Preliminary characterization of a monoclonal antibody specific for a viral 27 kD glycoprotein family synthesized in porcine epidemic diarrhoea virus infected cells

Immunohistochemical detection of porcine epidemic diarrhea virus compared to other methods

An immunohistochemistry method using formalin-fixed tissues, a direct immunofluorescence method using cryostat sections, an enzyme-linked immunosorbent assay (ELISA), and a PCR method were compared for diagnosis in a litter of weaned pigs that had been experimentally inoculated with wild-type porcine epidemic diarrhea virus (PEDV) and killed between 6 and 60 h after onset of diarrhea. The immunohistochemistry method proved to be as reliable as direct immunofluorescence for diagnosis of PEDV in tissues collected postmortem. The good reliability of ELISA for investigating clinical samples was confirmed, whereas the PCR method used was ineffective.

Identification of the membrane protein of porcine epidemic diarrhea virus

Sequence information on the genome of porcine epidemic diarrhea virus(PEDV) has only recently been determined. In contrast, very little is known about the viral proteins. In the present report we have identified the membrane glycoprotein (M) of PEDV by use of rabbit anti-peptide sera and transient expression of the cloned M gene in Vero cells and by expression in the baculovirus system. The native M protein of PEDV is incorporated into virions, is N-glycosylated, and migrates with a relative mobility (Mr) of 27 k in polyacrylamide gels. In contrast, the M protein synthesized by recombinant baculoviruses migrates with a Mr of 23 k, that is, with identical mobility as the deglycosylated product of PEDV. Thus, it appears that M protein specified by the recombinant baculovirus is poorly, if at all, glycosylated. Using monoclonal antibodies and rabbit and rabbit antipeptide sera specific for the N and C termini of the M protein, we were able to show that a 19 k band detected in PEDV-infected cells but not in virions represented a fragment of M from which the C terminus had been cleaved off. Finally, by electron microscopy and immunogold labelling, the relative orientation of M within the virion envelope was determined as NexoCcyt. In conclusion, all of these data strongly support the hypothesis that PEDV should be classified with the group I coronaviruses.