H5N1 Virus Attachment to Lower Respiratory Tract.

INFLUENZA viruses; RESPIRATORY organs; ANIMAL species; AVIAN influenza; PNEUMONIA; CELLS; HEMAGGLUTININ; LABORATORY animals; TISSUES

The article compares the H5N1 virus attachment to lower respiratory tract of humans and four animal species. Highly pathogenic avian influenza virus of the subtype H5N1 may cause infection of the lower respiratory tract (LRT) and severe pneumonia in humans. The cell types in the LRT to which the virus attaches are unknown for both humans and experimental animals. Although attachment is not the only factor required for virus replication, this information is important both to better understand the pathogenesis of H5N1 influenza and to assess the suitability of animal models. Influenza viruses attach to host cells by binding of the hemagglutinin to sialosaccharides on the host cell surface. For a more direct method, which was modified from a previously used technique, researchers incubated formalin-fixed, paraffin-embedded tissue sections with formalin-inactivated fluorescein isothiocyanate (FITC)-Tabeled H5N1 virus and detected virus with a peroxidase-labeled rabbit antibody to FITC that was amplified with a tyramide signal amplification system. Tissues comprised histologically normal LRT, as well as trachea from three individuals of each of the following species: human, mouse, ferret, cynomolgus macaque, and domestic cat.