆入真核表达载体 pSecTag2 B ,转染HeLa细胞表达纯化后 ,利用流式细胞仪 (FCM )进行活性测定。结果　获得了抗γ SmscFv/p5 3TD融合基因 ,基因全长 891bp ,可编码 2 97个氨基酸。表达产物经十二烷基磺酸钠 聚丙烯酰胺凝胶电泳 (SDS PAGE)和Western印迹实验证实为约 3 5× 10 3 的特异蛋白条带 ,纯化后经流式细胞仪检测可以特异性地结合PC 3细胞 ,亲和力高于scFv。结论　获得了可与PC 3细胞特异结合的四价抗γ SmscFv ,为进一步临床应用奠定基础。     

基因工程HER2/CD3双特异抗体抑制乳腺癌生长的实验研究

近年来人们对难治性乳腺癌发生、发展相关生物学因素的认识不断深入。其中癌基因HER2/neu在乳腺癌诊断和免疫治疗中的研究进展最为显著。我们在成功建立BT-474人乳腺癌模型的基础上,探讨了抗HER2×抗CD3双特异抗体(HER2×CD3BsAb)与正常人外周血淋巴细胞联合应用对过度表达HER2     

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。     

人源性抗前列腺特异性膜抗原单链抗体的基因构建、表达及鉴定

目的:分别构建人源性抗前列腺特异性膜抗原(PSMA)单链抗体(sc Fv)/鱼精蛋白截短体(tp)、sc Fv/弗林蛋白酶识别位点(Fdt)/流感病毒融合肽结构域(HA2)/tp融合蛋白基因。利用原核表达体系表达、纯化并检测sc Fv、sc Fv-tp、sc Fv-Fdt-HA2-tp融合蛋白的活性。方法:采用PCR的方法,扩增融合基因sc Fv、sc Fv-tp、sc Fv-Fdt-HA2-tp,将获得的基因克隆入原核表达载体p ET28,在大肠杆菌BL21中表达,表达产物经SDS-PAGE和Western印迹鉴定,通过Ni2+-NTA螯合层析纯化。ELISA分析融合蛋白抗原亲和活性。结果:成功构建了人源性抗PSMA融合基因,经IPTG诱导后在M15中以包涵体形式表达。表达的目的蛋白均能与PSMA抗原结合。结论:融合蛋白具有结合抗原的活性,为靶向递送siRNA的研究奠定了基础。     

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.     

Induction of Allograft Tolerance by Monoclonal CD3 Antibodies: A Matter of Timing

Despite remarkable progress in organ transplantation through the development of a wealth of immunosuppressive drugs highly effective at controlling acute rejection, two major problems still remain, the loss of transplants due to chronic rejection and the growing number of sensitized recipients due to previous transplants, transfusions or pregnancies. Induction of immune tolerance appears to be the only way to curb this complex situation. Here we describe that a therapy, already successfully used to restore immune tolerance to self‐antigens in overt autoimmunity, is effective at promoting transplant tolerance. We demonstrate that a short low‐dose course with CD3 antibodies started after transplantation, at the time of effector T cell priming to alloantigens, induces permanent acceptance of fully mismatched islet allografts. Mechanistic studies revealed that antigen‐specific regulatory and effector T cells are differentially affected by the treatment. CD3 antibody treatment preferentially induces apoptosis of activated alloreactive T cells which is mandatory for tolerance induction. In contrast, regulatory T cells are relatively spared from CD3 antibody‐induced depletion and can transfer antigen‐specific tolerance thus arguing for their prominent role in sustaining long‐term graft survival.     

