Purification of Influenza Virions

Area of Science:

• Virology
• Biochemistry
• Immunology

Background:

• Influenza virions are critical for virological research.
• Efficient purification methods are essential for downstream applications.
• Existing methods may co-purify contaminants like microvesicles.

Purpose of the Study:

• To describe basic workflows for concentrating and purifying influenza virions.
• To present ultracentrifugation-based methods for influenza virion concentration.
• To offer optional steps for enhancing purification stringency and separating filamentous strains.

Main Methods:

• Ultracentrifugation for concentrating influenza virions from cell culture media or allantoic fluid.
• Optional steps involving viral receptor binding and cleaving activity enrichment.
• Density gradient protocol for separating filamentous influenza virions by morphology.
• Indirect immunofluorescence and automated image analysis for measuring filamentous virion length.

Main Results:

• Multiple ultracentrifugation approaches yield influenza virions with varying purity levels.
• Optional steps effectively increase purification stringency by reducing microvesicle co-purification.
• A density gradient protocol successfully separates filamentous influenza virions based on morphology.
• A method for measuring filamentous virion length is provided for morphology monitoring.

Conclusions:

• The described methods provide robust workflows for influenza virion concentration and purification.
• These protocols are adaptable for both spherical and filamentous influenza strains.
• Purified influenza virions are suitable for diverse downstream applications in virology, biochemistry, and immunology.