Psoriasis is a chronic inflammatory skin disease characterized by Th17 responses. Recent evidence has identified Langerhans cells to have a key role in disease pathogenesis, with constitutive high expression of CD1a and capacity to present lipid antigens to T cells. Phospholipase A enzymes generate neolipid antigens for recognition by CD1a-reactive T cells; however, the broader enzymatic pathways of CD1a lipid ligand generation have not been thoroughly investigated. In this study, we used immunofluorescence of skin and ELISpot analyses of CD1a-reactive T cells to investigate the role of the lipase acyloxyacyl hydrolase (AOAH) in CD1a ligand generation with relevance to the pathogenesis of psoriasis. We found that the PLA activity of rAOAH leads to the activation of circulating CD1a auto-reactive T cells, leading to the production of IFN-γ and IL-22. Circulating AOAH-responsive CD1a-reactive T cells from patients with psoriasis showed elevated IL-22 production. We observed that AOAH is highly expressed in psoriatic lesions compared to healthy skin. Overall, these data present a role for AOAH in generating antigens that activate circulating lipid-specific CD1a-restricted T cells and, thus, contribute to psoriatic inflammation. These findings suggest that inhibition of PLA activity of AOAH may have therapeutic potential for individuals with psoriasis.
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http://dx.doi.org/10.1002/eji.202149485 | DOI Listing |
J Invest Dermatol
April 2024
Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address:
Human Langerhans cells highly express CD1a antigen-presenting molecules. To understand the functions of CD1a in human skin, we used CD1a tetramers to capture T cells and determine their effector functions and TCR patterns. Skin T cells from all donors showed CD1a tetramer staining, which in three cases exceeded 10% of skin T cells.
View Article and Find Full Text PDFEur J Immunol
October 2023
Division of Rheumatology, Inflammation and Immunity, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
In addition to serving as the main physical barrier with the outside world, human skin is abundantly infiltrated with resident αβ T cells that respond differently to self, infectious, microbiome, and noxious stimuli. To study skin T cells during infection and inflammation, experimental biologists track T-cell surface phenotypes and effector functions, which are often interpreted with the untested assumption that MHC proteins and peptide antigens drive measured responses. However, a broader perspective is that CD1 proteins also activate human T cells, and in skin, Langerhans cells (LCs) are abundant antigen presenting cells that express extremely high levels of CD1a.
View Article and Find Full Text PDFEur J Immunol
March 2022
Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
Psoriasis is a chronic inflammatory skin disease characterized by Th17 responses. Recent evidence has identified Langerhans cells to have a key role in disease pathogenesis, with constitutive high expression of CD1a and capacity to present lipid antigens to T cells. Phospholipase A enzymes generate neolipid antigens for recognition by CD1a-reactive T cells; however, the broader enzymatic pathways of CD1a lipid ligand generation have not been thoroughly investigated.
View Article and Find Full Text PDFMol Cells
May 2021
Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea.
Sci Immunol
December 2017
Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, National Institute for Health Research (NIHR) Biomedical Research Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
Group 2 innate lymphoid cells (ILC2) are effectors of barrier immunity, with roles in infection, wound healing, and allergy. A proportion of ILC2 express MHCII (major histocompatibility complex II) and are capable of presenting peptide antigens to T cells and amplifying the subsequent adaptive immune response. Recent studies have highlighted the importance of CD1a-reactive T cells in allergy and infection, activated by the presentation of endogenous neolipid antigens and bacterial components.
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