We have developed an mRNA-based high-throughput analysis technology and bioinformatics methods to analyze T-cell receptor repertoires within neonates and adults (Ravens et al., 2017). Initial data of defined patient cohorts indicates (i) a postnatal, extrathymic maturation of T cells (Ravens et al., 2017; DiLorenzo et al., 2019) and (ii) that viral infections leave a sustained footprint within the antigen receptor repertoire (Ravens et al., 2017; Ravens et al., 2018). The latter results propose that antigen receptor repertoires might serve as valuable biomarkers. More recently, we found that defined T cells develop in the early human thymus and immediately expand in response to the microbiota after preterm birth (Ravens, Fichtner et al., 2020, Tan, Fichtner et al., 2021).
Altogether, these findings reflect the developmental plasticity and suggest options for an iatrogenic imprinting of innate and adaptive immunity to promote immune maturation and adaptation during early life in individuals at high risk for infection- and immune-mediated diseases. Together with RG Viemann (RESIST project B1) we work on how defined factors influence the functional maturation of T cells and B cells within preterm infants and how the expressed antigen-receptor repertoire is shaped during early life.