Monoclonal antibodies developed for detection of an epizootic virus associated with mass mortalities of cultured scallop Chlamys farreri

Recently, an enveloped, spherical RNA virus was identified as the causative agent of mass mortalities among adult scallop Chlamys farreri, which is cultured on the northern coast of China. Hybridomas were prepared from mice immunized with highly purified virions. Four stable hybridomas secreting monoclonal antibodies (MAbs) of IgG isotype were obtained after screening by means of enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). The specificity of the MAbs to this virus was confirmed by immunogold electron microscopy (IEM). All the selected MAbs recognized epitopes on the envelope spikes of the virions. Subsequently, the MAbs were used for in situ immunofluorescent detection of the virus in Davidson's fixed tissue sections. The results showed that the fluorescent cells were mostly observed in epithelia of different organs, but not in the epithelium of the digestive diverticulae. Cytopathological changes and focal lesions corresponding to virus-positive cells were clearly recognized in the affected epithelia, revealing a potential role of this virus in pathogenesis.