Transplantation of Cultured Islets from Two-Layer Preserved Pancreases in Type 1 Diabetes with Anti-CD3 Antibody

We sought to determine whether or not optimizing pancreas preservation, islet processing, and induction immunosuppression would facilitate sustained diabetes reversal after single-donor islet transplants. Islets were isolated from two-layer preserved pancreata, purified, cultured for 2 days; and transplanted into six C-peptide-negative, nonuremic, type 1 diabetic patients with hypoglycemia unawareness. Induction immunosuppression, which began 2 days pretransplant, included the Fc receptor nonbinding humanized anti-CD3 monoclonal antibody hOKT3gamma1 (Ala-Ala) and sirolimus. Immunosuppression was maintained with sirolimus and reduced-dose tacrolimus. Of our six recipients, four achieved and maintained insulin independence with normal HbA1c levels and freedom from hypoglycemia; one had partial islet graft function; and one lost islet graft function 2 weeks post-transplant. The four insulin-independent patients showed prolonged CD4+ T-cell lymphocytopenia; inverted CD4:CD8 ratios; and increases in the percentage of CD4+CD25+ T cells. These cells suppressed the in-vitro proliferative response to donor cells and, to a lesser extent, to third-party cells. Severe adverse events were limited to a transient rash in one recipient and to temporary neutropenia in three. Our preliminary results thus suggest that a combination of maximized viable islet yield, pretransplant islet culture, and preemptive immunosuppression can result in successful single-donor islet transplants.     

A Preliminary Comparison Study of Two Noncrosslinked Biologic Meshes Used in Complex Ventral Hernia Repairs

Background

The biologic materials currently available for hernia repairs are costly and there are limited statistics on recurrences and rates of infection in connection with their use in complex cases.

Methods

We performed a retrospective review and comparison of two types of biologic mesh used at our institution for abdominal hernia repairs spanning a 1-year period. Demographic data and outcomes relating to surgical site infections, hernia recurrences, and mortality were analyzed. Of the 35 patients in the study, 23 patients (Group I) were managed with SurgiMend, a neonatal bovine mesh, and 12 patients (Group II) were managed with Flex HD, a human-derived mesh.

Results

The study cohorts met criteria for high-risk stratification based on body mass index, comorbid conditions, and a high prevalence of contaminated wounds. The overall surgical site infection rate was 17?% for Group I and 50?% for Group II. These differences reached statistical significance when comparing superficial infections but not for deep infections with mesh involvement. Hernia recurrences in Group I were 5?% compared to 33?% in Group II. No deaths were observed.

Conclusions

These preliminary data demonstrate promising short-term outcomes for high-risk complex hernias repaired with biologic mesh, particularly SurgiMend, but the long-term durability of these biological materials is yet to be determined.     

Lack of Role for CsA-Sensitive or Fas Pathways in the Tolerization of CD4 T Cells Via BMT and Anti-CD40L

Anti-CD40L mAb plus bone marrow transplantation (BMT) and recipient CD8 T-cell depletion permits long-term mixed hematopoietic chimerism and systemic donor-specific tolerance to be achieved across full MHC barriers. Initial tolerance is characterized by peripheral deletion of donor-reactive CD4 cells. In regimens using costimulatory blockade without BMT to achieve allograft survival, cyclosporine inhibited graft survival, suggesting that the combination may not be clinically applicable. We assessed the role of cyclosporine-sensitive mechanisms and the mechanisms of T-cell apoptosis involved in the induction of early peripheral CD4+ T-cell tolerance by BMT with anti-CD40L. Neither a short course of cyclosporine (14 days) nor the absence of FAS-mediated activation-induced cell death (AICD) blocked the induction or maintenance of donor-specific tolerance. IL-2 production was not associated with tolerance induction, consistent with the lack of a role for Fas-mediated AICD. Mice in which passive T-cell death was impaired because of constitutive expression of a Bcl-xL transgene did not develop tolerance with this protocol. These data confirm that deletion of donor-reactive T cells is critical for the induction of mixed chimerism and tolerance. However, the mechanisms involved may differ from those involved in costimulatory blockade regimens that do not include BMT.     

