Antibody affinity maturation is a critical step in development of functional antiviral immunity. However, accurate measurement of affinity maturation of polyclonal serum antibody responses to particulate antigens such as virions is challenging. 

The purpose of a new study published in The Journal of Infectious Diseases was to describe a novel avidity assay—employing bio-layer interferometry and dengue virus-like particles. After validation using anti-dengue monoclonal antibodies, the assay was used to assess avidity of antibody responses to a tetravalent dengue vaccine candidate (TAK-003) in children, adolescents and adults during two Phase 2 clinical trials, conducted in dengue endemic regions.

It was observed that vaccination increased avidity index and avidity remained high through one-year post vaccination. Neutralizing antibody titers and avidity index did not correlate. Yet, an association was found between neutralizing antibody titer and avidity index – in subjects with the highest degree of antibody affinity maturation. 

Hence, it was concluded that vaccination with TAK-003 stimulates polyclonal affinity maturation and functional antibody responses including neutralizing antibodies.

Source: The Journal of Infectious Diseases. 2021 Feb 3; jiab064. doi: 10.1093/infdis/jiab064.