engleski

Evaluation of immune status with a competitive nucleic acid hybridization assay for chicken interferons (IFN) alpha and gamma in whole blood

Immune suppression in poultry is a serious problem that is not easily monitored. We have developed a competitive nucleic acid hybridization test for mRNA of chicken IFN alpha and gamma that can be done in microtitre plates. DNA probes for the mRNA were produced with plasmids provided by Drs. J. W. Lowenthal (CSIRO, Australia), and M. J. Sekellick and P. I. Marcus (U. Conn., USA). Sample RNA was allowed to bind to immobilized capture probe and compete with labelled probe added in excess of the capture probe. Signal was inversely proportional with competition by the mRNA. Specific-pathogen-free chickens had no detectable message until 2 hr after immunization with inactivated Newcastle disease vaccine (NDV). Kinetics of the mRNA response were the same for both IFN, and reached maximum level in about 6 hr, declined and rose again, followed by decline to baseline in 7 days. Biphasic response is indicative of paracrine action and has been observed with other cytokines. Response was the same from one day to 4 wk of age, indicating that immune incompetence of the very young is a post-transcriptional event. Chickens were injected intracoelomically with 1, 2.5, and 5 mg cyclophosphamide for 3 days before NDV immunization at 2 wk of age, and samples for IFN mRNA were taken 4 hr later. Levels of mRNA were decreased in dose related fashion, and they correlated with antibody responses one week later. The test can be used for evaluation of immune status of chickens and for research into the molecular events responsible for immune suppression.

Interferon; chicken; mRNA; competitive hybridization

nije evidentirano