ANTIGENIC CHARACTERIZATION OF HANTAAN AND SEOUL VIRUS NUCLEOCAPSID PROTEINS EXPRESSED BY RECOMBINANT BACULOVIRUS - APPLICATION OF A TRUNCATED PROTEIN, LACKING AN ANTIGENIC REGION COMMON TO THE 2 VIRUSES, AS A SEROTYPING ANTIGEN

Hantaan virus (HTN) and Seoul virus (SEO) are members of the genus Han tavirus in the family Bunyaviridae and are causative agents of hemorrh agic fever with renal syndrome. The complete and truncated nucleocapsi d proteins (NP) of HTN and SEO were expressed by a recombinant baculov irus system, Antigenic characterization of the NP using monoclonal ant ibodies (Mabs)indicated that the binding sites For the serotype-specif ic MAbs were located between amino acids (aa) 155 and 429, a Western b lot assay indicated that the serotype-specific epitopes were conformat ion dependent. An indirect immunofluorescence antibody (IFA) assay wit h the truncated NP (aa 155 to 429) was able to distinguish convalescen t-phase sera from HTN and SEO patients. However, the antibody liters w ith the truncated NP were lower than those with the whole NP, The trun cated NP of SEO (aa 155 to 429) could be used as an enzyme-linked immu nosorbent assay (ELISA) antigen, but the truncated NP from HTN lost it s reactivity when used for ELISA. The LFA assay using baculovirus-expr essed truncated NP as an antigen is a rapid, simple, and safe test for distinguishing between HTN and SEO infections by serotype.