PhD defence
Cellular immune profiles of Africans and Europeans in the context of vaccination and infectious diseases
- Y.D. Mouwenda
- Date
- Wednesday 7 May 2025
- Time
- Location
-
Academy Building
Rapenburg 73
2311 GJ Leiden
Supervisor(s)
- Prof.dr. M. Yazdanbakhsh
- dr. S.P. Jochems
- dr. M. Massinga Loembe
Summary
Infectious diseases remain a major public health challenge and vaccines are key to prevention. However, vaccine efficacy varies across populations often due to environmental and genetic factors. For example, in helminth-endemic regions, immune suppression may reduce vaccine effectiveness. This thesis investigates immune responses to new vaccine candidates and uses mass cytometry to identify immune markers that could help optimize vaccine strategies. For instance, in Chapter 2, Na-GST-1, a hookworm vaccine candidate, was found to induce TNF-producing effector-memory CD4 T cells expressing CD40L and CTLA-4. Since CTLA-4 suppresses immune responses, its blockade increased cytokine production even prior to vaccination, suggesting an inherent inhibitory effect at baseline. Also, in Chapter 3, malaria immunity was assessed in German volunteers vaccinated with PfSPZ-CVac (a live, chloroquine-attenuated Plasmodium falciparum sporozoite vaccine) and in naturally immune Gabonese individuals. Elevated levels of CD56+ CD8 T cells and CD161+ CD4 T cells were associated with protection in both groups, with CD161+ CD4 T cells potentially linked to immunity following repeated malaria exposure. As most vaccines are administered during the first year of life, Chapters 4 and 5 investigate cord blood responses in Gabonese populations and the impact of maternal infections. These studies uncovered environmental influences on early immune development, specifically differences in innate immune cells (NK cells, ILCs, monocytes) and in hematopoietic and progenitor stem cells, depending on maternal infection status. Overall, our findings suggest that environmental exposures shape immune responses from birth to adulthood, with significant implications for vaccine efficacy.
PhD dissertations
Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.
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