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Gradual changes of influenza virions during passage of undiluted material
Abstract:
Defective influenza virions undergo gradual changes during passage of undiluted material: the amount of RNA in virions diminishes, the equimolarity of the RNA segments is lost and the interfering activity of defective virions decreases. Defective virions of early passages have a small deficiency in genetic material and at a high m.o.i. induce the synthesis of the complete set of virus-specific proteins. Defective virions from later passages are characterized by a considerable deficiency in genetic material and a decrease in the amount of high mol. wt. RNA segments. They do not demonstrate complementation and at a high m.o.i. do not induce the synthesis of virus-specific proteins, thus revealing analogous defects in the genome of the majority of defective virions. The characteristics of protein synthesis in cells infected with these virions are similar to those in uninfected cells. During undiluted passage of influenza virus the cyclic production of defective and infectious virions takes place.
Insights
During serial undiluted passages, defective influenza virions lose genetic material and RNA segments, diminishing their ability to induce viral protein synthesis. This leads to cyclic production of defective and infectious virions.
Area of Science:
- Virology
- Molecular Biology
Background:
- Defective influenza virions (DIs) are generated during virus replication.
- Understanding DI evolution during serial undiluted passages is crucial for viral dynamics.
Purpose of the Study:
- To investigate the alterations in defective influenza virions during serial undiluted passages.
- To characterize the impact of these changes on viral protein synthesis and infectivity.
Main Methods:
- Serial undiluted passages of influenza virus.
- Analysis of viral RNA content and segment equimolarity.
- Assessment of defective virion interfering activity.
- Evaluation of virus-specific protein synthesis induction at high multiplicity of infection (m.o.i.).
Main Results:
- Defective virions progressively lost RNA and equimolarity of segments during passages.
- Early passage DIs induced complete viral protein synthesis; later passage DIs showed reduced or no induction.
- Later passage DIs exhibited genome defects, lacked complementation, and showed protein synthesis similar to uninfected cells.
- Cyclic production of defective and infectious virions was observed.
Conclusions:
- Serial undiluted passages induce genomic defects in influenza virions, leading to loss of function.
- These defects impact viral protein synthesis and contribute to the cyclic nature of defective and infectious virion production.