I7L蛋白对非洲猪瘟病毒适应野猪肺泡巨噬细胞系的调控作用及其机制

缺乏支持非洲猪瘟病毒（ASFV）复制的传代细胞系是长期制约其研究的技术瓶颈。本团队前期构建了一株永生化野猪肺泡巨噬细胞系，ASFV中国流行株在该细胞系上连续传30代后能够稳定增殖并产生明显的细胞病变，然而其适应机制未知。与亲本毒株相比，ASFV传代细胞适应株的右侧可变区I7L基因发生缺失；无独有偶，已报道的Vero细胞适应株ASFV-G/V30和BA71V的I7L基因也发生缺失。我们推测，I7L蛋白在ASFV适应传代细胞过程中可能发挥拮抗作用。本项目利用基因编辑技术构建I7L基因缺失的重组病毒，验证I7L蛋白在ASFV适应传代细胞过程中的调控作用；其次，通过生物信息学及体内外生物学分析，明确I7L蛋白在ASFV复制周期中的功能；最后，利用病毒与宿主相互作用平台解析I7L蛋白调控ASFV适应传代细胞的分子机制。本研究可望揭示ASFV的细胞适应机制，为快速构建支持ASFV复制的细胞系提供依据。

The lack of a stable cell line supporting the replication of African swine fever virus (ASFV) is a major technical bottleneck restricting the progress of ASFV study. Recently, our group has developed an immortalized cell line derived from wild boar alveolar macrophages (WBAM-18). The Chinese epidemic ASFV strain ASFV/HLJ-18 was successively passaged for 30 times in WBAM-18 cells, resulting in a cell-adapted strain, ASFV/HLJ-18-V30, which can stably replicate and produce obvious cytopathic effects in the cells. However, the cell adaptation mechanism of ASFV remains elusive. Compared to the ASFV/HLJ-18 strain, the ASFV/HLJ-18-V30 shows a deletion of the I7L gene in the right variable region. Coincidentally, for ASFV-G/V30 and BA71V, previously reported Vero cells-adapted ASFV strains, their I7L genes also show the same deletions. We speculate that the I7L protein may have restricting effects on the ASFV adaptation to WBAM-18 cells. In this proposal, we will investigate the regulatory roles of the I7L protein in the ASFV adaptation to WBAM-18 cells through constructing the I7L-deleted virus using the established ASFV genetic manipulation platform. Secondly, we will clarify the functions of the I7L protein in the virus life cycle of ASFV by bioinformatic analysis and biological characterization in vitro and in vivo. Finally, we will elucidate the molecular mechanism of I7L regulating the ASFV adaptation to WBAM-18 cells based on virus-host interactions. This project is expected to uncover the cell adaptation mechanism of ASFV, which will provide insights into the rapid development of stable lines supporting ASFV propagation.