s of the IL-17 family，IL-17A and IL17F. Proteins of the 6 homodimeric IL17 family show a cysteine knot motif that contains two disulfide-bonds. Human IL17A is produced as a 155 a.a precursor that includes a 23 amino acids signal sequence and a 132 amino acid chain that includes an N-linked glycosylation site. Human IL17F is produced as a 153 amino acid precursor with a 20 amino acid signal sequence and a 133 amino acid region. Similar to IL17A，IL17F also has an N-linked glycosylation site. Both proteins （IL17A & IL17F） share 50% amino acid sequence identity. Human IL17A & IL17F show approximately 60% homology in their amino acid sequence to mouse IL-17A and IL-17F. Interleukin-17A/F and IL17A，IL17F homodimers are manufactured by activted CD4+ T cells，called Th17. IL-23 causes Th17 lymphocytes to manufacture IL-17A/F. IL17RA and IL17RC form a heterodimer for the binding of IL17A and IL17F. IL-17A/F binds IL-17RA. Interleukin-17A/F induces chemokine production and airway neutrophilia with intermediate potency between IL17A （most potent） and IL17F （least potent）.
