Interferon action in animal cells.

In an attempt to clarify the mechanism(s) by which interferon acts, mutant mouse cells with possible alterations to the interferon system were studied. The cell cultures used in this work included interferon-sensitive and interferon-resistant L1210 cells, and two virus-resistant mutants of 3T6 cells, which were studied in conjunction with the parental cells. It had previously been indicated that glycolipids were involved in the interaction between cell and interferon. The glycolipids of the parental L1210S cells and of the interferon-resistant subline (L1210R) were thus analysed and compared. It was shown that L1210R cells lacked some of the glycolipids which were present in the parental cells; furthermore, L1210R cells could be shown to respond to interferon after pre-incubation of the cells with certain glycolipid mixtures. It had previously been proposed that a virus-resistant mutant of 3T6 cells, A2, was constitutive for the anti-viral state or for interferon production. A novel ribosome-associated protein had previously been shown to be present in interferon-treated cells, and extracts containing the protein had inhibited viral protein synthesis in vitro. A similar protein was shown to be present in two virus-resistant mutants and in the interferon-treated parental cells. This protein was not detected in untreated parental cells. The experiments presented indicate that an alteration to the interferon system is responsible for the characteristic virus-resistance of the mutants, and that an important component in the response of cells to interferon is a novel ribosome-associated protein. A model of interferon action which proposes a selective inhibition of viral translation was constructed. An extension of this model includes proposed mechanisms of interferon induction and action. The results of experiments which were designed to test the model are presented.