Molecular Classification of Infectious Laryngotracheitis Virus from Chick Embryo Origin Vaccine, Tissue Culture Origin Vaccine and Field Isolates

Abstract

The molecular classification of the infectious laryngotracheitis virus from chicken embryo origin (CEO) vaccine, tissue culture origin (TCO) vaccine and field isolates by the sequence of ICP4 genes from CEO and TCO vaccines in the GenBank was performed for the different sequence analysis. The sequences of TCO vaccine virus (accession no. EU104908) were used as a prototype for a primer design to cover the region of 450 basepairs (bp) by
Primer3 software. The simulation sequences of CEO vaccine virus (accession no. EU104900) and TCO vaccine virus (accession no. EU104908) from PCR reaction were selected for restriction enzyme. Hga I could separate 3 isolates of the viruses from simulation model and in vitro model. The PCR products from CEO, TCO and field isolates were 428, 440 and 450 bp, respectively. The PCR products were cut by restriction enzyme, Hga I, and the results revealed the DNA of CEO vaccine virus equal to 414 and 14 bp and TCO vaccine virus equal to 250 and 176 bp. The field virus has no restriction sequences according to Hga I, so no RFLP production occurred and the PCR product remained at 450 bp.