Tajie H. Harris


Primary Appointment

Associate Professor, Neuroscience


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

Research Disciplines

Biotechnology, Immunology, Infectious Diseases/Biodefense, Microbiology, Neuroimmunology, Neuroscience

Research Interests

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.


  • Basic Cardiovascular Research Training Grant
  • Biodefense & Infectious Diseases Short-Term Training to Increase Diversity in Biomedical Sciences
  • Biotechnology Training Grant
  • Global Biothreats Training Program
  • Infectious Diseases Training Program
  • Interdisciplinary Training Program in Immunology
  • Predoctoral Training in Neuroscience

Selected Publications

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, 2019; J Immunol. 202(6) 1755-1766. PMID:

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, 2018; Nat Neurosci. 21(10) 1380-1391. PMID:

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, 2018; J Exp Med. 215(7) 1789-1801. PMID:

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, 2017; J Immunol. 198(10) 4054-4061. PMID:

Louveau A, Smirnov I, Keyes TJ, Eccles JD, Rouhani SJ, Peske JD, Derecki NC, Castle D, Mandell JW, Lee KS, Harris TH, Kipnis J, Structural and functional features of central nervous system lymphatic vessels., 2015; Nature. () . PMID: 26030524 | PMCID: PMC4506234

Banigan EJ, Harris TH, Christian DA, Hunter CA, Liu AJ, Heterogeneous CD8+ T cell migration in the lymph node in the absence of inflammation revealed by quantitative migration analysis., 2015; PLoS computational biology. 11(2) e1004058. PMID: 25692801 | PMCID: PMC4334969

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, 2015; PLoS Comput Biol. 11(2) e1004058. PMID:

Louveau A., Harris T. H., Kipnis J., Revisiting the Mechanisms of CNS Immune Privilege, 2015; Trends Immunol. 36(10) 569-577. PMID:

Harris TH, Banigan EJ, Christian DA, Konradt C, Tait Wojno ED, Norose K, Wilson EH, John B, Weninger W, Luster AD, Liu AJ, Hunter CA, Generalized Lévy walks and the role of chemokines in migration of effector CD8+ T cells., 2012; Nature. 486(7404) 545-8. PMID: 22722867 | PMCID: PMC3387349

Norose K, Kikumura A, Luster AD, Hunter CA, Harris TH, CXCL10 is required to maintain T-cell populations and to control parasite replication during chronic ocular toxoplasmosis., 2010; Investigative ophthalmology & visual science. 52(1) 389-98. PMID: 20811054 | PMCID: PMC3053287