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CD8+ T Cell and NK Responses to a Novel Dengue Epitope: A Possible Role for KIR3DL1 in Dengue Pathogenesis: A Dissertation
Authors
Townsley, ElizabethFaculty Advisor
Anuja Mathew, PhDAcademic Program
MD/PhDUMass Chan Affiliations
MedicineDocument Type
Doctoral DissertationPublication Date
2014-04-03Keywords
Dissertations, UMMSCD8-Positive T-Lymphocytes
Dengue
Dengue Virus
Epitopes, T-Lymphocyte
HLA-B Antigens
Killer Cells, Natural
Peptides
Receptors, KIR3DL1
CD8-Positive T-Lymphocytes
Dengue
Dengue Virus
T-Lymphocyte Epitopes
HLA-B Antigens
Natural Killer Cells
Peptides
KIR3DL1 Receptors
Immunology of Infectious Disease
Immunopathology
Pathogenic Microbiology
Metadata
Show full item recordAbstract
Variation in the sequence of T cell epitopes between dengue virus (DENV) serotypes is believed to alter memory T cell responses during second heterologous infections contributing to pathology following DENV infection. We identified a highly conserved, novel, HLA-B57-restricted epitope on the DENV NS1 protein, NS126-34. We predicted higher frequencies of NS126-34-specific CD8+ T cells in PBMC from individuals undergoing secondary, rather than primary, DENV infection due to the expansion of memory CD8+T cells. We generated a tetramer against this epitope (B57-NS126-34TET) and used it to assess the frequencies and phenotype of antigen-specific T cells in samples from a clinical cohort of children with acute DENV infection established in Bangkok, Thailand. High tetramer-positive T cell frequencies during acute infection were seen in only 1 of 9 subjects with secondary infection. B57-NS126-34-specific, other DENV epitope-specific CD8+ T cells, as well as total CD8+ T cells, expressed an activated phenotype (CD69+ and/or CD38+) during acute infection. In contrast, expression of CD71 was largely limited to DENV-specific CD8+ T cells. In vitro stimulation of CD8+ T cell lines, generated against three different DENV epitopes, indicated that CD71 expression was differentially sensitive to stimulation by homologous and heterologous variant peptides with substantial upregulation of CD71 detected to peptides which also elicited strong functional responses. CD71 may therefore represent a useful marker of antigenspecific T cell activation. During the course of our analysis we found substantial binding of B57-NS126-34 TET to CD8- cells. We demonstrated that the B57-NS126-34 TET bound KIR3DL1, an inhibitory receptor on natural killer (NK) cells. NK sensitive target cells presenting the NS126-34 peptide in the context of HLA-B57 were able to dampen functional responses of only KIR3DL1+ NK cells. Analysis of the activation of an NK enriched population in our Thai cohort revealed peak activation during the critical time phase in patients with severe dengue illness, dengue hemorrhagic fever, compared to people with mild illness. Our data identified CD71 as biologically useful marker to study DENV-specific CD8+ T cell responses and highlighted the role of viral peptides in modulating NK cell activation through KIR-MHC class I interactions during DENV infection.DOI
10.13028/M27G7SPermanent Link to this Item
http://hdl.handle.net/20.500.14038/32067Rights
Copyright is held by the author, with all rights reserved.ae974a485f413a2113503eed53cd6c53
10.13028/M27G7S
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