Protective effects of HN and F glycoprotein-specific monoclonal antibodies on experimental Newcastle disease

Monoclonal antibodies directed against two different epitopes of HN protein of NDV Italien neutralised this virus in both in vitro and in vivo tests. Moreover, the combination of these two HN monoclonal antibodies neutralised the Italien virus synergistically. Five monoclonal antibodies directed against the F protein of NDV had variable neutralising activity against NDV Italien. Passive protection afforded by some anti F monoclonal antibodies was higher than that observed with the combination of the two HN monoclonal antibodies and even equivalent or better than that obtained with rabbit polyclonal antiserum. The importance of the F protein in the immune response against NDV is demonstrated.