@article {Salerno375840, author = {Fiamma Salerno and Julian J. Freen-van Heeren and Aurelie Guislain and Benoit P. Nicolet and Monika C. Wolkers}, title = {Costimulation through TLR2 drives polyfunctional CD8+ T cell responses}, elocation-id = {375840}, year = {2018}, doi = {10.1101/375840}, publisher = {Cold Spring Harbor Laboratory}, abstract = {Optimal T cell activation requires antigen recognition through the T cell receptor (TCR), engagement of costimulatory molecules, and cytokines. T cells can also directly recognize danger signals through the expression of toll-like receptors (TLRs). Whether TLR ligands have the capacity to provide costimulatory signals and enhance antigen-driven T cell activation is not well understood. Here, we show that TLR2 and TLR7 ligands potently lower the antigen threshold for cytokine production in T cells. To investigate how TLR triggering supports cytokine production, we adapted the protocol for flow cytometry-based fluorescence in situ hybridization (Flow-FISH) to mouse T cells. The simultaneous detection of cytokine mRNA and protein with single-cell resolution revealed that TLR triggering primarily drives de novo mRNA transcription. Ifng mRNA stabilization only occurs when the TCR is engaged. TLR2, but not TLR7-mediated costimulation, can enhance mRNA stability at low antigen levels. Importantly, TLR2 costimulation increases the percentage of polyfunctional T cells, a hallmark of potent T cell responses. In conclusion, TLR-mediated costimulation effectively potentiates T cell effector function to suboptimal antigen levels.}, URL = {https://www.biorxiv.org/content/early/2018/11/05/375840}, eprint = {https://www.biorxiv.org/content/early/2018/11/05/375840.full.pdf}, journal = {bioRxiv} }