Michael D. Gunn, MD

Department / Division:
Medicine / Cardiovascular Medicine

Address:
DUMC 3547
Durham, NC 27710

Appointment Telephone:
Not accepting patients

Office Telephone:
919-681-0840

Fax Telephone:
919-684-8591

• MD, University of Texas Southwestern Medical School, 1983

• Internal Medicine, Parkland Memorial Hospital (Texas), 1986

• Cardiology, University of California, San Francisco, 1989

Clinical Interests:
Immunologic aspects of cardiovascular diseases

Research Interests:
The focus of our work is on understanding how dendritic cells and dendritic cell activation initiate and regulate immune responses.  Our ultimate aim is to apply this knowledge to the development of vaccines and immunotherapeutics for human use.  

Lab History

The lab started with our discovery of the lymphoid chemokines, which regulate the migration of lymphocytes and dendritic cells to and within secondary lymphoid organs.  We identified CCL21 as the chemokine that mediates the entry of naïve T cells and dendritic cells into lymph nodes.  We identified CXCL13 as the chemokine that mediates the entry of B cells into lymphoid follicles.  We determined that the murine plt mutation is due to a loss of CCL21 expression in lymphoid organs and that this leads to major defects in dendritic cell migration.

Our focus then shifted to understanding how specific cell types, primarily dendritic cells, and cell migration events regulate immune responses.  We were the first to describe murine plasmacytoid dendritic cells and the first to determine the full extent of monocyte-derived dendritic cell development during inflammation. Our current work continues these basic studies while applying our findings to models of human disease.

Current Research

Understanding how dendritic cells regulate the strength, duration, and character  of immune response – Lymph nodes contain six distinct DC populations, including inflammatory monocyte-derived dendritic cells.  Through the use of extensive flow cytometric analysis and chemokine-deficient mice, we are determining how these DC populations act to regulate innate and adaptive immune responses.  Current projects include the identification of DC populations that induce Th1 and Th17 T cell polarization after immunization or acute infection, the identification of signals that regulate these DC phenotypes, and determining how DC regulate innate responses such as neutrophil accumulation.  Once these pathways are defined in model systems, we examine how they contribute to the pathophysiology of specific infections and diseases.

Mechanisms of pulmonary immune pathology – Using the techniques we developed to characterize lymph node DC subsets, we have recently identified the lung inflammatory cell populations that arise during influenza infection.  We have found that the CCR2-dependent accumulation of monocyte-derived DC and exudate macrophages is the cause of influenza-induced pulmonary immune pathology, morbidity, and mortality.  We are currently examining the role that specific lung inflammatory cell populations play in other types of lung injury such as ARDS and chemical exposure and determining if such injury can be prevented by the pharmacologic inhibition of inflammatory cell migration.

The immunobiology of atherosclerosis – As a cardiologist, I have a strong interest in the contribution of immune response to atherosclerosis.  We have determined that a population of resident “vascular” dendritic cells is present in the arteries of normal mice.  Interestingly, the distribution of the vDC exactly mirrors the pattern in which atherosclerotic lesions develop in ApoE-deficient mice.  Current studies seek to determine the activity of these vDC, their contribution to immune responses to atherosclerosis-associated antigens, and their contribution to atherosclerosis itself.  We are also examining when and where T cell responses to atherosclerosis-associated antigens arise, how these responses are regulated by specific dendritic cell populations, and the antigen specificity of atherosclerotic T cell responses.  

Development of recombinant antibodies – Our understanding of how immune responses are regulated at the DC level has direct applicability to the development of agents that can stimulate or inhibit specific immune responses.  Using a novel method to generate recombinant single chain antibodies, we have developed antibodies specific for several toll-like receptors (TLRs).  We are currently working on antibodies that can be used to diagnose infections by individual pathogens.

Representative Publications:
Nakano H, Lin KL, Yanagita M, Charbonneau C, Cook DN, Kakiuchi T, Gunn MD. Blood-derived inflammatory dendritic cells in lymph nodes stimulate acute T helper type 1 immune responses. Nat Immunol. 2009 Apr;10(4):394-402. (2009) Abstract

Chen YH, Lipes BD, Kenan DJ, Staats HF, Gunn MD. Identification of recombinant antibodies against multiple distinct toll-like receptors by homolog mining a single immune scFv phage library. J Immunol Methods. 2009 Jan 30;340(2):144-53. (2009) Abstract

Lipes BD, Chen YH, Ma H, Staats HF, Kenan DJ, Gunn MD. An entirely cell-based system to generate single-chain antibodies against cell surface receptors. J Mol Biol. 2008 May 30;379(2):261-72. (2008) Abstract

Lin KL, Suzuki Y, Nakano H, Ramsburg E, Gunn MD. CCR2+ monocyte-derived dendritic cells and exudate macrophages produce influenza-induced pulmonary immune pathology and mortality. J Immunol. 2008 Feb 15;180(4):2562-72. (2008) Abstract

Nakano H, Yanagita M, Gunn MD. CD11c⁺ B220⁺ Gr-1⁺ cells in mouse lymph nodes and spleen display characteristics of plasmacytoid dendritic cells.  J Exp Med.  2001 Oct 15;194(8):1171-8. (2001) Abstract

Mori S, Nakano H, Aritomi K, Wang CR, Gunn MD, Kakiuchi T. Mice lacking expression of the chemokines CCL21-ser and CCL19 (plt mice) demonstrate delayed but enhanced T cell immune responses.  J Exp Med.  2001 Jan 15;193(2):207-18. (2001) Abstract

Gunn MD, Kyuwa S, Tam C, Kakiuchi T, Matsuzawa A, Williams LT, Nakano H. Mice lacking expression of secondary lymphoid organ chemokine have defects in lymphocyte homing and dendritic cell localization.  J Exp Med.  1999 Feb 1;189(3):451-60. (1999) Abstract

Gunn MD, Tangemann K, Tam C, Cyster JG, Rosen SD, Williams LT. A chemokine expressed in lymphoid high endothelial venules promotes the adhesion and chemotaxis of naive T lymphocytes.  Proc Natl Acad Sci U S A.  1998 Jan 6;95(1):258-63. (1998) Abstract

Gunn MD, Ngo VN, Ansel KM, Ekland EH, Cyster JG, Williams LT. A B-cell-homing chemokine made in lymphoid follicles activates Burkitt's lymphoma receptor-1.  Nature.  1998 Feb 19;391(6669):799-803. (1998) Abstract