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

We describe a new monoclonal antibody No. 204 (mcAb 204) which recognized a family of four polypeptides, consisting of a 27kD, a 24/23kD double band and a 19kD protein present within PEDV infected cell lysates. These proteins were identified by immunoprecipitation as well as by staining of immunoblots. In infected Vero cell cultures, the synthesis of the 27kD protein was initiated between 6 and 8 hours post inoculation. The 24/23kD double band and the 19kD protein were only detectable later. At least the 27 and the 24/23kD proteins were apparently glycosylated and present in purified virions. Pulse-chase as well as solubilization experiments indicated that the faster migrating bands represented processed products of the 27kD glycoprotein. The nature of the processing is not known at present. We suggest that the 27kD protein family may represent the integral membrane protein M of PEDV. Since this protein is highly abundant in virions as well as in infected cells, and since mcAb 204 is able to react with its antigen under various conditions, this monoclonal antibody may be useful to further studies of the M-protein of PEDV. In addition, it may provide a useful tool for routine diagnosis.