Localization fo the gene AVG for the antiviral expression of immune and classical interferon to the distal portion of the long arm of chromosome 21.

The responses of normal fibroblasts and of fibroblasts trisomic and monosomic for chromosome 21 to exogenously administered virus-induced (classical) and phytohemagglutinin-induced (immune) human interferon were determined. The virus-induced interferon was obtained from leukocytes treated with Sendai virus and from neonatal foreskin fibroblasts treated with Newcastle disease virus. With both classical and immune interferons, the mean response of the trisomic cell lines was three times that of the normal cells, whereas that of the monosomic lines was half or less that of the normal cells, Furthermore, a line trisomic for only the distal half of the long arm of chromosome 21 (q21 leads to qter) also demonstrated increased sensitivity to virus- and phytohemagglutinin-induced interferons, a fact that indicated that the gene responsible for the antiviral effect of interferon, AVG, is located on this part of chromosome 21. Responses to the two categories of interferon (virus-induced and phytohemagglutinin-induced) of individual cell lines of different degrees of sensitivity were strongly correlated (r=0.79). It is concluded, therefore, that despite their physical and antigenic differences, the antiviral expressions of both classical and immune interferons are ultimately mediated by the same genetic locus, AVG.