治疗性单克隆抗体研究进展

杂交瘤技术使鼠源单克隆抗体（鼠单抗）被广泛用于人类疾病的诊断和研究,建立了治疗性抗体的第一个里程碑。但随后出现的人抗鼠抗体等副作用极大地限制了鼠单抗的临床应用。随着生物学技术的发展和抗体基因结构的阐明,应用DNA重组技术和抗体库技术对鼠单抗进行人源化改造,先后出现了嵌合抗体、改型抗体和全人抗体,同时也涌现了各种单抗衍生物,它们从不同角度克服了鼠单抗临床应用的不足,未人类疾病治疗带来新的曙光。我们就上述治疗性抗体人源化的研究进展做简要综述。     

治疗性抗体的研究进展

作为一种具有靶向性的生物大分子,单克隆抗体始终是人们关注的热点之一,被广泛用于治疗肿瘤、病毒感染和抗移植排斥等。但鼠源单克隆抗体的临床应用受限于诱导产生人抗鼠抗体、肿瘤渗入量低、亲和力低和半衰期短等。随着分子生物学技术的发展及其向各学科的渗透,通过基因操作技术对抗体进行改造,可使其适用于多种疾病的治疗。抗体人源化已经成为治疗性抗体的发展趋势,同时各种抗体衍生物也不断涌现,它们从不同角度克服了抗体本身的应用局限,也为治疗人类疾病提供了利器。本文简要介绍上述技术的基本原理、特点和治疗性抗体的研究进展。     

人源化抗体制备及其应用研究进展

伴随着一系列重大生物技术(如PCR技术、抗体库技术、转基因动物技术等)的发展,抗体技术从最初的嵌合抗体、改型抗体逐渐发展为今天的人源化抗体。人源化抗体在治疗肿瘤、自身免疫性疾病和器官移植等方面已经显示出独特的优势和良好的应用前景。介绍了人源化抗体的构建及其表达系统,并对其临床应用进行了展望。     

重组抗体药物研究进展及应用

重组抗体药物的发展经历了鼠源单克隆抗体（McAb）、人 鼠嵌合抗体、人源化抗体和全人抗体等阶段,目前初步应用于抗肿瘤、抗自身免疫病、抗感染等领域。保持和提高抗体的亲和力、降低抗体的免疫原性是抗体药物基因工程改造的两大原则。在嵌合抗体成功的基础上,通过CDR移植、表面修饰、抗体库以及转基因鼠技术,逐步提高人源化程度至100%。然而,实验室水平的研究结果与实际应用仍然存在一定差距。就重组抗体药物的基本概况、现存的问题与可能的解决办法以及在肿瘤、病毒性疾病和阿尔茨海默病治疗上的应用情况等进行了综述。     

抗体技术的发展现状及其在肿瘤治疗中的应用

抗体技术有一百多年的历史,单克隆抗体有近30年的历史,但由于抗鼠抗体（HAMA）的形成,使抗体在人体中的应用受到局限,近年来由于DNA重组技术的发展,利用基因工程技术可以实现将鼠抗体人源化或生产人源抗体,克服HAMA,为抗体的临床应用提供了新的研究方法和思路,本分别介绍抗体技术的发展状况及其在治疗肿瘤方面的应用。     

抗体药物的发展与应用

早期抗体药物是鼠源单克隆抗体,存在免疫原性强、半衰期短等问题。历经数十年的发展,抗体药物从最初的鼠源单抗,逐步发展为人鼠嵌合抗体、人源化抗体及全人源化抗体。通过片段重组、位点修饰、药物偶联等方法,科研人员研发了包括抗体融合蛋白、抗体偶联药物、双特异性抗体、小分子抗体片段等形式多样的抗体药物。抗体药物在恶性肿瘤、自身免疫病、感染性疾病的治疗上发挥重要作用。通过对抗体药物人源化历程,不同类型的抗体结构和特点,以及抗体药物在新型冠状病毒肺炎治疗中的应用进行综述,并对抗体药物的发展前景进行展望,以期为我国抗体药物的研发提供参考。     

