Detection of Infectious Laryngotracheitis Virus Antibodies by Glycoprotein-Specific ELISAs in Chickens Vaccinated with Viral Vector Vaccines

摘要

Two glycoproteins of infectious laryngotracheitis virus (ILTV), gl and gB, were expressed in baculovirus and purified for the development of ILTV recombinant protein-based ELISAs. The ability of gB and gl ELISAs to detect ILTV antibodies in chickens vaccinated with viral vector vaccines carrying the ILTV gB gene, Vectormune~R FP-LT (the commercial fowlpox vector laryngotracheitis vaccine) and Vectormune~R HVT-LT (commercial turkey herpesvirus vector laryngotracheitis vaccine), was evaluated using serum samples from experimentally vaccinated and challenge chickens. The detection of gB antibodies in the absence of gl antibodies in serum from chickens vaccinated with FP-LT indicated that the gB ELISA was specific for the detection of antibodies elicited by vaccination with this viral vector vaccine. The gB ELISA was more sensitive than the commercial ILTV ELISA to detect seroconversion after vaccination with the FP-LT vaccine. Both gl and gB antibodies were detected in the serum samples collected fromchickens at different times postchallenge, indicating that the combination of these ELISAs was suitable to screen serum samples from chickens vaccinated with either recombinant viral vector FP-LT or HVT-LT vaccines. The agreement between the gl ELISA and the commercial ELISA to detect antibodies in serum samples collected after challenge was robust. However, further validation of these ELISAs needs to be performed with field samples.