Abstract
Enzyme-linked immunosorbent assay (ELISA) using B42 strain of infectious bronchitis virus (IBV) as an antigen was developed for detection of antibodies against IBV. Purified IBV solubilized with Triton X-100 served as the antigen. Although there was little cross-reactivity in the serum neutralization (SN) test, cross-reactivity was observed among IBV strains B42, Gray, and A5968 (Massachusetts, Delaware, and Connecticut serotypes, respectively). In addition, B42 strain reacted also with antisera against three other serotype strains (Iowa97, Iowa609, and M41) and those against six strains isolated in Japan (distinguishable from each other by the SN test) in ELISA. Thus a wide range of cross-reaction was observed with B42 strain of IBV. Corrected ELISA (cELISA) values of serum samples of chickens naturally infected with IBV in the field did not correlate with thier SN titers. Those of chikens experimentally infected with a single strain of IBV (B42), however, increased with the rise of the SN titer. Therefore, our ELISA system seems to show an IBV-specific reaction. These results suggest that antibodies to several subtypes of IBV can be detected with only one type of virus as an ELISA antigen. The ELISA technique appears to be suitable for large-scale serological surveys and rapid and simple to perform.
