Human effector/memory CD4 T cell subsets: deep TCR profiling.

Clonal fate of helper T cells is governed by early costimulatory signals but may also depend on the mode of TCR interaction with peptide-MHC on APCs. We investigate TCR repertoires of eight effector/memory CD4+ T-cell subsets (Th1, Th2, nonclassical Th2 (Th2a), Th17, Th1-17, Tfh, Treg, Th22), revealing subset-specific physicochemical and recombinational features reproducible across donors. At a threshold of 3 reads per UMI, the number of obtained UMI-labeled cDNA molecules per repertoire per sample ranged from 5,300 to 303,500, and the number of CDR3 clonotype variants at the nucleotide level per repertoire per sample ranged from 1,200 to 83,200. Deep unbiased TCR profiling allowed us to assess the natural level of in vivo CD4+ subsets plasticity. We observed a major clonal exchange between Th17/Th22/Th2/Th2a and the high stability of Treg and Tfh subsets. The latter two subsets also show higher repertoire publicity across donors. Tfh repertoire features reflect those of mature antibodies and indicate stringent selection of highly antigen-specific, low cross-reactive TCRs. We conclude that functional subsets are marked with non-random universal for donors and specific features of passed selection. In future TCR sequencing applications, subset-specific profiling could provide better insights of normal and pathological states of adaptive immunity compared to the classical approach when TCR profiling is performed on bulk T cells or after rough division into CD4 and CD8-enriched populations. Overall design: Dataset consists of 86 samples: T cell receptor clonesets from 5 healthy donors. For each of the donors, 8 functional CD4 T cell subsets were sorted and for each subset alpha and beta TCR libraries were prepared for NGS. Deep TCR profiling was achieved with UMI libraries barcoding according to Milaboratory protocol. Additionally, for 3 samples from donor 4 there are biological replicates: 3 replicate TCR alpha and 3 TCR beta libraries.