Affinity profiling of antibody responses against SARS-CoV-2

Summary

A critical part of the body’s immune response to a pathogen, such as a virus, is the production of antibodies that recognise specific parts of the invading pathogen (called antigens) and help the immune system to fight and eventually clear the infection.

Two fundamental properties of the antibody response are its magnitude (antibody concentration) and its strength (binding affinity to an antigen). We have recently developed a novel immunoassay that enables measurement of antibody concentration and affinity directly in patient serum and adapted it to quantify the antibody response against SARS-CoV-2 (the virus causing COVID-19).

With the help of NIHR BioResource, we examined sera from patients with different COVID-19 severity that were collected soon after infection and several months later. We found that patients developed antibodies that varied widely in their affinity to viral antigens and, importantly, that this response continued to mature after the infection was cleared (binding affinity became stronger). We are now examining sera from individuals that underwent vaccination against SARS-CoV-2 and aim to profile the generated antibody response against common variants of the virus.

We anticipate that this study will increase our understanding of the nature and individual variability of immune responses against this virus and provide important clues to help define the adequacy of immune protection after SARS-CoV-2 infection and after vaccination.

We would like to thank all the Volunteers from the BioResource who gave their time and participated in this research.