Thesis Jet van den Dijssel

On 10 July 2025 (1:00 PM) Sanquin researcher Jet van den Dijssel expects to defend her PhD thesis ‘SARS-CoV-2-specific CD8+ T cell responses in healthy and immunocompromised individuals‘ at the University of Amsterdam

Promotor: Prof RAW van Lier MD PhS
Copromotor: CE van de Sandt PhD

Venue: Agnietenkapel, Universiteit van Amsterdam

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abstract

CD8⁺ T cells are essential for antiviral immunity, reducing disease severity by recognizing and targeting a broad range of virus-derived epitopes. This thesis identified highly conserved SARS-CoV-2-specific CD8⁺ T cell epitopes to study the role of CD8⁺ T cells in healthy and immunocompromised individuals. SARS-CoV-2 infection induced robust virus-specific CD8⁺ T cell responses exhibiting a central memory phenotype, independent of age and/or latent cytomegalovirus. Although the immunodominant SARS-CoV-2-specific CD8⁺ T cell epitopes were mostly derived from non-spike proteins post-infection, spike-specific responses were boosted after mRNA vaccination while non-spike responses remained stable. In a cohort of autoimmune disease patients, including inflammatory bowel disease (IBD), multiple sclerosis (MS), and rheumatoid arthritis patients (RA), we assessed the impact of immunosuppressive therapies on vaccine-induced immunity. Anti-CD20-treated MS patients showed impaired humoral responses, which correlated with the serum concentrations of anti-CD20, but preserved CD8⁺ T cell responses. Methotrexate-treated RA patients exhibited diminished T cell activation, suggesting delayed or compromised immunity. TNF inhibitor-treated IBD patients mounted strong spike-specific central memory CD8⁺ T cell responses, comparable to those in untreated and healthy controls. To prepare for emerging viruses, designing vaccines that induce broad and long-lasting immune responses, while optimizing vaccination timing with immunosuppressive therapies, may enhance immunity in healthy and immunocompromised individuals. Additionally, novel techniques characterizing the functionality of epitope-specific CD8⁺ T cells are valuable to understand which epitopes are important for optimal immunity. Overall, this thesis expands our understanding of SARS-CoV-2-specific CD8⁺ T cells, underscoring the importance of their conserved immunity in healthy and vulnerable populations.

Chapters

Chapter 1

General introduction

Chapter 2

 Parallel detection of SARS-CoV-2 epitopes reveals dynamic immunodominance profiles of CD8+ T memory cells in convalescent COVID-19 donors abstract

Chapter 3

Age and latent cytomegalovirus infection do not affect the magnitude of de novo SARS-CoV-2-specific CD8+ T cell responses abstract

Chapter 4

mRNA-1273 vaccinated inflammatory bowel disease patients receiving TNF inhibitors develop broad and robust SARS-CoV-2-specific CD8+ T cell responses abstract

Chapter 5

Immune dynamics in SARS-CoV-2 experienced immunosuppressed rheumatoid arthritis or multiple sclerosis patients vaccinated with mRNA-1273 abstract

Chapter 6

T cell activation markers CD38 and HLA-DR indicative of non-seroconversion in anti-CD20-treated patients with multiple sclerosis following SARS-CoV-2 mRNA vaccination

Chapter 7

Linking epitope-specific T cell receptors to IFNγ secretion using nanovial technology

Chapter 8

General discussion

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Download thesis from university repository (when available)

Cover PhD thesis Jet van den Dijssel