Avian cells expressing the Newcastle disease virus hemagglutinin-neuraminidase protein are resistant to Newcastle disease virus infection.

The cDNA derived from the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) gene was inserted into a replication-competent Schmidt-Ruppin Rous sarcoma virus-derived vector. Chick embryo cells transfected with this vector expressed HN-sized protein which could be precipitated with anti-HN antibody. These cells adsorbed avian red blood cells and the cell surfaces exhibited neuraminidase activity while cells transfected with an antisense version of the gene were negative for hemadsorption and neuraminidase. The cells transfected with the retroviral vector containing the HN gene were resistant to infection by NDV and influenza virus, viruses which bind to sialic acid containing receptors, but sensitive to vesicular stomatitis virus (VSV). Cells transfected with the antisense version of the HN gene were sensitive to NDV, influenza virus, and VSV infection. Thus the HN protein-expressing cells are likely resistant to NDV and influenza virus due to the destruction of the cellular receptors by the neuraminidase of the HN protein. The expression of the influenza virus HA protein using the same retrovirus vector has been reported previously (L. A. Hunt, D. W. Brown, H. L. Robinson, C. W. Naeve, and R. G. Webster, 1988, J. Virol. 62, 3014-3019). Cells infected with this vector were sensitive to infection with influenza virus, NDV, and VSV. Thus expression of a viral surface protein does not necessarily confer resistance of the cell to the homologous virus.