New thesis advances knowledge of immune response after vaccination
David Wulliman from Center for Infectious Medicine (CIM), at the Departmet of Medicine, Huddinge (MedH) is defending his thesis titled "T Cell Immunity Induced by SARS-CoV-2 and Flavivirus Vaccination", on 23 May, 2025. Main supervisor is Hans-Gustaf Ljunggren (MedH).
What is the main focus of your thesis?
The main focus of my thesis is the T cell response after vaccination against SARS-CoV-2 and flaviviruses.
Which are the most important results?
In studies I and II could we show that patients with chronic lymphocytic leukemia (CLL) developed T cell responses after COVID-19 mRNA vaccination, but to a lesser degree compared to healthy controls. We measured the immune response in a CLL cohort which had hybrid immunity from previous infection and COVID-19 vaccination and could detect an increased T cell response. These CLL patients also developed T cell responses equally to the ancestral strain (Wuhan) and Omicron, suggesting that exposure from the beginning of the pandemic could also protect against significantly mutated variants such as Omicron.
In study III, we could identify a link between previous human coronavirus OC43 infection and pre-existing immunity to SARS-CoV-2 in unexposed individuals.
In study IV, we compared the T cell response after co-administration of different flavivirus vaccines with single vaccinated individuals and could not detect any meaningful differences. From this study, we conclude that these flavivirus vaccines induces T cell responses that is specific with limited cross-reactivity, which is neither enhanced nor diminished by co-administration – which is a safe vaccine strategy for these flavivirus vaccines.
How can this new knowledge contribute to the improvement of people’s health?
This knowledge improves our understanding of the role of T cells in the immune response to vaccination in healthy and immunocompromised individuals. This knowledge can be used to improve current vaccine strategies and inform new vaccine development which remains one of our most important way to prevent infectious disease.
What are your future ambitions?
I want to continue research as immunologist and improve our understanding of the immune response to vaccination. It is an incredibly interesting field with importance to society and global health.
Dissertation
Friday, 23 May at 13:00, 9Q Månen, ANA Futura.
Thesis
T Cell Immunity Induced by SARS-CoV-2 and Flavivirus Vaccination.