中国农业科学 ›› 2026, Vol. 59 ›› Issue (1): 220-232.doi: 10.3864/j.issn.0578-1752.2026.01.016

• 畜牧·兽医 • 上一篇    

猪轮状病毒VP4单克隆抗体的制备及抗原表位鉴定

赵佳莉1,2(), 卞贤宇1,2, 宋家鹏2, 王晨2, 汤学超2, 李运川2, 周金柱2, 朱雪蛟2, 陶然2, 董海龙1,*(), 张雪寒1,2,*(), 李彬1,2   

  1. 1 西藏农牧大学动物科学学院,西藏林芝 860000
    2 江苏省农业科学院兽医研究所/农业农村部兽用生物制品工程技术重点实验室,南京 210014
  • 收稿日期:2025-05-09 接受日期:2025-07-30 出版日期:2026-01-01 发布日期:2026-01-07
  • 通信作者:
    董海龙,E-mail:
    张雪寒,E-mail:
  • 联系方式: 赵佳莉,E-mail:2517357147@qq.com。
  • 基金资助:
    国家重点研发计划(2023YFD1800502); 国家重点研发计划(1029); 国家自然科学基金(32573401)

Preparation of Monoclonal Antibody to Porcine Rotavirus VP4 and Preliminary Characterization of Antigenic Epitope

ZHAO JiaLi1,2(), BIAN XianYu1,2, SONG JiaPeng2, WANG Chen2, TANG XueChao2, LI YunChuan2, ZHOU JinZhu2, ZHU XueJiao2, TAO Ran2, DONG HaiLong1,*(), ZHANG XueHan1,2,*(), LI Bin1,2   

  1. 1 College of Animal Science, Xizang Agriculture and Animal Husbandry University, Linzhi 860000, Xizang
    2 Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences/Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture and Rural Affairs, Nanjing 210014
  • Received:2025-05-09 Accepted:2025-07-30 Published:2026-01-01 Online:2026-01-07

摘要:

【背景】猪轮状病毒(porcine rotavirus, PoRV)是导致新生仔猪及幼龄仔猪病毒性腹泻的关键病原体之一,其感染可引发宿主严重的胃肠道功能紊乱,临床表现为脱水、腹泻甚至死亡,对全球养猪业造成巨大经济损失。VP4蛋白是PoRV病毒粒子表面关键的结构蛋白之一。VP4蛋白经胰蛋白酶水解后可生成VP8和VP5两个功能亚基,它们在病毒感染宿主细胞的初始阶段发挥核心作用,介导病毒吸附宿主细胞受体和随后的膜穿透过程。同时,VP4蛋白也是激发宿主免疫反应的重要靶抗原。然而,目前针对PoRV VP4蛋白的特异性单克隆抗体(monoclonal antibody, mAb)研究相对匮乏,限制了相关诊断方法和新型疫苗的研发。【目的】制备针对PoRV VP4蛋白的mAb,在此基础上,对这些单克隆抗体进行全面的生物学特性分析,包括反应性、抗原表位类型(构象依赖型或线性)、亚型鉴定以及关键的中和活性评估,精确鉴定VP4蛋白上具有重要功能意义的抗原表位区域,为PoRV感染的精准诊断和新型疫苗设计提供支撑。【方法】以纯化的VP4*P23重组蛋白免疫BALB/c小鼠,运用脾细胞融合技术筛选杂交瘤细胞株,通过Western blot、间接免疫荧光(IFA)、免疫过氧化物酶单层试验(IPMA)鉴定单克隆抗体反应性,采用间接ELISA评估单抗对构象的敏感性。最后构建VP5蛋白的不同截短体鉴定靶向的抗原表位区域,通过体外中和实验评估VP5单抗的中和能力。【结果】成功获得26株稳定分泌抗体的杂交瘤细胞株,抗体亚型包括IgG1、IgG2a、IgG2b和IgM等多种亚型,其中轻链类型以κ链为主。在获得的26株单抗中,有15株被证实能够与天然的PoRV病毒粒子发生特异性反应(通过IFA和IPMA检测)。间接 ELISA检测显示,mAb11、14、15、23 为构象不敏感型单抗,mAb16、17、18、19、21、24、25、26为构象敏感型单抗,值得注意的是,mAb1、2、22这3株单抗在抗原变性后反应性反而增强。Western blot分析进一步聚焦于识别线性表位的单抗(mAb11, 14, 15),结果显示它们均能特异性识别VP5蛋白上约300—360位氨基酸区域内的线性表位,可能针对同一抗原表位。然而,体外中和试验评估表明这3株单抗对PoRV毒株无中和作用。【结论】成功制备多株靶向PoRV VP4蛋白的单克隆抗体,并鉴定了它们与天然病毒结合的能力。通过系统的表征,不仅明确了单抗的亚型分布和轻链类型,更重要的是对单抗的抗原识别特性进行了深入解析:成功区分了构象敏感型与构象不敏感型单抗,并精确定位了mAb11、14、15识别的线性抗原表位区域。研究成果为PoRV 诊断试剂优化、亚单位疫苗研发提供了关键抗体资源,为深入研究VP4蛋白的免疫学功能及抗病毒机制奠定了基础。

