title: IL-12 secretion by Langerhans cells stimulated with Candida skin test reagent is mediated by dectin-1 in some healthy individuals.
abstract: OBJECTIVE
  Our group and others have shown that serial intra-lesional injections of common warts with skin testing reagents such as Candida, mumps and Trichophyton are effective in regressing injected and non-injected warts. Anti-HPV T-cell responses appear to be induced. The goal of this study was to understand the mechanisms of how Candida skin testing reagent enhances immune responses.
  
  
  METHODS
  The following immunological features were studied to understand how Candida induces immune responses in healthy subjects: (1) proliferative capacity of T-cells upon exposure to Candida through monocyte-derived human Langerhans cells (LCs) measured using alamarBlue, (2) cytokine (IL-1β, IL-6, IL-8, IL-10, IL-12p40, IL-23Ap19, IFN-γ, and TNF- expression upon Candida stimulation of LCs by quantitative reverse transcription (qRT)-PCR and cytokine secretion by ELISA, (3) expression of pattern recognition receptors (PRRs) known to associate with Candida albicans (DC-SIGN, dectin-1, dectin-2, galectin-3, mincle, mannose receptor, Toll-like receptors 1, 2, 4, 6, and 9) on LCs by qRT-PCR, (4) role of dectin-1 in IL-12 production by antibody blocking, and (5) induction of Th1, Th2, and/or Th17 responses by intracellular cytokine staining of CD4 cells exposed to Candida pulsed LCs for IFN-γ, IL-4, and IL-17A.
  
  
  RESULTS
  T-cell proliferation upon stimulation with Candida-pulsed LCs was significantly higher compared to proliferation in the absence of Candida (p=0.004). The most frequently expressed cytokine in stimulated LCs was IL-12p40 mRNA, and IL-12p40 and IL-12p70 were also detected at protein levels. All other cytokine mRNAs examined were detected in the following order of decreasing frequency: IL23Ap19, IFN-γ, IL-1β, IL-6, IL-8, and IL-10. LCs expressed all PRRs examined. Anti-dectin-1 inhibited IL-12p40 mRNA production upon Candida stimulation of LCs from some healthy subjects. IFN-γ secretion was increased and IL-4 secretion was decreased in CD4 cells of a few healthy subjects, but IL-17A was essentially unchanged upon Candida treatment.
  
  
  CONCLUSIONS
  Proliferation of T-cells in a substantial majority of healthy subjects can be demonstrated with Candida stimulation. We show Th1 promotion and dectin-1 stimulation of LCs as potential mechanisms in some healthy subjects.
authors.affiliation: Department of Pathology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA. Electronic address: mnakagawa@uams.edu.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Nakagawa
authors.affiliation: Department of Pathology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Hannah N
authors.initials: HN
authors.lastname: Coleman
authors.affiliation: Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang 110001, China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Pathology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Jaclyn
authors.initials: J
authors.lastname: Daniels
authors.affiliation: Department of Pediatrics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: James
authors.initials: J
authors.lastname: Sikes
authors.affiliation: Department of Pediatrics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Microbiology and Immunology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Uma M
authors.initials: UM
authors.lastname: Nagarajan
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D018949:Antigens, CD1 / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002175:Candida / Q000737:chemistry* / Q000276:immunology; D049109:Cell Proliferation / Q000187:drug effects; D006262:Health; D064368:Healthy Volunteers; D006801:Humans; D007202:Indicators and Reagents / Q000494:pharmacology; D018664:Interleukin-12 / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007801:Langerhans Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D037181:Lectins, C-Type / Q000276:immunology / Q000378:metabolism*; D037241:Mannose-Binding Lectins / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012882:Skin Tests; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects; D000099181:Dectin-1
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D015820:Cadherins; D007202:Indicators and Reagents; D018664:Interleukin-12; D037181:Lectins, C-Type; D037241:Mannose-Binding Lectins; D051192:Receptors, Pattern Recognition; D000099181:Dectin-1; C419393:CD1a antigen; C121916:CD207 protein, human
keywords: Candida; Dectin-1; Interleukin-12; T-cell; Th1