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Greg Sempowski

Greg Sempowski

Senior Infectious Disease Investigator


PhD, Microbiology and Immunology, University of Rochester School of Medicine and Dentistry
MS, Microbiology and Immunology, University of Rochester School of Medicine and Dentistry
BS, Biology, Syracuse University


Greg Sempowski has over 25 years of experience working in the emerging infectious disease and biodefense community to develop diagnostics, vaccines, and medical countermeasures to halt infectious disease outbreaks of global concern. He is highly collaborative and skilled in pre-clinical study design and execution to investigate host immune response and pathogen challenge response in a wide range of species (e.g. mice, pigs, rats, hamsters, ferrets, non-human primates, and humans).

Dr. Sempowski joined RTI in 2022 from Duke University School of Medicine/Human Vaccine Institute. Currently, he is the contact principal investigator for the Center for Research in Emerging Infectious Disease (CREID) – Coordination Center. CREID is a global network of emerging infectious disease research centers situated in regions around the world where emerging and reemerging infectious diseases outbreaks are likely to occur. The multidisciplinary research teams and the Coordinating Center have prospectively developed a framework and scalable infrastructure to respond quicky and effectively to future outbreaks.

The SARS-CoV-2 pandemic, as well as the potential of future pandemics based on estimates of undiscovered zoonotic infections, has brought to the forefront urgency and necessity for rapid development of pandemic countermeasures. With funding from the Defense Advanced Research Projects Agency (DARPA) Pandemic Prevention Program, Dr. Sempowski and his collaborative team at Duke developed an end-to-end platform to rapidly isolate and propagate viral pathogens, isolate human neutralizing antibody sequences, develop effective approaches to deliver neutralizing antibodies as nucleic acids (i.e. mRNA), and develop good manufacturing practices for final producing drug product to submit to the FDA for Phase I approval within 60 days of receiving an outbreak blood specimen.

Before joining RTI, Dr. Sempowski was trained in the areas of inflammation, wound healing, and host response (innate and adaptive immunology) at the University of Rochester. During his graduate work, he contributed substantially to the field of lung inflammation and fibrosis by defining the roles of pulmonary fibroblast heterogeneity and CD40/CD40L signaling in regulating normal and pathogenic lung inflammation.

During his postdoctoral training at Duke University, Dr. Sempowski focused on human immunology and more specifically thymic function and immune reconstitution in settings of immune deficiency. As an early-stage investigator at Duke, Dr. Sempowski made significant contributions to to the field of thymus involution, T cell homeostasis and immune aging.  Most notably, he described an active cytokine-driven mechanism of age-induced thymus gland involution. Blockade of this mechanism could have a significant impact on immune reconstitution and peripheral T cell immune function in older adults. His laboratory developed a molecular assay system to monitor thymic output in mice, which resulted in a U.S. patent. This system has become standard operating procedure for laboratories investigating thymus biology in mouse models.

During his early training and tenure on the faculty at Duke University, Dr. Sempowski published over 180 peer-reviewed research articles, scientific reviews and book chapters, and is internationally recognized as a thought leader in thymic aging, immune senescence, high containment lab and animal research and pandemic preparedness/outbreak response and countermeasure development.

Dr. Sempowski is a member of the American Association of Immunologists and the Federation of American Societies for Experimental Biologists. He was also a member of the International Society of Analytical Cytometry.

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