A monoclonal antibody-based competitive enzyme-linked immunosorbent assay for detecting antibody production against avian reovirus protein σA

An assay protocol based on a monoclonal antibody-based competitive enzyme-linked immunosorbent assay (MAb-based c-ELISA) for detection of antibody against avian reovirus protein sigma A in chicken is described. After the conditions for MAb-based c-ELISA had been optimized, sera collected from birds that received live and inactivated avian reovirus vaccines in different combinations were tested for antibody response against virus protein sigma A. The results show a high level of antibody against sigma A was in both vaccinated specific pathogenic free (SPF) and vaccinated commercially reared birds as long as one of the vaccines administered was in an inactivated form. The high level of antibody production is indicated by a high percentage inhibition (PI) values in the sera of the birds; but no antibody production was found in birds which received live vaccine only, as indicated by the low PI values. In serum samples from SPF birds receiving vaccines that include an inactivated form of the vaccine, there is a good correlation between the PI values and serum neutralizing antibody (SN) titers. Again, this correlation was not observed in birds that received only live vaccine. The PI values of commercially reared birds receiving inactivated vaccine were significantly different from those of the mock-treated birds, but this was not the case when the birds received only live vaccine. Taken together, the results suggest that MAb-based c-ELISA may provide an alternative choice for determining the immune status of a vaccinated chicken flock as long as one of the vaccines used was inactivated, and thus would allow a more precise way to predict the appropriate time for vaccination. (c) 2006 Elsevier B.V. All rights reserved.