in order to dissociate the effect of virus and endogenous interferon on the induction process , we examined the gene expression in vero cells , which have undergone homozygous deletion of type 1 interferon genes , and in vnpt-159 cells , which were derived from vero cells by insertion of an inducible human interferon beta 1 gene .
C0021747
interferon
C0021743
type 1 interferon