Prof. Okumura studies interactions between bacterial pathogens and human immune cells at the cellular level.
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Research Description
My research focuses on host-pathogen interactions, specifically the cellular responses of immune cells to infectious bacteria. We study Group A Streptococcus (GAS; Streptococcus pyogenes; strep), a bacterial pathogen that causes infections ranging from strep throat to sepsis and toxic shock. GAS is a human-specific pathogen and therefore has a variety of mechanisms to survive in our bodies, including defenses against our immune cells. We study how processes of the host cell change with infection, such as reactive oxygen species generation, lysosomal digestion, extracellular protein secretion, and exosome generation. Work in my lab also examines potential virulence factors of these bacterial pathogens and their contribution to resistance to the innate immune and cellular responses of the host.
Students learn:
- Mammalian cell culture
- Microbial culture and techniques
- Biosafety Level 2 lab skills
- Cellular activity assays
- Western blot
- Immunofluorescence and confocal microscopy
Courses
Introduction to Cell and Molecular Biology (Bio 130)
Cell Biology (Bio 226)
Microbial Pathogenesis (Bio 336)
Student Research Opportunities
We are always looking for students to join the lab. Please look at our webpage to learn about our research, including general expectations about working in the lab. After that, please schedule an appointment to speak with me!
Select Publications
Bold = undergraduate student authors; *equal authorship
Quezada A, Lord K, Alcantara C, Delahunty C, Kim K, Okamoto O, Yates JR III, Okumura CY. Lysosomal permeabilization by Group A Streptococcus releases proteins into the macrophage cytosol. bioRxiv; 2025 [Preprint]. Oct 25, 2025. doi:
Nishioka ST*, Snipper J*, Lee J, Schapiro J, Zhang RZ, Abe H, Till A, Okumura CY. Group A Streptococcus Induces Lysosomal Dysfunction in THP-1 Macrophages. Infect Immun. 2024 Jun 11;92(6):e0014124. doi: 10.1128/iai.00141-24. Epub 2024 May 9. PMID: 38722166.
Wilde S, Dash A, Johnson A, Mackey K, Okumura CY, LaRock CN. Detoxification of reactive oxygen species by the hyaluronic acid capsule of group A Streptococcus. Infect Immun. 2023 Nov 16;91(11):e0025823. doi: 10.1128/iai.00258-23. Epub 2023 Oct 24. PMID: 37874162.
Clark M, Kim J, Etesami N, Shimamoto J, Whalen RV, Martin G, Okumura CY. Group A Streptococcus Prevents Mast Cell Degranulation to Promote Extracellular Trap Formation. Front Immunol. 2018 Feb 27;9:327. doi: 10.3389/fimmu.2018.00327. eCollection 2018. PMID: 29535718
D枚hrmann S, Anik S, Olson J, Anderson, EL, Etesami N, No H, Snipper J, Nizet V, Okumura CY.A Role for Streptococcal Collagen-Like Protein 1 (Scl-1) in M1T1 Group A Streptococcus Resistance to Neutrophil Extracellular Traps. Infect Immun. 2014 Oct;82(10):4011-20. PMID: 25024366