library_construction_protocol: Capture and processing of single CD4+ T cells was performed using the Fluidigm C1 autoprep system. Sorted CD4+ T cells (50 cells/µl) were mixed with (ratio 6/4) C1 Cell Suspension Reagent (Fluidigm) and subsequently loaded onto a 5-10-μm-diameter C1 Integrated Fluidic Circuit (IFC; Fluidigm). Reverse transcription and cDNA preamplification were performed using the SMARTer Ultra Low RNA kit (Clontech). Sequencing libraries were prepared using Nextera XT DNA Sample Preparation kit with 96 indices (Illumina), according to the protocol supplied by Fluidigm. Size distribution in final libraries was analyzed by Bioanalyzer High Sensitivity DNA assay (Agilent) and library concentrations were quantified by Qubit High Sensitivity DNA assay (ThermoFisher).