Using monoclonal antibodies against the common epitopes of NSs proteins for the prompt detection and differentiation of tospoviruses prevalent in Euro-America and Asia Regions

Virus species in the genus Tospovirus can be classified into serogroups based on the serology of nucleocapsid protein, one of the key criteria for the identification of a tospovirus. Most globally important tospoviruses belong to the serogroups containing Tomato spotted wilt virus (TSWV), Watermelon silver mottle virus (WSMoV) and Iris yellow spot virus (IYSV) as type species. In this investigation, we attempted to develop a generic monoclonal antibody (MAb) against the common epitopes of the NSs proteins of TSWV and Impatiens necrotic spot virus (INSV), two representative tospoviruses prevalent in Europe and America. The NSs proteins of TSWV and INSV were individually expressed in the bacterial pET system, and the purified recombinant proteins, denoted TNSs and INSs, respectively, were used to produce MAbs. Results from indirect enzyme-linked immunosorbent assays (ELISAs) and western blotting indicated that the selected MAb-INSs-55G4E7 against INSs broadly reacts with the NSs proteins of INSV, Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV), two members of the TSWV serogroup. All obtained MAbs against TNSs are TSWV specific. Our results indicate that the combination of MAb-INSs-55G4E7 and TSWV-specific MAb-TNSs-81D9E2 reacted with four tested Euro-America-type tospoviruses. Remarkably, the three-in-one combination of MAb-INSs-55G4E7, MAb-TNSs-81D9E2 and the previously prepared MAb-WNSs, which reacts with the common epitope of the NSs proteins of Asia type tospoviruses, reacts with all 12 tested tospoviruses from different geographic regions. Here, we report an efficient serological tool for the prompt detection and differentiation of the most economically important tospoviruses prevalent in Europe, America and Asia.