Adaptation and attenuation of fowl adenovirus in Vero cells.

摘要

Highly pathogenic Fowl Adenoviruses (FAdVs) have been recognised as primary pathogens of inclusion body hepatitis (IBH) in many poultry producing areas and thus there is a need to develop a vaccine for its control and prevention. Adaptation and attenuation of FAdV (UPM1137) isolated from chickens with IBH in Vero cells is described. Confluent monolayer of Vero cells was inoculated with 0.1 mL FAdV inoculum and monitored daily for 7 days for cytopathic effects. Cytopathic effects were recorded on day 6 from the 1st to 5th passage. Cytopathic damage was induced by FAdV as shown by PCR and sequence analysis. The virus adapted and attenuated up to passage 5 in the presence of nucleotide and amino acid changes in the L2 loop variable region. Amino acids changes occurred at position 506, 512, region between 513 to 514, 521 and 530 (numbering with reference to HAV-2). Phylogenetic trees revealed all samples from the original homogenate embryo liver (P0), first passage (P1) and fifth passage (P5) infected Vero cells were classified under FAdV group E strain.