IL17A and uveitis: As shown earlier in an uveitis model, a response by IL-17-producing γδ T cells enhances the ensuing response of αβ Th17 cells stimulated by subcutaneous immunization [28], and although they are pathogenic in this model, Th17 cells have proven to be critical for host resistance to certain pathogens, particularly fungi and extracellular bacteria [reviewed in [29]].