The T<sub>H</sub>17 cells form when T<sub>H</sub>0 cells are challenged with IL-6 and TGF-β to produce a number of cytokines that enhance the innate immune response <ref>{{citation|initiallast = Metcalfe|initialfirst = T|2last = Korn|2first = D|finallast = Kuchroo|finalfirst = V.K.|year = 2009|jtitle = IL-17 and Th17 Cells | The T<sub>H</sub>17 cells form when T<sub>H</sub>0 cells are challenged with IL-6 and TGF-β to produce a number of cytokines that enhance the innate immune response <ref>{{citation|initiallast = Metcalfe|initialfirst = T|2last = Korn|2first = D|finallast = Kuchroo|finalfirst = V.K.|year = 2009|jtitle = IL-17 and Th17 Cells |