These research results were published online in the British Journal of Haematology.

Previously, B-cell receptor (BCR) repertoire analysis has provided gene sequence data of antibodies (B cell receptors), but it was difficult to use this data to evaluate the immunological reactions to specific antigens.

During the repertoire analysis, the team found that the immunological reactions could be evaluated by "sampling over time in the short time period wherein immunity is activated" and "utilizing the BCR gene sequence database for specific antigens."

This analysis is not the conventional analysis using protein level, such as "the measurement of antibody titers using the ELISA method," but an analysis using mRNA level. Therefore, evaluation is possible for samples with extremely elevated antibody titers after prophylactic administration of antibody preparations (proteins).

Detailed information can be derived, such as antibody epitopes expressed in immunological reactions or neutralization activity, if there is additional information in respect of the antibodies used. By utilizing this method to investigate immune responses following the administration of mRNA vaccines, it will be possible to evaluate the functionality of mRNA formulations.

In recent years, genetically-engineered antibody preparations, such as tixagevimab and cilgavimab, have been widely administered as preventative drugs, primarily for cases with compromised immune systems where there is insufficient antibody production after inoculation with mRNA SARS-CoV-2 vaccines.