单克隆抗体的研究进展

单克隆抗体是一种由骨髓瘤细胞和带有抗体的B淋巴细胞结合形成的杂交瘤细胞,简称单抗。首先,本文对单克隆抗体的研究发展历程进行了分析和探讨,指出单克隆抗体的发展历程包括鼠源性单抗、嵌合抗体、人源化抗体以及人源性抗体这四大阶段,分别对其优缺点进行了说明;接下来,又对单克隆抗体在临床上的应用进行了说明,从疾病诊断方面及疾病的治疗两方面进行探讨。     

人源抗体制备及临床应用研究进展

与常规治疗药物相比,抗体药物具有靶向性强、特异性好等优点,其作为一类重要的治疗性药物,近年来在临床中的应用逐渐增多,为疾病的治疗提供了新的选择,应用范围逐渐从肿瘤、自身免疫性疾病及慢性炎症扩展到心血管和感染性等疾病中。人源抗体的全部结构是由人类抗体基因所编码的,因此避免了异种蛋白长期应用引起的不良反应,加之人源抗体制备技术的不断发展完善,使其逐渐成为治疗性抗体研发的首要选择。综述了近年来治疗性人源抗体的主要制备技术及其在临床中应用的最新进展,同时探讨了人源抗体制备技术的不足之处,以期为人源抗体的发展提供借鉴和思路。     

人B细胞永生化研究进展

人源单克隆抗体具有免疫原性低、半衰期长等优势,成为了体内应用中不可或缺的生物制剂.人类抗体库为人源单克隆抗体的制备提供了丰富的来源,人B细胞永生化是获得人类抗体库的潜在有效方法,可应用于人源单克隆抗体的制备.由于各平台均有亟待解决的问题,基于人B细胞永生化的抗体制备尚局限在实验室研究阶段,且目前尚缺乏一篇系统综述以明确...     

抗乙型脑炎病毒人源化单链抗体的构建及其表达

单克隆抗体以其特异性强、均～性好的特点在疾病治疗中已显示了良好的应用前景,但由f目前所用单抗多为鼠源性抗体,进行治疗时,由f多次使用或多剂量使用,会刺激人体产生抗鼠抗体（HAMA）的排斥反应,这不仅减弱了单抗的治疗效果,而且还会使人体产生其它副反应,从而阻碍了单抗治疗的进程。抗体工程技术的发展,使人们可以利用分子生物学手段对抗体进行人源化改造,这不仅降低了抗体中的鼠源成份,可以使鼠源抗体的免疫原性减弱,有利于抗体的临床应用。本文利用表面重塑法对抗乙脑抗体可变区基因进行了人源化改造。1材料与方法工．三…     

Stability of murine, chimeric and humanized antibodies against pre-S2 surface antigen of hepatitis B virus

We have constructed a humanized antibody with specificity for the pre-S2 surface antigen of hepatitis B virus (HBV) by grafting the complementarity determining regions (CDRs) of parental murine monoclonal antibody (mAb) into human anti-Sm antibody framework regions. The humanized antibody has a substitution at position 94 in a framework region of the heavy chain variable region, and exhibits the same antigen binding affinity as the parental murine monoclonal and chimeric antibodies. In order to assess the stability of these antibodies, thermal inactivation of the parental, chimeric and humanized antibodies was analyzed. Fifty percent inactivation of the chimeric and humanized antibodies was observed at 63.7 degrees C and 68.7 degrees C, respectively, compared to 55.0 degrees C for murine antibody. The humanized antibody also exhibited increased stability against denaturant. Guanidine-induced unfolding monitored by the changes in fluorescence intensity at 360 nm showed that midpoints of the transition of the chimeric and humanized antibodies were 2.47 M and 2.56 M, respectively, whereas that of the murine antibody was 1.36 M.     

