Antibody quantity versus quality after influenza vaccination

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Correlates of protection against influenza infection are not fully understood.
• Distinguishing between neutralizing and non-neutralizing antibodies is crucial for assessing immune response.

Purpose of the Study:

• To characterize immune responses to influenza vaccination by differentiating antibody types.
• To evaluate potential correlates of protection against influenza.

Main Methods:

• Applied an ELISA strategy to distinguish antibodies against native viral surface antigens from those against internal/denatured proteins.
• Studied three vaccinated groups: repeated annual vaccination, elderly subjects, and Systemic Lupus Erythematosus patients versus controls.
• Measured antibody levels, antibody avidity against native virus, and hemagglutination-inhibition titers.

Main Results:

• Antibody increase post-vaccination was inversely related to pre-existing antibody levels.
• Most subjects showed minimal antibody increase but increased antibody avidity after vaccination.
• Antibodies against denatured proteins varied with vaccine formulation, with newer vaccines having less total protein.

Conclusions:

• A proposed index combining native antibody level, native antibody avidity, and hemagglutination-inhibition titer may serve as a useful measure of influenza immunity.
• Understanding antibody characteristics beyond simple titers is essential for evaluating vaccine effectiveness.