关键词: 猪轮状病毒, VP4蛋白, 单克隆抗体, 抗原表位, 诊断

Abstract:

【Background】Porcine Rotavirus (PoRV) is one of the key pathogens causing viral diarrhea in newborn and young piglets, and its infection can lead to severe gastrointestinal dysfunction in the host, with clinical manifestations, including dehydration, diarrhea, and even death, resulting in huge economic losses to the global pig industry. The VP4 protein is one of the key structural proteins on the surface of PoRV virions. The VP4 protein is cleaved by trypsin to generate two functional subunits, such as VP8 and VP5, which play a core role in the initial stage of viral infection of host cells, mediating the adsorption of the virus to host cell receptors and the subsequent membrane penetration process. Meanwhile, the VP4 protein is also an important target antigen that elicits the host immune response. However, current research on specific monoclonal antibodies (mAbs) against the PoRV VP4 protein is relatively scarce, which limits the development of related diagnostic methods and new vaccines. 【Objective】This study aimed to prepare specific monoclonal antibodies (mAbs) against the VP4 protein of Porcine Rotavirus (PoRV), and on this basis, comprehensive biological characterization of these mAbs were analyzed, including reactivity, antigenic epitope types (conformational or linear), and subtype identification, and key neutralizing activities were evaluated too. The aim was to precisely identify the antigenic epitope regions with important functional significance on the VP4 protein, thereby providing support for the accurate diagnosis of PoRV infection and the design of novel vaccines. 【Method】BALB/c mice were immunized with purified VP4*P23 recombinant protein, and hybridoma cell lines were screened using splenocyte fusion technology. The reactivity of monoclonal antibodies was identified by Western blot, indirect immunofluorescence assay (IFA), and immunoperoxidase monolayer assay (IPMA). The conformational sensitivity of monoclonal antibodies was evaluated by indirect ELISA. VP5 truncated proteins were constructed to determine the antigenic epitope regions, and the neutralizing ability of VP5 monoclonal antibodies was assessed by in vitro neutralization assay. 【Result】A total of 26 hybridoma cell lines stably secreting antibodies were successfully obtained. The antibody subtypes included multiple types such as IgG1, IgG2a, IgG2b and IgM, among which the light chain type was mainly κ chain. Among the obtained 26 mAbs, 15 of them were confirmed to specifically react with natural PoRV virions (detected by IFA and IPMA). Indirect ELISA detection showed that mAb11, 14, 15 and 23 were conformation-insensitive mAbs, while mAb16, 17, 18, 19, 21, 24, 25 and 26 were conformation-sensitive mAbs. It was worth noting that the reactivity of three mAbs (mAb1, 2 and 22) was enhanced after antigen denaturation. Western blot analysis further focused on mAbs recognizing linear epitopes (mAb11, 14, 15), and the results showed that they could all specifically recognize the linear epitope within the amino acid region of about 300-360 on the VP5 protein, possibly targeting the same antigenic epitope. However, in vitro neutralization assay evaluation showed that these three mAbs had no neutralizing effect on PoRV strains. 【Conclusion】Multiple mAbs targeting the PoRV VP4 protein were successfully prepared, among which 15 mAbs exhibited the ability to bind to natural viruses. Through systematic characterization, not only the subtype distribution and light chain type of mAbs were clarified, but more importantly, the antigen recognition characteristics of mAbs were deeply analyzed: conformation-sensitive and conformation-insensitive mAbs were successfully distinguished, and the linear antigenic epitope regions recognized by mAb11, 14, and 15 were precisely located. This study provided key antibody resources for the optimization of PoRV diagnostic reagents and the development of subunit vaccines, and laid a foundation for in-depth research on the immunological functions and antiviral mechanisms of the VP4 protein.

Key words: porcine rotavirus, VP4 protein, monoclonal antibody, antigenic epitope, diagnosis