Have we overestimated the benefit of human(ized) antibodies?

The infusion of animal-derived antibodies has been known for some time to trigger the generation of antibodies directed at the foreign protein as well as adverse events including cytokine release syndrome. These immunological phenomena drove the development of humanized and fully human monoclonal antibodies. The ability to generate human(ized) antibodies has been both a blessing and a curse. While incremental gains in the clinical efficacy and safety for some agents have been realized, a positive effect has not been observed for all human(ized) antibodies. Many human(ized) antibodies trigger the development of anti-drug antibody responses and infusion reactions. The current belief that antibodies need to be human(ized) to have enhanced therapeutic utility may slow the development of novel animal-derived monoclonal antibody therapeutics for use in clinical indications. In the case of murine antibodies, greater than 20% induce tolerable/negligible immunogenicity, suggesting that in these cases humanization may not offer significant gains in therapeutic utility. Furthermore, humanization of some murine antibodies may reduce their clinical effectiveness. The available data suggest that the utility of human(ized) antibodies needs to be evaluated on a case-by-case basis, taking a cost-benefit approach, taking both biochemical characteristics and the targeted therapeutic indication into account.     

基因工程抗体研究进展

临床治疗中人抗鼠抗体反应的出现使鼠源性单克隆抗体的应用受到了极大的限制。为降低其免疫原性,人们利用基因工程技术对鼠源抗体进行改造,以减少其鼠源成分。简要概述了目前研究比较多的几种基因工程抗体及其临床应用。     

Have we overestimated the benefit of human(ized) antibodies?

The infusion of animal-derived antibodies has been known for some time to trigger the generation of antibodies directed at the foreign protein as well as adverse events including cytokine release syndrome. These immunological phenomena drove the development of humanized and fully human monoclonal antibodies. The ability to generate human(ized) antibodies has been both a blessing and a curse. While incremental gains in the clinical efficacy and safety for some agents have been realized, a positive effect has not been observed for all human(ized) antibodies. Many human(ized) antibodies trigger the development of anti-drug antibody responses and infusion reactions. The current belief that antibodies need to be human(ized) to have enhanced therapeutic utility may slow the development of novel animal-derived monoclonal antibody therapeutics for use in clinical indications. In the case of murine antibodies, greater than 20% induce tolerable/negligible immunogenicity, suggesting that in these cases humanization may not offer significant gains in therapeutic utility. Furthermore, humanization of some murine antibodies may reduce their clinical effectiveness. The available data suggest that the utility of human(ized) antibodies needs to be evaluated on a case-by-case basis, taking a cost-benefit approach, taking both biochemical characteristics and the targeted therapeutic indication into account.Key words: immunogenicity, human anti-mouse antibody, cytokine release syndrome     

Current perspectives on therapeutic antibodies

Since the first monoclonal antibody, muromonab-CD3, was approved for therapeutic use in 1986, numerous molecules have been targeted using therapeutic antibody technology, resulting in 26 therapeutic antibodies being approved by the US FDA as of November, 2009. Initial concerns regarding antibody drugs focused on immunogenicity, short serum half-life, and weak efficacy. As the types of antibodies progressed from murine to chimeric, humanized, and fully human antibodies, great progress has been made in immunogenicity and in vivo instability issues. For example, humanized antibodies, such as bevacizumab, exhibit less than 0.2% immunogenicity and a 20 day serum half-life, which is comparable to native immunoglobulin. Some recently developed antibodies are exceedingly efficacious and have become first-line therapy for their target diseases. Here, we address and analyze all clinically approved therapeutic antibodies to date by discussing immunogenicity, half-life, and efficacy.     

