Expression and immune characterization of a novel enzyme, protein arginine methyltransferase 1, from Schistosoma japonicum

Protein arginine methyltransferase 1 (PRMT1) is an arginine-specific protein methyltransferase that methylates a number of proteins involved in transcription and RNA metabolism in all parasitic helminths, including the human blood fluke, Schistosoma japonicum. To characterize the role of PRMT1 in the development of S. japonicum and to investigate its influence on parasite–host interactions, we cloned and expressed the protein from an existing cDNA library. We report that the clone encoded a polypeptide comprising 360 amino acids with a predictive Mr of 42 kDa. Bioinformatic analyses predicted that there were many potential B cell epitopes and T cell epitopes associated with SjcPRMT1, suggesting it is a potential candidate molecule for vaccine development. The purified recombinant protein of S. japonicum (Chinese strain) (rSjcPRMT1) was found to be immunogenic, eliciting a high antibody titer in mice. Moreover, Western blot analysis revealed that the protein could be recognized by the sera of infected mice. Using flow cytometry, we showed that rSjcPRMT1 slightly upregulated the expression of CD40, CD80, CD86, and MHC-II molecules of mouse bone marrow-derived dendritic cell (BMDC), indicating that rSjcPRMT1 could induce mouse BMDC to mature and, therefore, activate their immune response. Overall, our findings provide evidence that rSjcPRMT1 could serve as an effective candidate molecule for the development of a vaccine against infection with S. japonicum.