FACTORS INHIBITING IFN ACTIVITY

Several factors may inhibit the activity of IFNs. Some of these occur naturally, others are therapy-induced or artificial. Naturally occurri ng antibodies appear to have a much broader reactivity than therapy-in duced antibodies. Naturally induced antibodies are reported in patient s suffering from chronic graft-versus-host disease after bone marrow t ransplantation. Differences in the reported immunogenicity between int erferons may not be due to the minor variation in amino acid sequence. The clinical significance of therapy-induced antibodies has been uncl ear. In patients treated for chronic hepatitis C, antibody formation i s closely related to relapse. In animal studies the efficacy of treatm ents targeting the IFN receptor interaction has been shown. Soluble IF N-gamma receptor inhibits the development of autoimmune diseases in mi ce. Monoclonal antibodies to the IFN-alpha receptor protects against a llograft rejections in monkeys. Two naturally occurring inhibitors of IFN action were reported. The clinical significance and structure of t hese inhibitors remain elusive.