Mario Ostrowski

Department of Medicine


St. Michael’s Hospital: Unity Health Toronto
30 Bond St., HIV Clinic, 4th Floor, CC Wing, Toronto, Ontario Canada M5B 1W8
Research Interests
Infectious Diseases & Immunopathology, Molecular & Cell Biology
Appointment Status

Mario Ostrowski is a professor of Medicine, Immunology and pathobiology and lab medicine at University of Toronto and also is a consultant infectious diseases clinician at St. Michael's Hospital in Toronto, Canada.

His interests include:

  • studies on T cell immunoregulation in HIV and HCV infection
  • molecular adjuvants for vaccination
  • pDC-virus interactions
  • the role of endogenous retroviruses in HIV infection.


Research Synopsis


My research focuses on understanding the immunopathogenesis of chronic persistent virus infections in humans with a focus on two socially important virus infections:

  1. HIV (Human Immunodeficiency Virus) and
  2. HCV (Hepatitis C Virus) infection

Both are almost certain to supersede small pox infection in terms of global human morbidity and mortality.

The research explores host and parasite (evasion) immunologic mechanisms that lead to viral persistence with the goal of defining new immunotherapies and vaccines in HIV and HCV infection.

The work is translational and utilizes human clinical samples at the bedside from individuals who are well characterized in terms of their ability to control virus and associated pathology (CD4 count for HIV, chronic hepatitis for HCV), which are then intensively studied at the bench using the disciplines of cellular and molecular immunology and virology.

The work is multi-disciplinary, in which collaborations are developed between clinicians, epidemiologists, virologists, immunologists and bioinformatics biologists.

Specific interests include studies on T cell immunoregulation in HIV and HCV infection, molecular adjuvants for vaccination, pDC-virus interactions, and the role of endogenous retroviruses in HIV infection.


Recent Publications


Huang YH, Zhu C, Kondo Y, Anderson AC, Gandhi A, Russell A, Dougan SK, Petersen BS, Melum E, Pertel T, Clayton KL, Raab M, Chen Q, Beauchemin N, Yazaki  PJ, Pyzik M, Ostrowski MA, Glickman JN, Rudd CE, Ploegh HL, Franke A, Petsko GA,  Kuchroo VK, Blumberg RS. CEACAM1 regulates TIM-3-mediated tolerance and exhaustion. Nature. 2015 Jan 15;517(7534):386-90. doi: 10.1038/nature13848. Epub  2014 Oct 26. PubMed PMID: 25363763

Clayton KL, Douglas-Vail MB, Rahman AK, Medcalf KE, Xie IY, Chew GM, Tandon R, Lanteri MC, Norris PJ, Deeks SG, Ndhlovu LC, Ostrowski MA. Soluble T Cell Immunoglobulin Mucin Domain 3 Is Shed from CD8+ T Cells by the Sheddase ADAM10, Is Increased in Plasma during Untreated HIV Infection, and Correlates with HIV Disease Progression. J Virol. 2015 Apr 1;89(7):3723-36. doi: 10.1128/JVI.00006-15. Epub 2015 Jan 21. PubMed PMID: 25609823.                                                                                          

Clayton KL, Haaland MS, Douglas-Vail MB, Mujib S, Chew GM, Ndhlovu LC, Ostrowski MA. T cell Ig and mucin domain-containing protein 3 is recruited to the immune synapse, disrupts stable synapse formation, and associates with receptor phosphatases. J Immunol. 2014 Jan 15;192(2):782-91. doi: 10.4049/jimmunol.1302663. Epub 2013 Dec 13. PubMed PMID: 24337741.

Liu J, Zhan W, Kim CJ, Clayton K, Zhao H, Lee E, Cao JC, Ziegler B, Gregor A,  Yue FY, Huibner S, MacParland S, Schwartz J, Song HH, Benko E, Gyenes G, Kovacs C, Kaul R, Ostrowski M. IL-10-producing B cells are induced early in HIV-1 infection and suppress HIV-1-specific T cell responses. PLoS One. 2014 Feb 21;9(2):e89236. doi: 10.1371/journal.pone.0089236. eCollection 2014. PubMed PMID: 24586620; PubMed Central PMCID: PMC3931714.

R. Brad Jones, Haihan Song, Yang Xu, Keith Garrison, Anton Buzdin, Naveed Anwar, Diana Hunter, Shariq Mujib, Vesna Mihajlovic, Eric Martin, Erika Lee, Monka Kuciak, Rui Andre Saraiva Raposo, Ardalan Bozorgzad, Duncan Meiklejohn, Lishomwa Ndhlovu, Douglas Nixon, and Mario Ostrowski. LINE-1 Retrotransposable Element DNA Accumulates in HIV-1-infected Cells. J of Virology, 2013 Dec;87(24):13307-20. doi: 10.1128/JVI.02257-13. Epub 2013 Oct 2. PMID:24089548

Rahman AN, Clayton K, Mujib S, Fong IW, Ostrowski MA (2012) TIM-3 and Its Immunoregulatory Role in HIV Infection. J Clin Cell Immunol S7:007. doi:10.4172/2155-9899.S7-007