Splenocytes were harvested from mice and Th1 and Tfh SMARTA cells FACS-sorted directly into RLT buffer. RNA was isolated using a single-cell RNA purification kit. SMART-Seq v4 Ultra Low Input RNA Kit for Sequencing was used per manufacturer's instructions for amplification of RNA and subsequent cDNA synthesis. All samples proceeded through NexteraXT DNA Library Preparation (Illumina) using NexteraXT Index Kit V1 or V2 Set A following manufacturer's instructions.