Analysis of concentrated chimeric VLP: (A) Western blot identification of the HA protein using anti-H5 monoclonal antibody. M, standard molecular size marker (EBM-1032, Elpisbio), HA, chimeric VLPs; (B) Western blot identification of the F/HA chimeric protein using anti-NDV F monoclonal antibody; (C) Western blot identification of the M1 protein using anti-H5N1 anti-serum; (D) TEM identification of chimeric VLP with scale bar; (E) immunogold-labelled chimeric VLP: VLP were probed with anti-H5 monoclonal antibody, counterstained with 10nm gold spheres coupled to anti-mouse IgG and anti-NDV anti-serum, counterstained with 25nm gold spheres coupled to anti-chicken IgG.