Preparation of a polyclonal antibody against the non-structural protein, NSs of SFTSV

Severe fever with thrombocytopenia syndrome virus (SFTSV) is newly discovered virus which is the member of the order Bunyavirales, family phenuiviridae, phlebovirus genus. Its genome is composed of 3 segments of negative-sense RNA L, M and S. NSs is a non structure protein encoded by S segment which is important for viral replication and virulence. NSs protein of SFTSV is only involved in the regulation of host innate immune responses and suppression of IFN-promoter activities. So, the exact functions of this protein need to be studied deeply. To understand the exact role of NSs from SFTSV in viral replication and host immune response, a qualified antibody against this protein is required. In this study, NSs gene of SFTSV, was cloned into a bacterial expression vector (pGEX-6P-1) and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) cells. The SFTSV NSs fusion protein was purified using Glutathione Sepharose 4B and utilized as an antigen to immunize rabbits and obtain an anti-SFTSV NSs polyclonal antibody. Proper expression of the fusion protein and polyclonal antibody specificity were confirmed by western blotting and immunofluorescence analyses. The polyclonal antibody recognized NSs from SFTSV specifically. This is the first report that NSs can form viroplasm-like structures not only in infected cells but also in transfected cells with NSs plasmids. This polyclonal antibody will be useful for future studies of NSs functions.