Tajie H. Harris


  • BS, Bemidji State University
  • PhD, University of Wisconsin-Madison
  • Postdoc, University of Pennsylvania

Primary Appointment

  • Associate Professor, Neuroscience


Research Interest(s)

Immune response to infectious disease in the CNS

Research Description

Toxoplasma gondii is an intracellular, protozoan parasite that infects approximately one-third of the world population. The parasite can be acquired congenitally or in adults, through the ingestion of contaminated food or water. Acute infection with T. gondii leads to systemic disease that is largely controlled by the cytokine, IFN-g. Despite this, the parasite persists in several tissues, including the brain and retina, where an ongoing T cell-mediated immune response is necessary to limit parasite replication. The vast majority of infections are asymptomatic, but suppression of T cell function can lead to severe toxoplasmic encephalitis and/or retinochoroiditis. While the importance of T cells in controlling T. gondii in the brain and eye has been demonstrated, research in the Harris laboratory aims to identify factors within immune-privileged tissues that influence local resistance to T. gondii.

The Harris laboratory will use MP microscopy and other cutting-edge techniques to provide insight into the orchestration of local immune responses in the brain and retina. The laboratory is currently focusing on the role of microglia and macrophages in the control of infection in the brain. Several projects focus on the role of alarmins, which are molecules that are expressed by healthy cells and released into the tissue environment in response to aberrant death or damage.

Selected Publications

  • Banigan E, Harris T, Christian D, Hunter C, Liu A. Heterogeneous CD8+ T cell migration in the lymph node in the absence of inflammation revealed by quantitative migration analysis. PLoS computational biology. 2015;11(2): e1004058. PMID: 25692801 | PMCID: PMC4334969
  • Louveau A, Smirnov I, Keyes T, Eccles J, Rouhani S, Peske J, Derecki N, Castle D, Mandell J, Lee K, Harris T, Kipnis J. Structural and functional features of central nervous system lymphatic vessels. Nature. 2015. PMID: 26030524 | PMCID: PMC4506234
  • Harris T, Banigan E, Christian D, Konradt C, Tait Wojno E, Norose K, Wilson E, John B, Weninger W, Luster A, Liu A, Hunter C. Generalized Lévy walks and the role of chemokines in migration of effector CD8+ T cells. Nature. 2012;486(7404): 545-8. PMID: 22722867 | PMCID: PMC3387349
  • Norose K, Kikumura A, Luster A, Hunter C, Harris T. CXCL10 is required to maintain T-cell populations and to control parasite replication during chronic ocular toxoplasmosis. Investigative ophthalmology & visual science. 2010;52(1): 389-98. PMID: 20811054 | PMCID: PMC3053287
  • Banigan E. J., Harris T. H., Christian D. A., Hunter C. A., Liu A. J.. Heterogeneous CD8+ T cell migration in the lymph node in the absence of inflammation revealed by quantitative migration analysis PLoS Comput Biol. 11(2): e1004058.
  • Louveau A., Harris T. H., Kipnis J.. Revisiting the Mechanisms of CNS Immune Privilege Trends Immunol. 36(10): 569-577.
  • Louveau A., Herz J., Alme M. N., Salvador A. F., Dong M. Q., Viar K. E., Herod S. G., Knopp J., Setliff J. C., Lupi A. L., Da Mesquita S., Frost E. L., Gaultier A., Harris T. H., Cao R., Hu S., Lukens J. R., Smirnov I., Overall C. C., Oliver G., Kipnis J.. CNS lymphatic drainage and neuroinflammation are regulated by meningeal lymphatic vasculature Nat Neurosci. 21(10): 1380-1391.
  • Norris G. T., Smirnov I., Filiano A. J., Shadowen H. M., Cody K. R., Thompson J. A., Harris T. H., Gaultier A., Overall C. C., Kipnis J.. Neuronal integrity and complement control synaptic material clearance by microglia after CNS injury J Exp Med. 215(7): 1789-1801.
  • O'Brien C. A., Batista S. J., Still K. M., Harris T. H.. IL-10 and ICOS Differentially Regulate T Cell Responses in the Brain during Chronic Toxoplasma gondii Infection J Immunol. 202(6): 1755-1766.
  • O'Brien C. A., Overall C., Konradt C., O'Hara Hall A. C., Hayes N. W., Wagage S., John B., Christian D. A., Hunter C. A., Harris T. H.. CD11c-Expressing Cells Affect Regulatory T Cell Behavior in the Meninges during Central Nervous System Infection J Immunol. 198(10): 4054-4061.