Interferon induction by viruses. XXII. Vesicular stomatitis virus-Indiana: M-protein and leader RNA do not regulate interferon induction in chicken embryo cells.

Several field isolates, strains, mutants, and revertants of vesicular stomatitis virus (VSV), Indiana (IN) serotype, were studied that differed greatly in their capacity to induce interferon (IFN) in aged chick embryo cells. The predicted M-protein amino acid sequence of a wild-type field isolate that induced > or = 10,000 units/ml IFN in chicken embryo cells was identical to that of a wild-type field isolate that induced < 2 units/ml and of a noninducing wild-type laboratory strain. The 47-base plus-strand leader RNA sequences were the same for five IFN-inducing, and eight noninducing independent isolates of wild-type VSV IN. Our data show that the M-protein and plus-strand leader RNA do not of themselves regulate the induction of IFN in this system. Because the capacity of VSV IN to induce IFN resides in virion-associated elements (Marcus and Sekellick, 1987, J. Interferon Res. 7, 269-284), the differences in IFN yield observed with various isolates must result from changes in other virion components that remain to be determined.