Quantifying Crosstalk Among Interferon-
, Interleukin-12, and Tumor Necrosis Factor Signaling Pathways Within a TH1 Cell Model
David J. Klinke II1,2,3*,
Ning Cheng1, and
Emily Chambers3
1 Department of Chemical Engineering, West Virginia University, Post Office Box 6102, Morgantown, WV 26506, USA.
2 Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA.
3 Department of Immunology, Microbiology, and Cell Biology, West Virginia University, Morgantown, WV 26506, USA.
Abstract:
T helper (TH) cells integrate biochemical cues present in the tissue microenvironment and produce cytokines that orchestrate immune responses. Previous discoveries have revealed a qualitative understanding of how TH cells process this biochemical information; however, the lack of methods to quantify how well these depictions apply to a particular cell type limits our ability to translate our knowledge of the immune response from one biological system to another. We used model-based inference methods and quantitative flow cytometric analysis in mouse TH1 cells to determine the relative contributions of different putative branches in the signaling network that responds to the cytokine interleukin-12 (IL-12), which links innate and adaptive immunity. The response of TH1 cells to IL-12 exhibited hysteresis because it depended on both current and past exposure and engaged a positive feedback mechanism through the direct activation of signal transducer and activator of transcription 1. The hysteresis in the dose-response curve to IL-12 created a transient "memory" by sustaining cytokine secretion after the withdrawal of the stimulus. In summary, this combined experimental and computational approach illustrates how model-based inference can be used to better understand how cells process and act upon biochemical cues present in the tissue microenvironment.
* To whom correspondence should be addressed. E-mail: david.klinke{at}mail.wvu.edu