Comparison of Combination Plasmapheresis/IVIg/Anti-CD20 Versus High-Dose IVIg in the Treatment of Antibody-Mediated Rejection

Different strategies appear to improve the success in treatment of antibody-mediated rejection (AMR), although no one best method has yet emerged. The objective of this study was to compare the efficacy of the combination of Plasmapheresis/intravenous immunoglobulin (IVIg)/anti-CD20-based regimes versus high-dose IVIg alone in the treatment of AMR. Group A (12 patients) was treated with high-dose IVIg between January 2000 and December 2003; group B (12 patients) was treated by Plasmapheresis/IVIg/anti-CD20 between January 2004 and December 2005. Graft survival at 36 months was 91.7% in group B versus 50% in group A (p = 0.02). Donor-specific human leukocyte antigens (DSA) levels detected by Luminex single antigen (Luminex SA) and ELISA, 3 months postrejection are significantly lower in group B than in group A: DSA ELISA class 2 score 6–8 (p = 0.02), DSA mean intensity of fluorescence (MFI) max (p = 0.009) and DSA mean MFI (p = 0.0004). The persistence of elevated DSA levels posttreatment is more frequent in patients with graft loss as compared to those with preserved renal function: score 6–8 on ELISA (p = 0.04); mean MFI (p = 0.00009) and MFImax (p = 0.018). We conclude that: (1) high dose IVIg alone is inferior to Plasmapheresis/IVIg/anti-CD20 as therapy for AMR and (2)DSA postrejection can be quantified using solid phase assays, showing that 3 months after AMR, DSA levels are higher in patients with graft loss.     

Anti-CD3 immunotoxin prevents low-dose STZ/interferon-induced autoimmune diabetes in mouse.

Autoimmune diabetes was induced with an established model in which 3 daily injections of 95 mg/kg body wt/day streptozocin (STZ) and 2 x 10(4) U interferon-gamma (IFN-gamma) were administered to C57BL/6 mice. Diabetes onset was accompanied by precipitous increases in serum glucose levels and validated by immunoperoxidase studies showing diminished islets in pancreatic tissue sections. Administration of two to three doses of a monoclonal antibody (MoAb) or an immunotoxin (IT) directed against the CD3 epsilon-chain before STZ/IFN-gamma treatment prevented increases in serum glucose and protected islets from damage. IT was made by crosslinking anti-CD3 to a low oligosaccharide-containing fraction of purified ricin toxin A chain (RTA; a catalytic inhibitor of protein synthesis) with a stabilized derivative of 2-iminothiolane. Protection was complete, long-lived, and selective because two different control ITs did not prevent diabetes onset. A second pan T-cell-reactive IT was synthesized by linking the MoAb anti-Ly1 to the same RTA toxin. Anti-Ly1 reacts with the murine homologue of human CD5. Anti-Ly1 RTA also protected against diabetes onset in a dose-dependent manner requiring higher doses and a longer schedule than anti-CD3 or anti-CD3 RTA. These studies demonstrate for the first time the importance of CD3+ and CD5+ cells in diabetes onset in the low-dose STZ/IFN-gamma model and show that anti-CD3, anti-CD3 RTA, or anti-CD5 RTA may be useful in vivo for the treatment of diabetes or perhaps other T-cell-mediated autoimmune diseases. These data may have important therapeutic implications for early autoimmune diabetes in humans.     

Normal Donor Bone Marrow is Superior to Flt3 Ligand-Mobilized Bone Marrow in Prolonging Heart Allograft Survival when Combined with Anti-CD40L (CD154)

