Monoclonal antibody solution hybridization assay for detection of mouse hepatitis virus infection

A monoclonal antibody solution hybridization (MASH) assay was developed to detect fecal excretion of mouse hepatitis virus (MHV). The assay used a biotinylated cDNA probe to detect viral RNA target sequences by hybridization in solution, capture of hybrids on the solid phase with antibiotin antibody, and immunoassay with an enzyme-labelled monoclonal antibody specific for DNA-RNA hybrids. The MASH assay was used to monitor the time course of enterotropic MHV excretion after oronasal inoculation. Infectivity of the inoculated mice was simultaneously monitored with sentinel animals. The MASH assay detected MHV excretion in all inoculated mice, with the highest mean excretion levels occurring from day 3 through day 9 postinoculation. Mean excretion then decreased gradually to below detection limits by day 21 postinoculation. Sentinels became infected on exposure to inoculated mice up to but not after day 21 postinoculation. Infected sentinel mice showed a time course of virus excretion similar to that of inoculated mice. These results indicate that the MASH assay is useful for rapid, sensitive, and specific detection of MHV in clinical specimens from laboratory mice.