Infection with a new porcine respiratory coronavirus in Denmark: serologic differentiation from transmissible gastroenteritis virus using monoclonal antibodies.

In 1984 neutralizing antibodies against transmissible gastroenteritis virus (TGEV) were detected in pig herds in a small geographical area in the southern part of Denmark. No clinical symptoms were observed and accumulating epidemiological evidence gradually pointed towards a respiratory infection. In 1986 a TGE-like virus, tentatively named porcine respiratory coronavirus (PRCV), was isolated from the lungs of swine. The virus was partially characterized using monoclonal antibodies against TGEV and this showed that some (mainly nonneutralizing) epitopes of the peplomer glycoprotein E2 were absent in PRCV, whereas the major neutralizing domains were conserved. These findings allowed the design of competitive antibody immunoassays either discriminating or not discriminating the immune responses against the two viruses. However, the discriminating epitopes studied so far have shown minor immunodominance and some steric interference from nondiscriminating epitopes.