title: Increased cytotoxicity of CD4+ invariant NKT cells against CD4+CD25hiCD127lo/- regulatory T cells in allergic asthma.
abstract: CD4+CD25(hi)CD127(lo/-) regulatory T cells (Treg) have been implicated in the resolution of asthma-associated inflammation while the opposite role of CD4+ invariant NKT (iNKT) cells has been the subject of recent investigations. Studies here focused on mechanisms of interaction between CD4+ iNKT cells and Treg to further explore their roles in allergic asthma (AA). Flow cytometry analysis revealed a significant increase in the expression of the natural cytotoxicity receptors NKp30 and NKp46 by CD4+ iNKT cells in AA subjects compared to healthy controls (HC) and non-allergic asthmatics (NA). Subsequent intracellular staining showed that CD4+ iNKT cells also expressed higher levels of granzyme B and perforin in AA than HC. In in vitro killing assays, AA CD4+ iNKT cells selectively killed autologous Treg, but not CD4+CD25- T cells, more potently than HC and NA counterparts. This increased cytotoxicity positively correlated with asthma severity and granzyme B/perforin expression of CD4+ iNKT cells. Furthermore, it could be abrogated by either inhibition of the granzyme B-/perforin-dependent cell death pathway or oral corticosteroid administration. Altogether, these findings suggest that increased cytotoxicity of CD4+ iNKT cells against Treg might contribute to dysfunctional cellular interactions in AA.
authors.affiliation: Department of Pediatrics, Pulmonary Center of Excellence, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Khoa D
authors.initials: KD
authors.lastname: Nguyen
authors.forename: Chris
authors.initials: C
authors.lastname: Vanichsarn
authors.forename: Kari C
authors.initials: KC
authors.lastname: Nadeau
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D053804:Granzymes / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D055627:Natural Cytotoxicity Triggering Receptor 1; D055628:Natural Cytotoxicity Triggering Receptor 3; D054353:Perforin / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents; C112260:NCR1 protein, human; C431710:NCR3 protein, human; D055627:Natural Cytotoxicity Triggering Receptor 1; D055628:Natural Cytotoxicity Triggering Receptor 3; D011971:Receptors, Immunologic; D054353:Perforin; D053804:Granzymes