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目的:针对猫对新型冠状病毒（SARS-CoV-2）的高度易感性，筛选猫主要组织相容性复合物I类（major histocompatibility complex class I，MHC I）分子FLA-K*00701呈递SARS-CoV-2来源的多肽，并探索复合物制备方法，为研究猫感染SARS-CoV-2的T细胞免疫特征打下基础。方法:对可能与FLA-K*00701具有亲和力的SARS-CoV-2来源多肽进行预测并合成。采用稀释复性法，使猫白细胞抗原（feline leukocyte antigen，FLA）I类多肽复合物在体外合适环境下复性，纯化复合物后，用坐滴蒸汽扩散技术筛选晶体的生长条件，X射线衍射区分收集的蛋白结晶是否为晶体。结果:成功筛选到一条与FLA-K*00701具有高度结合能力的SARS-CoV-2来源多肽，并得到高纯度FLA-K*00701蛋白，初步筛选得到FLA多肽复合物晶体，X射线衍射分辨率为2.7?。结论:首次在SARS-CoV-2易感动物猫中筛选到与其FLA I具有高度亲和力的多肽，并得到高分辨率的复合物蛋白晶体，本研究为进一步探索猫抵抗SARS-CoV-2的细胞免疫机制及SARS-CoV-2多肽疫苗的研发提供有价值的参考。“,”Objective:Based on high susceptibility of cat to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), to screen the peptides derived from SARS-CoV-2 and presented by feline major histocompatibility complex class I (MHC I) molecule, FLA-K*00701. And to explore the preparation method of the complex, so as to lay a foundation for the study of T cell immune characteristics of cats infected with SARS-CoV-2.Methods:The peptides derived from SARS-CoV-2 with potential affinity to FLA-K*00701 were predicted and synthesized. The feline leukocyte antigen (FLA) class I polypeptide complex was renatured in a suitable environment n in vitro by the gradual dilution method. After the complex was purified, the crystal growth conditions were screened using the sitting-drop vapor diffusion technique. X-ray diffraction was used to distinguish the quality of collected protein crystal.n Results:A SARS-CoV-2-derived peptide with high binding ability to FLA-K*00701 was successfully screened out, and a FLA-K*00701 protein with high purity was obtained. The crystal of FLA polypeptide complex was obtained by preliminary screening, and the X-ray diffraction resolution was 2.7?.Conclusions:This is the first report of isolating polypeptide with high affinity to FLA I from cat which was susceptible to SARS-CoV-2, and obtaining crystal of the complex with high resolution. The study provided a valuable reference for further research on the cellular immune mechanism of cat against SARS-CoV-2 and for SARS-CoV-2 peptide vaccine development.