title: Functionality of dengue virus specific memory T cell responses in individuals who were hospitalized or who had mild or subclinical dengue infection.
abstract: BACKGROUND
  Although antibody responses to dengue virus (DENV) in naturally infected individuals have been extensively studied, the functionality of DENV specific memory T cell responses in relation to clinical disease severity is incompletely understood.
  
  
  RESULTS
  Using ex vivo IFNγ ELISpot assays, and by determining cytokines produced in ELISpot supernatants, we investigated the functionality of DENV-specific memory T cell responses in a large cohort of individuals from Sri Lanka (n=338), who were naturally infected and were either hospitalized due to dengue or had mild or sub clinical dengue infection. We found that T cells of individuals with both past mild or sub clinical dengue infection and who were hospitalized produced multiple cytokines when stimulated with DENV-NS3 peptides. However, while DENV-NS3 specific T cells of those with mild/sub clinical dengue infection were more likely to produce only granzyme B (p=0.02), those who were hospitalized were more likely to produce both TNFα and IFNγ (p=0.03) or TNFα alone. We have also investigated the usefulness of a novel T cell based assay, which can be used to determine the past infecting DENV serotype. 92.4% of DENV seropositive individuals responded to at least one DENV serotype of this assay and none of the seronegatives responded. Individuals who were seronegative, but had received the Japanese encephalitis vaccine too made no responses, suggesting that the peptides used in this assay did not cross react with the Japanese encephalitis virus.
  
  
  CONCLUSIONS
  The types of cytokines produced by DENV-specific memory T cells appear to influence the outcome of clinical disease severity. The novel T cell based assay, is likely to be useful in determining the past infecting DENV serotype in immune-epidemiological studies and also in dengue vaccine trials.
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka; MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford NIHR Biomedical Research Centre and University of Oxford, Oxford, United Kingdom.
authors: Chandima
authors: C
authors: Jeewandara
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Thiruni N
authors: TN
authors: Adikari
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Laksiri
authors: L
authors: Gomes
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Samitha
authors: S
authors: Fernando
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: R H
authors: RH
authors: Fernando
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: M K T
authors: MK
authors: Perera
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Dinuka
authors: D
authors: Ariyaratne
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Achala
authors: A
authors: Kamaladasa
authors: MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford NIHR Biomedical Research Centre and University of Oxford, Oxford, United Kingdom.
authors: Maryam
authors: M
authors: Salimi
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka.
authors: Shamini
authors: S
authors: Prathapan
authors: MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford NIHR Biomedical Research Centre and University of Oxford, Oxford, United Kingdom; Department of Dermatology, Churchill Hospital, Oxford, United Kingdom.
authors: Graham S
authors: GS
authors: Ogg
authors: Centre for Dengue Research, Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayawardanapura, Nugegoda, Sri Lanka; MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford NIHR Biomedical Research Centre and University of Oxford, Oxford, United Kingdom.
authors: Gathsaurie Neelika
authors: GN
authors: Malavige
mesh_terms: D003429:Cross Reactions; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003715:Dengue / Q000276:immunology* / Q000473:pathology / Q000821:virology; D003716:Dengue Virus / Q000145:classification / Q000276:immunology*; D058501:Enzyme-Linked Immunospot Assay; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory / Q000502:physiology*; D010455:Peptides / Q000276:immunology; D020365:RNA Helicases / Q000276:immunology; D012697:Serine Endopeptidases / Q000276:immunology; D013188:Sri Lanka; D013601:T-Lymphocytes / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000276:immunology*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D016207:Cytokines; D010455:Peptides; D020365:RNA Helicases; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases