Foot-and-mouth disease (FMD) is a highly contagious infection caused by foot-and-mouth disease virus (FMDV). Exosomes are extracellular vesicles that mediate antiviral immune responses in host cells and could be used by pathogens to evade host cell immune responses. Whether FMDV affects exosome secretion or whether exosomes derived from FMDV-infected cells mediate host cell antiviral immune responses is not yet clarified. In this study, the exosomes were identified and extracted from FMDV-infected PK-15 cells, and it was found that FMDV inhibits exosome secretion. Further investigation revealed that FMDV suppresses exosomes by degrading Rab27a via the autophagy-lysosome pathway. Also, microRNA (miRNA) differential analysis was performed in exosomes, which revealed that miRNA-136 was highly differentially expressed in exosomes and may be the key miRNA that inhibits the proliferation of FMDV. In summary, these results showed that host cells take advantage of exosomes to mediate their antiviral immune response, while FMDV evades exosome-mediated immune responses by degrading the exosome molecular switch, Rab27a.

口蹄疫（FMD）是一种由口蹄疫病毒（FMDV）引起的高度传染性感染。外来体是介导宿主细胞中抗病毒免疫反应的细胞外囊泡，病原体可以利用它们来逃避宿主细胞的免疫反应。FMDV是否会影响外泌体分泌或源自FMDV感染的细胞的外泌体是否介导宿主细胞抗病毒免疫应答。在这项研究中，从FMDV感染的PK-15细胞中鉴定并提取了外泌体，发现FMDV抑制外泌体分泌。进一步的研究表明，FMDV通过自噬溶酶体途径降解Rab27a来抑制外来体。此外，在外泌体中进行了microRNA（miRNA）差异分析，这表明miRNA-136在外泌体中高度差异表达，可能是抑制FMDV增殖的关键miRNA。总之，这些结果表明宿主细胞利用外泌体介导其抗病毒免疫反应，而FMDV通过降解外泌体分子开关Rab27a逃避了外泌体介导的免疫反应。