CHARACTERIZATION OF MONOCLONAL-ANTIBODIES TO BOVINE ENTERIC CORONAVIRUS AND ANTIGENIC VARIABILITY AMONG QUEBEC ISOLATES

Twenty monoclonal antibodies (MAbs) were prepared against the Mebus st rain of bovine enteric coronavirus, 14 of them reacting with the peplo meric S (gp 100) glycoprotein. Competition binding assays allowed the definition of at least 4 distinct antigenic domains for the S glycopro tein, designated as A, B, C, and D; epitopes associated to neutralizin g activity being located in sites A, B, and C. One MAb directed to the hemagglutinin HE (gp 140/gp 65) glycoprotein inhibited the hemaggluti nating activity of the virus, but had no neutralizing activity. Compar ison of Quebec enteropathogenic BCV isolates using polyclonal antiseru m and MAbs directed to the S glycoprotein confirmed their close antige nic relationship, but also revealed the occurrence of at least three d istinct antigenic subgroups. Antigenic domain D was highly conserved a mong BCV isolates, as well as non-neutralizing epitopes assigned to an tigenic domains A and C. The Minnesota strain of turkey enteric corona virus could be distinguished from BCV isolates by MAbs directed to epi topes of antigenic domain C, whereas human coronavirus HCV-OC 43 could be distinguished by MAbs directed to epitopes of antigenic domain A. The porcine hemagglutinating encephalomyelitis virus could be distingu ished from the other hemagglutinating coronaviruses by neutralizing ep itopes located on antigenic domains A, B, and C.