Gene expression of early memory and effector precursor CD8 T cells generated by differential TCR signaling strength

Asymmetric cell division (ACD) and the strength of initial T cell receptor (TCR) signaling are both implied to contribute to the establishment of cellular heterogeneity and CD8 T cell effector and memory differentiation. However, on a single cell level it remained unclear whether ACD generates progeny of different fates and whether the strength of TCR signaling affects this mechanism. Therefore, we developed experimental systems allowing monitoring the fate of single daughter cell progenies derived from an ACD either induced by weak or strong TCR stimulation by in vitro live imaging. We used the combinatorial expression of TCF1 and CD62L as markers indicating fate specification a few days after activation and analyzed the transcriptional profiles of in vitro generated CD62L+TCF1+ and CD62L-TCF1- cells derived from either antibody-induced (AB) activation or from gp33 (high affinity) or C6 (low affinity) peptide stimulation and compared them to in vivo generated effector and memory cells, respectively. Therefore, we sorted CD62L+TCF1+ and CD62L-TCF1- cells on day 6 post activation, followed by bulk RNA sequencing and found that CD62L+TCF1+ cells transcriptionally resembled in vivo generated memory cells, whereas CD62L-TCF1- cells were similar to in vivo generated effector cells.