Pseudorabies virus(PRV)early protein UL31 is a homologue of herpes simplex virus 1(HSV-1)UL31,which is a multifunctional protein and important for HSV-1 infection.However,the precise roles of PRV UL31 in virus life cycle are still poorly understood.A relatively crucial tool for uncovering the function of UL31 is an antiserum specifically detects UL31 in the PRV-infected cells.For this purpose,a recombinant truncated UL31 protein consisting of N-terminal 27 aa of UL31 fused to EYFP and His-tag was expressed,purified and used for the preparation of antiserum.Western blot analysis and immunofluorescent assay showed that this antiserum specifically detected purified truncated UL31 as well as full-length UL31 in the PRV infected cells.These results demonstrate that the prepared antiserum could serve as a valuable tool for further studies of UL31 functions.