Fig. 3.

Immunofluorescence assay of serum IgG antibodies against AiV on infected Vero cells. (A) Human serum at 1:400 dilution as the positive control; (B) dog serum sample diluted 1:100; (C) negative control with PBS; (D) cat serum at 1:100 dilution. Vero cells were infected with AiV and further incubated for 8 h. After washing and fixing the cells with methanol:acetone, they were incubated with each serum dilution, washed and IgG antibodies were detected using FITC-labelled appropriate secondary antibodies.