Baculovirus expression of turkey coronavirus nucleocapsid protein

The nucleocapsid (N) gene of turkey coronavirus (TCV) was amplified by reve rse transcriptase-polymerase chain reaction, cloned, and expressed in the b aculovirus expression system. A recombinant baculovirus containing the TCV N gene (rBTCV/N) was identified by polymerase chain reaction and expression of TCV N protein as determined by western immunoblot analysis. Two TCV-spe cific proteins, 52 and 43 kDa, were expressed by rBTCV/N; one of these prot eins, p52, was comparable in size to native TCV N protein. Baculovirus-expr essed N proteins were used as antigen in an indirect enzyme-linked immunoso rbent assay (ELISA) for detection of TCV-specific antibodies. The ELISA det ected antibodies specific for TCV and infectious bronchitis virus, a closel y related avian coronavirus, but did not detect antibodies specific for oth er avian viruses (avian influenza, avian reovirus, avian paramyxovirus 3, a vian adenovirus 1, or Newcastle disease virus). These findings indicate tha t baculovirus-expressed TCV N protein is a suitable source of antigen for E LISA-based detection of TCV-specific antibodies in turkeys.