Abstract: A method for prophylaxis of infection of the respiratory tract of a subject by pathogenic airborne bacteria the method comprising administering to the subject by inhalation binding proteins directed against the bacteria. the pathogenic bacteria is a bacteria which survives inside phagocytes and the binding proteins are directed against said bacteria which survives inside phagocytes. The binding proteins comprise antibodies or antibody fragments directed against said bacteria which survives inside phagocytes. The binding proteins are selected from the group consisting of polyclonal antibodies, monoclonal antibodies, F(ab) fragments, F(ab?)2 fragments, antibody tip fragments, chimeric and humanized antibodies and fragments and recombinant antibodies and fragments.