Simultaneous Detection of Antibodies to Mouse Hepatitis Virus Recombinant Structural Proteins by a Microsphere-Based Multiplex Fluorescence Immunoassay ᰔ Downloaded from Abstract We describe a new microsphere-based multiplex fluorescent immunoassay (MFI) using recombinant mouse hepatitis virus (MHV) proteins to detect antibodies to coronaviruses in mouse and rat sera. All the recombinant proteins, including nucleocapsi