MALDI-TOF MS analysis for detection of bovine coronavirus with tryptic peptides from viral proteins.

Bovine coronavirus (BCoV）, a significant cattle pathogen causing enteric and respiratory diseases, is primarily detected using reverse transcription-polymerase chain reaction. Our objective was to develop a novel detection method for BCoV by matrix-assisted laser desorption/ionization‒time-of-flight mass spectrometry (MALDI-TOF MS）. Peptide mass fingerprint analysis revealed that nucleocapsid (N）, membrane (M）, and hemagglutinin-esterase (HE) were three main BCoV proteins. Their tryptic peptides were used as target molecules for BCoV detection. When the tryptic digest of 10 viral copies was analyzed by MALDI-TOF MS, five peptides with relatively strong peaks were detected. The detection limit was between 10 and 10 copies per test for BCoV alone. To detect BCoV in the swab eluate, ultrafiltration purification achieved a detection limit between 10 and 10 copies per test, sufficient to detect BCoV-infected calves. Our findings offer valuable insights for BCoV detection by MALDI-TOF MS.