Invariant natural killer T (iNKT) cells are innate lymphocytes whose functions are regulated by CD1d- restricted self and foreign glycolipid antigens. Humans develop a homologous T cell subset and, hence, much of what is learnt in mice can be extended to people as well. Emerging evidence indicates that iNKT cell deficiency in mice delays bacterial clearance and immunity to them. Nonetheless, there is a major gap in our understanding of the precise role(s) iNKT cells play in conferring immunity to pathogens that cause human diseases in natural settings. To narrow this gap is highly significant because knowledge-based therapies, vaccine design and vaccination strategies against infectious diseases require an in-depth understanding of host responses to the inciting pathogen. Thus, the long-term goal of this project is to delineate the mechanism(s) by which iNKT cells regulate immunity to infectious diseases. Toward this goal, we have made significant new advances on the role of mouse iNKT cells in host response to Francisella tularensis (Ft). Ft subspp. tularensis, a Category A agent and potential bioweapon, causes lethal tularemia in people. Using a mouse model for this disease, we found that within a day, Ft subspp. novicida and the live vaccine strain (LVS) infection activated mouse splenic and hepatic iNKT cells to produce interferon-?, a key mediator of Ft clearance in both mice and humans. Further, iNKT cell deficiency increased splenic and hepatic Ft novicida load. Significantly, Ft inoculated wild type, but not iNKT cell deficient mice rapidly produced proinflammatory cytokines and chemokines, became morbid and died within a week. Guided by these exciting new preliminary data, we hypothesize that iNKT cell activation is critical for the control of Ft infection but the overzealous iNKT cell function leads to morbidity and mortality and fine-tuning these responses is essential for the control of microbial infections. To test this central hypothesis, we will: (1) elucidate the mechanism(s) by which iNKT cells regulate immunity to Ft and/or precipitate infection-induced disease;(2) determine the chemical nature of the Ft-derived antigen(s) that activates iNKT cells;and (3) develop ways to inhibit, deviate or deplete iNKT cells as a means to temper or prevent Ft infection-induced disease. New insights emerging from this study will significantly impact how we concoct iNKT cell-based therapies and vaccines and design vaccination strategies to pathogens that plague human kind.

Public Health Relevance

Francisella tularensis infections, which causes severe acute lethal tularemia, is considered a Category A pathogen and a serious bio-weapon because of the ease with which it can be grown in large quantities and made air-borne. The research proposed in this application will elucidate the mechanism(s) by which a subset of immune defense cells called natural killer T cells cause the pathogenesis of tularemia. The emerging new insight will then define ways to design novel vaccines to prevent the disease and to develop novel therapies to treat non-vaccinated individuals infected with Francisella tularensis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI042284-13
Application #
8431727
Study Section
Innate Immunity and Inflammation Study Section (III)
Program Officer
Miller, Lara R
Project Start
1998-08-01
Project End
2015-02-28
Budget Start
2013-03-01
Budget End
2015-02-28
Support Year
13
Fiscal Year
2013
Total Cost
$362,934
Indirect Cost
$130,284
Name
Vanderbilt University Medical Center
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
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Kumar, Amrendra; Suryadevara, Naveenchandra; Hill, Timothy M et al. (2017) Natural Killer T Cells: An Ecological Evolutionary Developmental Biology Perspective. Front Immunol 8:1858
Li, Bo; Siuta, Michael; Bright, Vanessa et al. (2016) Improved proliferation of antigen-specific cytolytic T lymphocytes using a multimodal nanovaccine. Int J Nanomedicine 11:6103-6121
Gilchuk, Pavlo; Hill, Timothy M; Guy, Clifford et al. (2016) A Distinct Lung-Interstitium-Resident Memory CD8(+) T Cell Subset Confers Enhanced Protection to Lower Respiratory Tract Infection. Cell Rep 16:1800-9
Hastings, Andrew K; Gilchuk, Pavlo; Joyce, Sebastian et al. (2016) Novel HLA-A2-restricted human metapneumovirus epitopes reduce viral titers in mice and are recognized by human T cells. Vaccine 34:2663-70
Joyce, Sebastian (2015) Immunoproteasomes edit tumors, which then escapes immune recognition. Eur J Immunol 45:3241-5
Erickson, John J; Lu, Pengcheng; Wen, Sherry et al. (2015) Acute Viral Respiratory Infection Rapidly Induces a CD8+ T Cell Exhaustion-like Phenotype. J Immunol 195:4319-30
Wen, Sherry C; Schuster, Jennifer E; Gilchuk, Pavlo et al. (2015) Lung CD8+ T Cell Impairment Occurs during Human Metapneumovirus Infection despite Virus-Like Particle Induction of Functional CD8+ T Cells. J Virol 89:8713-26
Gilchuk, Pavlo; Hill, Timothy M; Wilson, John T et al. (2015) Discovering protective CD8 T cell epitopes--no single immunologic property predicts it! Curr Opin Immunol 34:43-51
Hill, Timothy M; Gilchuk, Pavlo; Cicek, Basak B et al. (2015) Border Patrol Gone Awry: Lung NKT Cell Activation by Francisella tularensis Exacerbates Tularemia-Like Disease. PLoS Pathog 11:e1004975

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