Dendritic cells are specialized antigen-presenting cells that are unique in their capacity to efficiently sensitize naive T lymphocytes to antigen. DCs can also affect the quality of T cell responses. For instance, DCs that secrete high levels of IL-12 can functionally polarize CD4+ T cells into IFN-gamma-high IL-4/IL-5-low TH1 type effectors. IL-12 can also enhance the capacity of sensitized CD8+ T cells to directly recognize and kill tumor targets through a mechanism that includes dramatic enhancement of T cell functional avidity (i.e. antigen sensitivity). This finding places a new emphasis on IL-12 secretion by DCs as a strategy to improve anticancer vaccines. IL-12 secretion by mature DCs is conditional, however, requiring 2 signals to achieve maximized IL-12 production. The first signal is a priming signal and is supplied by IFN-gamma. The second is a maturation stimulus supplied by LPS or CD40 ligand. We have recently shown that in vitro transcribed ssRNA mimicking structures associated with bacterial RNA can substitute for IFN-gamma as a priming signal to maximize IL-12 secretion by human monocyte-derived DCs. This finding presents the unique opportunity to formulate 2nd generation RNA vaccines that not only deliver antigenic information to DCs but also modulate their function so as to maximize direct tumor recognition and killing properties of DC-sensitized T cells. It also offers the chance to characterize a completely novel discriminatory faculty of the innate immune system. This proposal therefore seeks to understand and exploit bacterial RNA structures that induce IL-12 secretion in DCs for the directed goal of improving anti-cancer vaccines.
The specific aims are 1) To define the structural parameters of ssRNA necessary to prime DC for IL-12 secretion and to incorporate them into a MART-1-encoding RNA-based vaccine; 2) To define the signal transduction pathways activated by ssRNA that regulate IL-12 secretion by DCs, and 3) To evaluate the adjuvant properties of ssRNA for modulating DC and T cell function. It is expected that these studies will shed light on a previously uncharacterized mode of discrimination by the innate immune system that will have practical applications in the formulation of RNA-based vaccines and vaccine adjuvants for cancer and infectious diseases.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA100163-04
Application #
7414116
Study Section
Cancer Immunopathology and Immunotherapy Study Section (CII)
Program Officer
Howcroft, Thomas K
Project Start
2005-06-27
Project End
2010-04-30
Budget Start
2008-05-01
Budget End
2010-04-30
Support Year
4
Fiscal Year
2008
Total Cost
$229,214
Indirect Cost
Name
Cleveland Clinic Lerner
Department
Surgery
Type
Schools of Medicine
DUNS #
135781701
City
Cleveland
State
OH
Country
United States
Zip Code
44195
Paustian, Christopher; Taylor, Patricia; Johnson, Terrence et al. (2013) Extracellular ATP and Toll-like receptor 2 agonists trigger in human monocytes an activation program that favors T helper 17. PLoS One 8:e54804
Paustian, Christopher; Caspell, Richard; Johnson, Terrence et al. (2011) Effect of multiple activation stimuli on the generation of Th1-polarizing dendritic cells. Hum Immunol 72:24-31
Taylor, Patricia R; Paustian, Christopher C; Koski, Gary K et al. (2010) Maturation of dendritic cell precursors into IL12-producing DCs by J-LEAPS immunogens. Cell Immunol 262:1-5
Zheng, Rongxiu; Cohen, Peter A; Paustian, Christopher A et al. (2008) Paired Toll-like receptor agonists enhance vaccine therapy through induction of interleukin-12. Cancer Res 68:4045-9
Koski, Gary K; Cohen, Peter A; Roses, Robert E et al. (2008) Reengineering dendritic cell-based anti-cancer vaccines. Immunol Rev 222:256-76
Czerniecki, Brian J; Koski, Gary K; Koldovsky, Ursula et al. (2007) Targeting HER-2/neu in early breast cancer development using dendritic cells with staged interleukin-12 burst secretion. Cancer Res 67:1842-52
Czerniecki, Brian J; Roses, Robert E; Koski, Gary K (2007) Development of vaccines for high-risk ductal carcinoma in situ of the breast. Cancer Res 67:6531-4