畜牧兽医学报 ›› 2024, Vol. 55 ›› Issue (7): 3132-3142.doi: 10.11843/j.issn.0366-6964.2024.07.031

• 基础兽医 • 上一篇    下一篇

MHCⅠ类分子BF2*0201递呈ALV-J表位结构和递呈机制解析

贾玉生(), 李易霖, 马露露, 廖明, 代曼曼*()   

  1. 华南农业大学兽医学院,人兽共患病防控制剂国家地方联合工程实验室,广东省动物源性人兽共患病预防与控制重点实验室,广州 510642
  • 收稿日期:2023-10-19 出版日期:2024-07-23 发布日期:2024-07-24
  • 通讯作者: 代曼曼 E-mail:jiayusheng0922@163.com;daimanman1229@scau.edu.cn
  • 作者简介:贾玉生(1999-),男,河南南阳人,硕士生,主要从事家禽抗病毒免疫应答研究,E-mail: jiayusheng0922@163.com
  • 基金资助:
    国家自然科学基金面上项目(32172868);高等学校学科创新引智计划项目(D20008)

Structure and Mechanism of ALV-J Epitope Presented by MHC Class Ⅰ Molecule BF2*0201

Yusheng JIA(), Yilin LI, Lulu MA, Ming LIAO, Manman DAI*()   

  1. National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
  • Received:2023-10-19 Online:2024-07-23 Published:2024-07-24
  • Contact: Manman DAI E-mail:jiayusheng0922@163.com;daimanman1229@scau.edu.cn

摘要:

MHC B2单倍型鸡对禽白血病病毒感染有较强抗性,这种抗病性可能与被MHC分子递呈的表位刺激活化的T细胞产生的免疫应答有关。本研究拟阐明MHC Ⅰ类分子BF2*0201递呈ALV-J表位结构和递呈机制。利用凝胶过滤层析筛选出能与MHC Ⅰ稳定结合的肽。利用晶体初筛试剂盒在体外培育肽和MHC Ⅰ的二元复合物晶体,并利用COOT、CCP4和PYMOL等软件对该晶体结构进行解析和分析。在这项研究中,作者发现二个与BF2*0201稳定结合的ALV-J CTL表位FVDFANRLI和SALQAFREV。得到一个优质晶体BF2*0201-SALQAFREV(SV9),其生长条件为1.0 mol ·L-1 丁二酸(pH 7.0),0.1 mol ·L-1 HEPES (pH 7.0),1%聚乙二醇单甲醚2000。解析高分辨率(1.72 Å)的BF2*0201-SV9复合物结构后发现BF2*0201抗原结合槽整体呈现弱负电性。保守的残基多位于抗原结合槽的两端,特异性氨基酸赋予BF2*0201中等大小的抗原结合槽。B、C和F口袋起着较重要的锚定作用,口袋残基和水分子与抗原多肽形成氢键作用,将其固定在抗原结合槽中。SV9表位构象中突出的P4-Gln和P7-Arg残基的构象特征表明该位点有被特异性TCR潜在识别的特性。BF2*0201-SV9复合物晶体结构特征有助于阐明B2单倍型MHCⅠ类分子BF2*0201递呈ALV-J表位的机制,有助于解释B2单倍型鸡对ALV存在抗性的原因,为抗病育种工作奠定理论基础。

关键词: MHC, BF2*0201, ALV-J, 递呈机制, 晶体结构

Abstract:

MHC B2 haplotype chickens are highly resistant to avian leukosis virus infection, and this resistance may be related to the activated T cell immune response stimulated by MHC molecule presented epitopes. This study aims to elucidate the structure and mechanism of ALV-J epitope presentation by the MHC class Ⅰ molecule BF2*0201. Peptides that can bind stably to MHC Ⅰ were screened by gel filtration chromatography. The complex crystals of the peptide and MHC Ⅰ were grown in vitro using a crystal primary screening kit, and the crystal structure was resolved and analyzed using COOT, CCP4 and PYMOL. In this study, we identified two ALV-J CTL epitopes FVDFANRLI and SALQAFREV that bind stably to BF2*0201. We obtained a high quality crystal BF2*0201-SALQAFREV (SV9) grown under the conditions of 1.0 mol ·L-1 succinic acid (pH 7.0), 0.1 mol ·L-1 HEPES (pH 7.0), and 1% polyethylene glycol monomethyl ether 2000. We resolved the structure of the high-resolution (1.72 Å) BF2*0201-SV9 complex and found that the BF2*0201 antigen-binding groove exhibits weak electronegativity overall. Conserved residues were located at both ends of the antigen-binding groove, and specific amino acids gave BF2*0201 a medium-sized peptide-binding groove. The B, C, and F pockets played an important anchoring role. The residues in pockets and water molecules formed hydrogen bonds with the antigenic polypeptide to anchor it to the peptide-binding groove, and the antigenic polypeptide was in an "M"-shaped conformation. The conformational features of the prominent Gln-4 and Arg-7 residues in the SV9 epitope conformation suggested potential recognition of this site by specific TCRs. The crystal structure of BF2*0201-SV9 complex can help to elucidate the mechanism of ALV-J epitope presented by BF2*0201, which can help to explain the reason for the resistance of B2 haplotype chickens to ALV, and lay a theoretical foundation for the breeding of resistance to the disease.

Key words: MHC, BF2*0201, ALV-J, epitope presentation, crystal structure

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