The T cell receptor repertoire reflects the early dynamics of the immune response to vaccination

Abstract

Early ascertainment of the immune response to vaccinations is important. The T cell receptor (TCR) is a promising target to achieve this, with the complete TCR repertoire in PBMCs reflecting the T cells present in an individual. To this end, we developed Tseek, an unbiased and accurate method for profiling the TCR repertoire by sequencing the TCR α and β chains and developing a suite of tools for repertoire analysis. We explored the T cell response to both the COVID-19 mRNA vaccine (n=9) and the seasonal inactivated Influenza vaccine (n=5) at several time points. Neutralizing antibody titers were also measured in the covid vaccine samples. The COVID-19 vaccine elicited a broad T cell response involving multiple expanded clones, whereas the Influenza vaccine elicited a narrower response involving fewer clones. Distinct T cell clones responded at different time points over a month, providing temporal details lacking in the antibody measurements. The physical symptoms following administration of the vaccinations were not indicative of the TCR/antibody responses while the TCR responses broadly presaged the antibody responses. Additionally, the TCR repertoire is akin to a fingerprint: donors of blood samples taken years apart could be identified from the TCR repertoire. TCR repertoire profiling shows great promise as an early and sensitive measure of the adaptive immune response to vaccination, which can help improve immunogen selection and optimize vaccine dosage and spacing between doses.