Flt3 ligand (FL) administration markedly increases bone marrow (BM) stem cells and immature dendritic cells. We investigated the influence of CD40-CD40Ligand (CD154) pathway blockade on antidonor immunity, cytokine production, microchimerism and heart graft survival in BALB/c (H2d) recipients of fully allogeneic C57BL/10 (H2b) FL-mobilized BM (FL-BM) or normal BM. Anti-CD40L mAb strongly suppressed anti-donor T-cell proliferative responses in recipients of either normal or FL-BM, but was less efficient in inhibiting antidonor cytolytic T-cell (CTL) activity, especially in recipients of FL-BM. Interestingly, CD40L blockade was more effective in recipients of multiple compared with single donor BM infusions. Anti-donor cytokine responses revealed complete impairment of IFN-gamma, IL-4 and IL-10 production in recipients of normal BM and CD40L mAb. By contrast, and in agreement with the CTL data, mice given FL-BM retained ability to produce IFN-gamma CD40-CD40L blockade did not promote microchimerism, as evidenced by immunohistology and real time polymerase chain reaction. Nevertheless, anti-CD40L mAb enhanced heart allograft survival in recipients of FL-BM, but the effect was inferior to that achieved with normal BM. These data provide insight into the influence of growth factor-expanded donor BM and costimulation blockade on antidonor immune reactivity and transplant outcome. The comparatively poor outcome obtained using FL-BM plus anti-CD40L mAb in this model may be ascribed to the failure of effectively interdicting antidonor CTL activity.     

肾移植术后外周血CD3+细胞CD69、CD25及CD71的表达及意义

目的　探讨肾移植患者术后外周血CD3 细胞CD6 9、CD2 5及CD71的表达及其意义。方法　提取患者的外周血淋巴细胞 ,进行CD3·PE和CD6 9/CD2 5 /CD71·FITC的双色免疫荧光标记 ,流式细胞分析仪测定。结果　术后稳定组和环孢素中毒组CD3 细胞CD6 9、CD2 5及CD71的表达均较术前下降 (P <0 .0 5 ) ,而急性排斥反应组和感染组则显著升高 (P <0 .0 1) ,而且其升高的时间比临床确诊要早 1～ 4d。结论　动态监测CD3 细胞CD6 9、CD2 5及CD71的表达将有助于急性排斥的早期诊断和鉴别诊断 ,对及时治疗和抗排斥疗效的评价具有一定意义。     

抗CD3单抗诱导CD4+FoxP3+调节性T细胞分化并缓解小鼠肺移植急性排斥

目的建立小鼠原位左肺移植模型,探究抗CD3单抗缓解肺移植急性排斥损伤的作用机制,为其在临床肺移植的应用提供理论依据。方法选取SPF级野生型BALB/c和C57BL/6小鼠,构建原位左肺移植模型,设置同种同型对照组(C57BL/6→C57BL/6,6只)、同种异型对照组(BALB/c→C57BL/6,6只),同种异型单抗处理组(BALB/c→C57BL/6,4只)。术后第2~6天及第9天每日腹腔注射50g抗CD3单抗。采用苏木精-伊红、马松染色以及CD3/髓过氧化物酶(MPO)免疫组化染色,观察各组移植肺T淋巴细胞和中性粒细胞浸润分布情况,进行急性排斥病理评分;实时荧光定量RT-PCR检测移植肺组织转录因子FoxP3和细胞因子IL-17A、IFN-γ的mRNA表达水平;流式细胞术检测受体小鼠脾脏中FoxP3+调节性T细胞(Treg)占CD4+T细胞的比例。结果移植术后10天,同种同型组移植肺外观呈淡红色,柔软有弹性,病理学检测未见明显的炎症细胞浸润和组织损伤;同种异型对照组移植肺外观呈绛紫色,硬度增加;同种异型单抗处理组外观淡红柔软,与同种异型对照组比较,淋巴细胞、中性粒细胞浸润显著减少,急性排斥损伤病理评分降低。实时荧光定量RT-PCR结果显示,与同种同型组相比,同种异型组移植肺中IL-17A和IFN-γmRNA的表达水平升高;抗CD3单抗可降低移植肺中IL-17A与IFN-γmRNA表达水平,升高FoxP3mRNA表达水平。流式细胞术结果显示,与同种同型、同种异型对照组相比,单抗处理组小鼠脾脏中Treg占CD4+T细胞的比例显著升高。结论抗CD3单抗可诱导CD4+FoxP3+Treg的分化并缓解肺移植急性排斥损伤。