Mario Ostrowski

MD, FRCP

Scientist

Biography

My current research interests focus on the immunopathogenesis of Human Immunodeficiency Virus (HIV) /Acquired Immune Deficiency Syndrome (AIDS) and Hepatitis C Virus (HCV) and other virus infections including SARS-CoV-2. We are interested in understanding why chronic virus infections persist in the host. Current work is divided along the following lines:

  1. Examination of T cell immune response to HIV and HCV infection.
  2. Therapeutic and preventive vaccine strategies
  3. immunomodulation during virus infections

Recent Publications

  1. Samaan, P, Korosec, CS, Budylowski, P, Chau, SLL, Pasculescu, A, Qi, F et al.. mRNA vaccine-induced SARS-CoV-2 spike-specific IFN-γ and IL-2 T-cell responses are predictive of serological neutralization and are transiently enhanced by pre-existing cross-reactive immunity. J Virol. 2025; :e0168524. doi: 10.1128/jvi.01685-24. PubMed PMID:39887249 .
  2. Naghibosadat, M, Babuadze, GG, Pei, Y, Hurst, J, Salvant, E, Gaete, K et al.. Vaccination against SARS-CoV-2 provides low-level cross-protection against common cold coronaviruses in mouse and non-human primate animal models. J Virol. 2025; :e0139024. doi: 10.1128/jvi.01390-24. PubMed PMID:39817773 .
  3. Liu, J, Wang, L, Kurtesi, A, Budylowski, P, Potts, KG, Menon, H et al.. A bivalent COVID-19 mRNA vaccine elicited broad immune responses and protection against Omicron subvariants infection. NPJ Vaccines. 2025;10 (1):4. doi: 10.1038/s41541-025-01062-8. PubMed PMID:39788981 PubMed Central PMC11718203.
  4. Hurst, JR, Naghibosadat, M, Budowski, P, Liu, J, Samaan, P, Budiman, F et al.. Comparison of a SARS-CoV-2 mRNA booster immunization containing additional antigens to a spike-based mRNA vaccine against Omicron BA.5 infection in hACE2 mice. PLoS One. 2024;19 (12):e0314061. doi: 10.1371/journal.pone.0314061. PubMed PMID:39625929 PubMed Central PMC11614295.
  5. Grundy, EE, Shaw, LC, Wang, L, Lee, AV, Argueta, JC, Powell, DJ Jr et al.. A T cell receptor specific for an HLA-A*03:01-restricted epitope in the endogenous retrovirus ERV-K-Env exhibits limited recognition of its cognate epitope. Mob DNA. 2024;15 (1):19. doi: 10.1186/s13100-024-00333-w. PubMed PMID:39385229 PubMed Central PMC11462856.
  6. Grundy, EE, Shaw, LC, Wang, L, Powell, DJ, Ostrowski, M, Jones, RB et al.. Limited Immunogenicity of an HLA-A*03:01-restricted Epitope of Erv-k-env in Non-hiv-1 Settings: Implications for Adoptive Cell Therapy in Cancer. Res Sq. 2024; :. doi: 10.21203/rs.3.rs-4432372/v1. PubMed PMID:38854052 PubMed Central PMC11160923.
  7. Costiniuk, CT, Lee, T, Singer, J, Galipeau, Y, Arnold, C, Langlois, MA et al.. Correlates of Breakthrough SARS-CoV-2 Infections in People with HIV: Results from the CIHR CTN 328 Study. Vaccines (Basel). 2024;12 (5):. doi: 10.3390/vaccines12050447. PubMed PMID:38793698 PubMed Central PMC11125718.
  8. Budylowski, P, Chau, SLL, Banerjee, A, Guvenc, F, Samson, R, Hu, Q et al.. A Significant Contribution of the Classical Pathway of Complement in SARS-CoV-2 Neutralization of Convalescent and Vaccinee Sera. J Immunol. 2024;212 (12):1922-1931. doi: 10.4049/jimmunol.2300320. PubMed PMID:38683124 .
  9. Reiter, L, Greffrath, J, Zidel, B, Ostrowski, M, Gommerman, J, Madhi, SA et al.. Comparable safety and non-inferior immunogenicity of the SARS-CoV-2 mRNA vaccine candidate PTX-COVID19-B and BNT162b2 in a phase 2 randomized, observer-blinded study. Sci Rep. 2024;14 (1):5365. doi: 10.1038/s41598-024-55320-1. PubMed PMID:38438427 PubMed Central PMC10912344.
  10. Tan, DHS, Pico Espinosa, O, Matelski, J, Khera, SS, Qamar, A, Persaud, R et al.. Longitudinal Analysis of Mpox Virus DNA Detectability From Multiple Specimen Types During Acute Illness: A Cohort Study. Open Forum Infect Dis. 2024;11 (2):ofae073. doi: 10.1093/ofid/ofae073. PubMed PMID:38390463 PubMed Central PMC10883290.
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Affiliations & Other Activities

  • Infectious Disease Consultant, St. Michael’s Hospital
  • Professor, Department of Medicine, Immunology, Lab Medicine, Pathobiology, University of Toronto