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RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
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00:57Viral Recombination
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Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
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01:51Vaccinations
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00:36Viral Mutations
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A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material...
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02:28Leaky Scanning
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During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R...
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01:12Immunofluorescence Microscopy
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Related Experiment Video
Updated: Dec 30, 2025
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A Luciferase-fluorescent Reporter Influenza Virus for Live Imaging and Quantification of Viral Infection
Published on: August 14, 2019
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Summary
Developing an effective influenza vaccine is challenging due to surface antigen changes. While current vaccines are imperfect, improved purification lessens reactions, offering the best available control against influenza virus.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- Influenza virus surface antigens undergo frequent changes, complicating vaccine development.
- Antigenic drift results in minor changes, allowing some vaccine efficacy.
- Antigenic shift involves major changes, significantly reducing vaccine effectiveness.
Purpose of the Study:
- To summarize the challenges and advancements in influenza vaccine development.
- To highlight the impact of antigenic variation on vaccine efficacy.
- To discuss improvements in vaccine purification and their benefits.
Main Methods:
- Review of influenza virus antigenic properties and their impact on vaccine effectiveness.
- Analysis of the relationship between antigenic drift/shift and vaccine performance.
Main Results:
- Influenza vaccine effectiveness is significantly influenced by the extent of viral surface antigen changes.
- Improvements in vaccine purification have reduced adverse reactions.
- Current influenza vaccines, despite limitations, remain the primary control measure.
Conclusions:
- Continuous monitoring of influenza virus evolution is crucial for vaccine design.
- Enhanced purification processes have improved vaccine safety and tolerability.
- Despite ongoing challenges, influenza vaccines represent the most effective public health intervention available.