Temperature-sensitive Mutants of Newcastle Disease Virus Affecting Interferon Induction

Abstract

SUMMARYTemperature-sensitive (ts) mutants of Newcastle disease virus (NDV) were isolated and studied for interferon (IFN) induction in primary chick embryo (CE) cells. At the non-permissive temperature (41 °C), there was no viral RNA synthesis or IFN induction by u.v.-treated virions except for ts-3 (RNA+), which did synthesize RNA at 41 °C, and whose u.v.-treated virions did induce IFN at this temperature. Another mutant (ts-4) induced IFN without irradiation, at the permissive temperature (37 °C). The minimum u.v. target size for IFN inducibility was unaffected by the mutation and corresponded to about 5 ~ of the genome required for the expression of infectivity. These results support the hypothesis that the appearance of NDV RNA immediately after infection (primary transcription) plays a key role in IFN induction.

In vivo interference by Newcastle disease virus in chickens, the natural host of the virus

“…NDV is a good interferon inducer and interferon is induced rapidly after infection [3,29,34]. Interferon inhibits virus attachment, penetration and replication and is a integral part of the host resistance against virus infections [25,28,36,46].…”

Purification and Characterization of Chick Interferon Induced by Viruses

“…30) as described previously (Kohase & Kohno, 1983). The medium (Eagle's MEM without CS) was collected at 24 h after induction and served as the starting IFN material.…”

A temperature-sensitive mutant of Newcastle disease virus defective in intracellular processing of fusion protein

“…Viral protein synthesis in infected cells. CE cells and purified stock viruses were prepared as described previously (5)(6)(7). Virus-specific protein synthesis was studied with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of infected cells labeled with [3H]methionine and chased for various times.…”