A solid-phase enzyme-linked assay for influenza virus receptor-binding activity.

Area of Science:

• Virology
• Biochemistry
• Immunology

Background:

• Influenza virus receptor binding is typically assessed using haemagglutination (HA) and HA inhibition (HAI) tests.
• These traditional methods have limitations in sensitivity and quantitative analysis of virus-receptor interactions.

Purpose of the Study:

• To develop a novel, sensitive, and quantitative solid-phase enzyme-linked assay for characterizing influenza virus receptor-binding properties.
• To overcome the drawbacks associated with conventional HA and HAI assays.

Main Methods:

• A sandwich ELISA-like assay was developed using fetuin-coated microtitre plates to capture influenza viruses.
• Horseradish peroxidase (HRP)-labeled sialylglycoproteins (SGPs) were used to detect bound virus, with unlabeled compounds measured via competitive inhibition.
• The assay allows for the determination of affinity constants (Kd) and investigation of environmental factors affecting binding.

Main Results:

• The developed assay is sensitive, capable of detecting weak binding interactions, such as free N-acetylneuraminic acid (Kd ~10(-1)-10(-2) M⁻¹).
• The assay provides quantitative data, enabling the calculation of affinity constants.
• The system's components exhibit higher stability than red blood cells, facilitating studies on pH, ionic strength, and other factors.

Conclusions:

• The novel enzyme-linked assay offers a robust and sensitive alternative to traditional methods for studying influenza virus receptor interactions.
• This assay facilitates a more detailed understanding of the molecular basis of influenza virus tropism and host-pathogen interactions.
• The assay's quantitative nature and stability make it valuable for investigating factors influencing virus-receptor binding dynamics.