Browsing by Author "Fan, Lin"

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    CD4 T cells but not Th17 cells are Required for Mouse Lung Transplant Obliterative Bronchiolitis
    (Wiley, 2015-07) Wu, Qiang; Gupta, Pawan Kumar; Suzuki, Hidemi; Wagner, Sarah R.; Zhang, Chen; Cummings, Oscar W.; Fan, Lin; Kaplan, Mark H.; Wilkes, David S.; Shilling, Rebecca A.; Department of Pediatrics, Indiana University School of Medicine
    Lung transplant survival is limited by obliterative bronchiolitis (OB), but the mechanisms of OB development are unknown. Previous studies in a mouse model of orthotopic lung transplantation suggested a requirement for IL-17. We have used this orthotopic mouse model to investigate the source of IL-17A and the requirement for T cells producing IL-17A. The major sources of IL-17A were CD4+ T cells and γδ T cells. Depletion of CD4+ T cells led to a significantly decreased frequency and number of IL-17A+ lymphocytes and was sufficient to prevent acute rejection and OB. However, mice with STAT3-deficient T cells, which are unable to differentiate into Th17 cells, rejected lung allografts and developed OB similar to control mice. The frequency of IL-17A+ cells was not decreased in mice with STAT3-deficient T cells due mainly to the presence of IL-17A+ γδ T cells. Deficiency of γδ T cells also did not affect the development of airway fibrosis. Our data suggest that CD4+ T cells are required for OB development and expansion of IL-17A responses in the lung, while Th17 and γδ T cells are not absolutely required and may compensate for each other.
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    Role of Complement Activation in Obliterative Bronchiolitis Post Lung Transplantation
    (The American Association of Immunologists, Inc., 2013-10-15) Suzuki, Hidemi; Lasbury, Mark E.; Fan, Lin; Vittal, Ragini; Mickler, Elizabeth A.; Benson, Heather L.; Shilling, Rebecca; Wu, Qiang; Weber, Daniel J.; Wagner, Sarah R.; Lasaro, Melissa; Devore, Denise; Wang, Yi; Sandusky, George E.; Lipking, Kelsey; Pandya, Pankita; Reynolds, John; Love, Robert; Wozniak, Thomas; Gu, Hongmei; Brown, Krista M.; Wilkes, David S.; Department of Medicine, School of Medicine,
    Obliterative bronchiolitis (OB) post lung transplantation involves IL-17 regulated autoimmunity to type V collagen and alloimmunity, which could be enhanced by complement activation. However, the specific role of complement activation in lung allograft pathology, IL-17 production, and OB are unknown. The current study examines the role of complement activation in OB. Complement regulatory protein (CRP) (CD55, CD46, Crry/CD46) expression was down regulated in human and murine OB; and C3a, a marker of complement activation, was up regulated locally. IL-17 differentially suppressed Crry expression in airway epithelial cells in vitro. Neutralizing IL-17 recovered CRP expression in murine lung allografts and decreased local C3a production. Exogenous C3a enhanced IL-17 production from alloantigen or autoantigen (type V collagen) reactive lymphocytes. Systemically neutralizing C5 abrogated the development of OB, reduced acute rejection severity, lowered systemic and local levels of C3a and C5a, recovered CRP expression, and diminished systemic IL-17 and IL-6 levels. These data indicated that OB induction is in part complement dependent due to IL-17 mediated down regulation of CRPs on airway epithelium. C3a and IL-17 are part of a feed forward loop that may enhance CRP down regulation, suggesting that complement blockade could be a therapeutic strategy for OB.