Recombinant baculovirus-expressed rotavirus protein (VP4) in an ELISPOT assay of antibody secretion

Studies on the protein specificity of the intestinal antibody response to rotavirus infection have been hampered by lack of antigenically conserved isolated proteins to serve as antigens in immunochemical assays. In this report, the use of an antigenically conserved baculovirus-expressed rotavirus protein (VP4) as a capture antigen in the ELISPOT assay is described. Anti- VP4 antibody-secreting hybridoma cells are used as a test population to show that expressed VP4 as the capture antigen detects numbers of antibody secreting cells comparable to intact rotavirus particles. Hybridoma cells specific for other rotavirus proteins are used to ensure the specificity of the expressed VP4 in the assay. The flexibility and ease of use of a recombinant expressed protein product as a capture antigen in this assay dramatically enhances the ability to quantitate intestinal antibody responses to specific viral proteins.