Specific binding of the pathogenic prion isoform: development and characterization of a humanized single-chain variable antibody fragment

Murine monoclonal antibody V5B2 which specifically recognizes the pathogenic form of the prion protein represents a potentially valuable tool in diagnostics or therapy of prion diseases. As murine antibodies elicit immune response in human, only modified forms can be used for therapeutic applications. We humanized a single-chain V5B2 antibody using variable domain resurfacing approach guided by computer modelling. Design based on sequence alignments and computer modelling resulted in a humanized version bearing 13 mutations compared to initial murine scFv. The humanized scFv was expressed in a dedicated bacterial system and purified by metal-affinity chromatography. Unaltered binding affinity to the original antigen was demonstrated by ELISA and maintained binding specificity was proved by Western blotting and immunohistochemistry. Since monoclonal antibodies against prion protein can antagonize prion propagation, humanized scFv specific for the pathogenic form of the prion protein might become a potential therapeutic reagent.     

The immunogenicity of humanized and fully human antibodies

Monoclonal antibodies represent an attractive therapeutic tool as they are highly specific for their targets, convey effector functions and enjoy robust manufacturing procedures. Humanization of murine monoclonal antibodies has vastly improved their in vivo tolerability. Humanization, the replacement of mouse constant regions and V framework regions for human sequences, results in a significantly less immunogenic product. However, some humanized and even fully human sequence-derived antibody molecules still carry immunological risk. To more fully understand the immunologic potential of humanized and human antibodies, we analyzed CD4+ helper T cell epitopes in a set of eight humanized antibodies. The antibodies studied represented a number of different VH and VL family members carrying unique CDR regions. In spite of these differences, CD4+ T cell epitopes were found only in CDR-sequence containing regions. We were able to incorporate up to two amino acid modifications in a single epitope that reduced the immunogenic potential while retaining full biologic function. We propose that immunogenicity will always be present in some antibody molecules due to the nature of the antigen-specific combining sites. A consequence of this result is modifications to reduce immunogenicity will be centered on the affinity-determining regions. Modifications to CDR regions can be designed that reduce the immunogenic potential while maintaining the bioactivity of the antibody molecule.     

The immunogenicity of humanized and fully human antibodies: Residual immunogenicity resides in the CDR regions

Monoclonal antibodies represent an attractive therapeutic tool as they are highly specific for their targets, convey effector functions and enjoy robust manufacturing procedures. Humanization of murine monoclonal antibodies has vastly improved their in vivo tolerability. Humanization, the replacement of mouse constant regions and V framework regions for human sequences, results in a significantly less immunogenic product. However, some humanized and even fully human sequence-derived antibody molecules still carry immunological risk. to more fully understand the immunologic potential of humanized and human antibodies, we analyzed CD4⁺ helper T cell epitopes in a set of eight humanized antibodies. the antibodies studied represented a number of different VH and VL family members carrying unique CDR regions. In spite of these differences, CD4⁺ T cell epitopes were found only in CDR-sequence containing regions. We were able to incorporate up to two amino acid modifications in a single epitope that reduced the immunogenic potential while retaining full biologic function. We propose that immunogenicity will always be present in some antibody molecules due to the nature of the antigen-specific combining sites. A consequence of this result is modifications to reduce immunogenicity will be centered on the affinity-determining regions. Modifications to CDR regions can be designed that reduce the immunogenic potential while maintaining the bioactivity of the antibody molecule.Key words: therapeutic, antibody, immunogenicity, deimmunizing, epitope     

Humanization of Murine Monoclonal anti-hTNF Antibody: The F10 Story

Tumor necrosis factor (TNF) is a proinflammatory cytokine implicated in pathogenesis of multiple autoimmune and inflammatory diseases. Anti-TNF therapy has revolutionized the therapeutic paradigms of autoimmune diseases and became one of the most successful examples of the clinical use of monoclonal antibodies. Currently, anti-TNF therapy is used by millions of patients worldwide. At the moment, fully human anti-TNF antibody Adalimumab is the best-selling anti-cytokine drug in the world. Here, we present a story about a highly potent anti-TNF monoclonal antibody initially characterized more than 20 years ago and further developed into chimeric and humanized versions. We present comparative analysis of this antibody with Infliximab and Adalimumab.