Novel Recombinant Immunoglobulin Forms for Cancer Therap

用于癌症治疗的新型重组免疫球蛋白形式

• 批准号: 7291795
• 负责人: JEFFREY SCHLOM
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7291795
• 关键词: Novel; Recombinant; Immunoglobulin; Forms; Cancer

SDR GRAFTING OF A MURINE ANTIBODY USING MULTIPLE HUMAN GERMLINE TEMPLATES TO MINIMIZE ITS IMMUNOGENICITY. The humanization of mAbs by complementarity-determining region (CDR)-grafting has become a standard procedure to improve the clinical utility of xenogeneic Abs by reducing human anti-murine Ab (HAMA) responses elicited in patients. However, CDR-grafted humanized Abs may still evoke anti-V region responses when administered in patients. To minimize anti-V region responses, the Ab may be humanized by grafting onto the human templates only the specificity-determining residues (SDRs), the residues that are essential for the surface complementarity of the Ab and its ligand. Typically, humanization of an Ab, whether by CDR or SDR grafting, involves the use of a single human template for the entire VL or VH domain of an Ab. We hypothesized, however, that the homology between the human template sequences and mAb to be humanized may be maximized by using templates from multiple human germline sequences corresponding to the different segments of the variable domain. This could be more advantageous in reducing the potential immunogenicity of the humanized Ab. This study describes the SDR grafting of the murine anti-carcinoembryonic antigen (CEA) mAb COL-1 using three different human germline V-kappa sequences as templates for the VL CDRs and another human template for the VL frameworks. In competition RIAs, the SDR-grafted COL-1 (HuCOL-1SDR) completely inhibited the binding of radiolabeled murine COL-1 (mCOL-1) to CEA, and showed that its binding affinity is comparable to that of the CDR-grafted Ab (HuCOL-1). The HuCOL-1SDR showed similar binding reactivity to the CEA expressed on the surface of a tumor cell line as the HuCOL-1. More importantly, compared to HuCOL-1 and the "abbreviated" CDR-grafted Ab, HuCOL-1SDR showed lower reactivity to patients' sera carrying anti-V region Abs to mCOL-1. HuCOL-1SDR, which shows a lower sera reactivity than that of the parental Abs while retaining its Ag-binding property, is a potentially useful clinical reagent. To the best of our knowledge, this is the first time a VL or VH domain of an Ab has been humanized by grafting the SDRs onto a human template comprised of several Ab sequences. We have shown that humanization of an Ab can be optimized using multiple human templates for a single variable domain of an Ab. This approach maximizes the homology between the target Ab and the human templates in both the frameworks and the CDRs by choosing as the template the human sequence that displays the highest local sequence identity to the frameworks and to each of the CDRs of the target Ab.RADIOIMMUNOTHERAPY OF HUMAN COLON CARCINOMA XENOGRAFTS USING A 213BI-LABELED DOMAIN-DELETED HUMANIZED MONOCLONAL ANTIBODY. We have carried out the first study of a humanized domain-deleted monoclonal antibody (HuCC49DeltaCH2) to be utilized in a radioimmunotherapeutic (RIT) application with 213Bi. An initial study indicated that 111In-HuCC49DeltaCH2 targets the subcutaneously implanted human colon carcinoma xenograft, LS-174T, when injected via a peritoneal route. The HuCC49DeltaCH2 was then radiolabeled with 213Bi, an alpha-emitting radionuclide with a half-life of 45.6 minutes, and evaluated for therapeutic efficacy. Dose titration studies indicated that a single dose of 500-1000 microCi, when injected by an intraperitoneal route, resulted in the growth inhibition or regression of the tumor xenograft. The radioimmunotherapeutic effect was found to be dose-dependent. Specificity of the therapeutic efficacy was confirmed in a subsequent experiment with athymic mice bearing TAG-72 negative MIP (human colorectal) xenografts. A preliminary study was also performed to assess a multiple-dose administration of 213Bi-HuCC49DeltaCH2. Doses (500 microCi) were administered at 14-day intervals after tumor implantation.

使用多种人类种系模板对鼠抗体进行SDR嫁接，以最大程度地减少其免疫原性。通过互补性区域（CDR）种植对mAB的人性化已成为改善异构ABS临床实用性的标准程序，通过减少患者引起的人类抗毛碱AB（HAMA）反应。然而，在患者中给药时，CDR枝的人源化ABS仍可能引起抗V区域的反应。为了最大程度地减少抗V区域的反应，仅通过将AB嫁接到人类模板上的特异性确定残基（SDR），这对于AB及其配体的表面互补性至关重要。通常，AB的人性化，无论是通过CDR还是SDR嫁接，都涉及将单个人类模板用于AB的整个VL或VH域。但是，我们假设通过使用来自多个人类种系序列的模板对应于变量域的不同段的模板，可以最大化人类模板序列和MAB之间的同源性。这对于降低人源化AB的潜在免疫原性可能更有优势。这项研究描述了使用三种不同的人类生殖线V-kappa序列作为VL CDR的模板和VL框架的另一种人类模板，介绍了鼠抗抗癌抗原（CEA）MAB COL-1的SDR嫁接。在竞争性RIA中，SDR-GRAFT的COL-1（HUCOL-1SDR）完全抑制了放射标记的鼠Col-1（MCOL-1）与CEA的结合，并表明其结合亲和力与CDR-GRAFT的AB（Hucol-1）相当。 HUCOL-1SDR显示出与在肿瘤细胞系表面与Hucol-1表达的CEA相似的结合反应性。更重要的是，与Hucol-1和“缩写”的CDR-GRAFT AB相比，Hucol-1SDR对携带抗V区域ABS的患者血清的反应性较低。 HUCOL-1SDR是一种潜在有用的临床试剂，其血清反应性比亲本ABS的AG abs较低。据我们所知，这是AB的VL或VH域首次通过将SDR嫁接到由几个AB序列组成的人类模板上来人性化的。我们已经表明，可以使用多个人体模板对AB的单个变量域进行优化AB的人性化。这种方法通过选择模板作为模板，使用213bi人类的人类XAn tormit domains domains tomabib notains tormabibs，这种方法通过选择对框架的最高局部序列身份，并向目标AB.Radiomunmunotheration的每个CDR显示人类结肠癌癌的人类Xenogrized Monorate Monoratib domains domains domains domains domains domains domains domains promains sob and框架和CDR中的目标AB与人类模板之间的同源性。我们已经对人性化结构域缺失的单克隆抗体（HUCC49DELTACH2）进行了首次研究，该抗体可用于213BI的放射免疫疗法（RIT）。一项最初的研究表明，当通过腹膜途径注射时，111in-Hucc49deltach2靶向皮下植入的人类结肠癌异种移植物LS-174T。然后将HUCC49DELTACH2用213Bi放射性标记，这是一种α发射放射性核素，半衰期为45.6分钟，并评估了治疗功效。剂量滴定研究表明，当通过腹膜内途径注射时，单剂量为500-1000微米，导致肿瘤异种移植物的生长抑制或退化。发现放射免疫疗法效应是剂量依赖性的。随后对带有TAG-72阴性MIP（人结直肠）异种移植的无胸腺小鼠的实验证实了治疗功效的特异性。还进行了一项初步研究，以评估213BI-HUCC49DELTACH2的多剂量给药。肿瘤植入后以14天的间隔给予剂量（500毫米）。