Human IL-17F is synthesized as a 153 aa precursor with a 20 aa signal sequence and a 133 aa mature region. Like IL-17A, IL-17F contains one potential site for N-linked glycosylation. IL-17A and IL-17F share 50% aa sequence identity. IL17-F homodimer is produced by an activated subset of CD4+ T cells, termed Th17. IL17-F has been shown to stimulate proliferation and activation of T-cells and PBMCs. IL-17F also regulates cartilage matrix turnover and inhibits angiogenesis.