Monoclonal antibodies directed against the influenza A virus are described, which have the advantageous and unpredicted property of being able to bind a plurality of subtypes of the influenza A virus. One preferred embodiment is the antibody designated as Fab28, which displays a neutralizing activity against a plurality of subtypes of the influenza A virus. Anti-idiotype antibodies directed against the monoclonal antibodies of the invention, immunogenic or vaccine compositions comprising the monoclonal antibodies of the invention are also described, as well as therapeutic, prophylactic and diagnostic applications for the monoclonal antibodies of the invention. The monoclonal antibodies of the invention can also be used for testing antibody preparations to be used as vaccines.
