1. TH17 and TH22 cells: A confusion of antimicrobial response with tissue inflammation versus protection 
Mübeccel Akdis, MD, PhD, Oscar Palomares, PhD, Willem van de Veen, MSc, Marloes van Splunter, Dipl Biol, Cezmi A. Akdis, MD 
Journal of Allergy and Clinical Immunology 
Volume 129, Issue 6, Pages (June 2012)
DOI: /j.jaci
Copyright © 2012 American Academy of Allergy, Asthma & Immunology Terms and Conditions

2. Fig 1
Differentiation pathways of CD4+ TH cell subsets. Depending on the adjuvant effects of the substances coexposed with the antigen and on the status of the cells and cytokines in the microenvironment, naive CD4+ T cells can differentiate into TH1, TH2, TH9, TH17, TH22, or follicular helper T cells (TFH). These T-cell subsets can promote different types of inflammatory responses based on their respective cytokine profiles, responses to chemokines, and interactions with other cells.
Journal of Allergy and Clinical Immunology  , DOI: ( /j.jaci )
Copyright © 2012 American Academy of Allergy, Asthma & Immunology Terms and Conditions

3. Fig 2
TH17 cell plasticity. In the presence of TGF-β and IL-6, naive CD4+ T cells differentiate into more regulated classical TH17 cells characterized by the production of more IL-21, IL-9, and IL-10. In contrast, without TGF-β but in the presence of IL-6, IL-1β, and IL-23, more pathogenic alternative TH17 cells producing high levels of IL-22, GM-CSF, and IFN-γ are generated. Both subsets produce IL-17A and IL-17F.
Journal of Allergy and Clinical Immunology  , DOI: ( /j.jaci )
Copyright © 2012 American Academy of Allergy, Asthma & Immunology Terms and Conditions

4. Fig 3
Role of TH17 and TH22 cells in inflammation and immunity. On infection with extracellular pathogens, DCs will be primed to secrete IL-6, TGF-β, IL-1β, and IL-23 when presenting microbial antigens to naive T cells. This drives TH17 differentiation. On activation, TH17 cells produce a range of proinflammatory cytokines and chemokines that act on fibroblasts, endothelial cells, mucosal epithelial cells, and skin keratinocytes, as well as macrophages, to secrete antimicrobial peptides, such as defensins and psoriasin, leading to clearance of the pathogens in a neutrophil-independent manner. On the other hand, the same cells produce IL-6 and IL-8, leading to the recruitment of neutrophils to the site of inflammation.
Journal of Allergy and Clinical Immunology  , DOI: ( /j.jaci )
Copyright © 2012 American Academy of Allergy, Asthma & Immunology Terms and Conditions