Group A rotavirus infections are the most common cause of severe gastroenteritis among infants and young children world-wide. Several rotavirus candidate vaccines have been evaluated for efficacy in clinical trials with variable success. Rotavirus surface proteins VP4 and VP7 have been shown to be independent protective antigens. Recently, in studies by others in a mouse model, (i) certain IgA monoclonal antibodies directed to rotavirus inner capsid protein VP6 were reported to be protective against disease, and (ii) antibodies directed to rotavirus nonstructural protein NSP4 (viral entertoxin) were shown to be effective passively in protection against disease. More recently, an immunohistochemistry assay was developed, in which Sf-9 cells infected with recombinant baculovirus that expresses specific rotavirus protein as an antigen was utilized to assess immune response. In order to establish an immunohistochemistry assay in our laboratory for assessment of immune response to selected rotavirus proteins following natural rotavirus infection or vaccination, we constructed cDNA clones representing the VP4 gene of rhesus rotavirus (RRV) strain MMU18006 and the NSP4 gene of RRV or human rotavirus strain Wa, and inserted each into a baculovirus expression vector. The resulting recombinant expressed the appropriate authentic RRV VP4 protein or NSP4 protein of RRV or Wa as confirmed by immunohistochemistry assay and/or Western blotting.
