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Multi-scale Modeling Consortium grant sponsored by the National Library of Medicine of
the National Institutes of Health


A multi-scale approach for understanding antigen presentation in immunity

Denise Kirschner, PI
Associate Professor
Departments of:
Microbiology and Immunology,
BioMedical Engineering,
and Program in Bioinformatics Faculty
Phone: (734) 647-7722
Fax: (734) 764-7723
E-mail: kirschne@umich.edu


Co-PIs and Collaborators:

Dr. Jennifer Linderman, Co-PI, Dept of Chemical Engineering, University of Michigan
Dr. JoAnne Flynn, Co-PI, Dept of Molecular Biology and Genetics, University of Pittsburgh
Dr. Mark Miller, Consultant, Dept of Pathology and Immunology, Washington University
Dr. Debashis Ghosh, Co-PI, Department of Biostatistics, University of Michigan

Students and postdoctoral Fellows on this project:

Dr. Tom Riggs, MD, PhD, Dept of Microbiology and Immunology, University of Michigan
Nicolas Perry, Dept of Biophysics, University of Michigan
Stewart Chang Program in Bioinformatics, University of Michigan

Technical support:

Joseph Waliga, Dept of Microbiology and Immunology, University of Michigan

Project Summary:

The human immune response works to either clear or control pathogens upon infection. Antigen presentation s critical to the immune response and is the process by which peptide fragments of pathogens are taken up by cells and displayed on the cell surface. Events at multiple scales (genetic molecular, cellular, tissue, and organ) are involved in antigen presentation. Briefly, antigen-presenting cells (ARC) take up pathogens at the site of infection. Once they have been taken up, they are then processed into peptides within the APC. These peptides then bind proteins known as the major histocompatibility complex (MHC). These peptide- MHC complexes (pMHC) are then displayed on the surface of the APC for recognition by T cells. In addition, the dynamics of antigen presentation and recognition are influenced by the larger tissue-level context in which they occur, namely the structured environment of the lymph node and ultimately by external compartmental dynamics of blood and the lymphatic system. A comprehensive understanding of the process of antigen presentation during an immune response will require an integrated picture of events that are occurring over multiple spatial and time scales. Mathematical models are tools that allow for such a multiscale investigation. Not surprisingly, since pathogens meet APCs continually as a first line of defense, many have evolved ways to inhibit antigen presentation. One such intracellular bacterial pathogen is Mycobacterium tuberculosis. Upon entering the lungs, M. tuberculosis is taken up by resident macrophages and then replicates. To evade immune surveillance, M. tuberculosis is known to inhibit antigen presentation of its host macrophage. The mechanisms by which M. tuberculosis achieves this inhibition have not been completely elucidated. Our specific aims include: building mathematical and statistical models to: predict affinity of peptides for different MHCII molecules with particular emphasis on the role that peptide length plays in determining affinity; describe the processing and the presentation events occurring in a single APC; describe antigen recognition and some of the downstream events by capturing interactions of cells within a single lymph node; capture relevant immune dynamics in the body in two-compartments of blood/lymph node. Integrating the models over multiple scales will be a key goal as well as utilizing data from non-human primate and mouse systems. Our specific goal is to use the models developed above towards understanding antigen presentation during M. tuberculosis infection, the causative agent of tuberculosis, and the leading cause of death due to infectious disease in the world today. As the premise behind vaccines is to train the immune system to recognize pathogens (via antigen presentation) and to quickly respond, information gained from the studies described herein can be immediately applied to vaccine design for M. tuberculosis as well as for other pathogens.
Publications:

1) Publications derived from this project:

Chang, ST, Ghosh, D, Kirschner, D and Linderman, JL. Peptide length-based prediction of peptide-MHC class II binding, (in revisions with Bioinformatics) June 2006.

Kirschner, DE, Chang, S, Riggs, T, Perry, N and Linderman JJ. Toward a multi-scale model of antigen presentation in immunity, In: Immunological Reviews. Eds: J. Mata and J. Cohen (in press) 2006.

Kirschner, D. The Multi-scale immune response to pathogens: M. tuberculosis as an example, In In Silico Immunology, edited by J. Timmis and D. Flower, Springer, NY (in press) 2006.

2) Publications related to this project:

Jose L. Segovia-Juarez, Suman Ganguli, and Denise Kirschner, Identifying control mechanism of granuloma formation during M. tuberculosis infection using an agent based model, Journal of Theoretical Biology. 231, Issue 3, Pages 357-376 2004.

Stewart T. Chang, Jennifer J. Linderman, and Denise E. Kirschner A role for multiple mechanisms in the inhibition of MHC class II- mediated antigen presentation by Mycobacterium tuberculosis, Proceedings of the National Academy of Sciences, USA, pps. 4530-4535 March 22, 2005 vol. 102 no. 12, 2005

David Gammack, Jose L. Segovia-Juarez, Suman Ganguli, Simeone Marino, and Denise Kirschner, Understanding the Immune Response in Tuberculosis Using Different Mathematical Models and Biological Scales, SIAM Journal of Multiscale Modeling and Simulation, Vol. 3, No. 2, pp. 312-345, 2005

M. Miller, A. Hejazi, S. Wei, M. Cahalan, and I. Parker, T cell repertoire scanning is promoted by dynamic dendritic cell behavior and random T cell motility in the lymph node, Proc Natl Acad Sci, vol. 101, pp. 9981003, 2004.

M. Miller, O. Safrina, I. Parker, and M. Cahalan, Imaging the single cell dynamics of CD4 T cell activation by dendritic cells in lymph nodes, J Exp Med, vol. 200, pp. 847856, 2004.

M. Miller, S.Wei, M. Cahalan, and I. Parker, Autonomous T cell trafficking examined in vivo with intravital two-photon microscopy, Proc Natl Acad Sci, vol. 100, pp. 26042609, 2003.

Singer, D.F., and J.J. Linderman, Antigen Processing and Presentation: How Can Foreign Antigen be Recognized in a Sea of Self Proteins, J. Theor. Biol. 151: 383-404, 1991.


Modeling Methods and Tools:

Ordinary Differential Equations (several non-linear types, all continuous, determistic approaches) and Agent-based Model (stochastic, discrete approach)
Software Development: Languages and Tools:

C++/C OOP, JAVA
Framework / Sharing Environment:

Open source software used in the lab, not currently involved in development frameworks.

http://malthus.micro.med.umich.edu/MSM/shareware


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Phone/Fax: (734) 647-7723