Fusion inhibitory activity of chicken immune sera.

aVero cells were infected with the indicated recombinant VRPs using an MOI of 5 ffu/cell.
Five hours p.i., HAH5/H1 and HAH1 were proteolytically activated with trypsin. Six hours p.i., the cells were incubated with serial dilutions of the indicated chicken sera or Mab C179, shortly exposed to pH 5.4 and incubated for 2 hours in normal medium prior to fixation. The serum dilution causing 50% inhibition of syncytia formation was calculated. Mean values and standard deviations of three independent experiments are shown.