Abstract:[Objective] Exploring the interaction between porcine reproductive and respiratory syndrome virus (PRRSV) nsp11 and host cellular proteins is important for revealing the function of nsp11 in viral replication. [Methods] The host cellular proteins that interact with nsp11 were screened by immunoprecipitation combined tandem mass spectrometry and analyzed by GO annotation, COG annotation as well as KEGG pathway annotation. The screened host cell protein IRAK1 was selected, and then the interaction between nsp11 and IRAK1 was determined by co-immunoprecipitation and confocal microscopy assays. [Results] Compared with the control group, there were 3 differential bands in PRRSV-infected group and 201 host cellular proteins were identified on these differential bands by further LC-MS/MS analysis. These host cellular proteins are closely related to protein metabolism, transduction of cell signaling pathways and pathogenicity of pathogens. Based on the bioinformatics analysis, host cellular protein IRAK1 was identified to interact with the nsp11. [Conclusion] This study identified the host cellular proteins that can interact with PRRSV nsp11, and bioinformatics analysis showed that these proteins play crucial role in virus replication and pathogenesis. The results indicate the direction of the study of nsp11, and also provide a foundation for elucidating the associated molecular mechanisms of the interaction of host cellular proteins with viral proteins in regulating the viral replication and pathogenesis.