IL-17A has emerged as a pivotal driver of tissue pathology in many immune-mediated inflammatory diseases. Despite sharing 50% sequence homology and the same signalling pathway, the role of IL-17F remains less clear. RNA sequencing of human IL-17 popualtions isolated using a cytokine capture technique identified clear transcriptional differences in IL-17A and IL-17F producing cells, with IL-17A producing cells showing enrichment for cytokine signaling and IL-17F producing cells showing enrichment for cellular replication. Overall design: Memory CD4+ T cells were isolated from PBMCs and activated with anti-CD3/CD28, IL-1b and IL-23 for 72 hours from n=6 individual donors. IL-17 secreting cells were captured using bispecific antibodies: CD45/IL-17A or CD45/IL-17F. Live cells were then washed and stained with fluorochrome conjugated antibodies towards IL-17A or IL-17F and FACS sorted.