ISBN 9783843941099

978-3-8439-4109-9, Reihe Technische Chemie

David Wetzel
Establishment of a yeast-based virus-like particle platform for antigen display

104 Seiten, Dissertation Technische Universität Dortmund (2019), Softcover, A5

Zusammenfassung / Abstract

Vaccination is one of the most effective forms of medical intervention and plays a leading role in preventing infectious diseases in humans and animals. So-called chimeric virus-like particles (VLP) represent a novel and favorable class of subunit vaccines. On the surface of these non-infectious structures, antigenic protein or peptide epitopes derived from theoretically any pathogen can be displayed to improve their immunogenicity. However, finding an efficient production system and a VLP scaffold that allows stable incorporation of diverse, large foreign antigens are major challenges in this field.

In this thesis, a versatile platform for chimeric VLP development was established. The small surface protein (dS) of the duck hepatitis B virus was chosen as VLP scaffold and the yeast Hansenula polymorpha as expression host. Recombinant yeast strain generation strategies and analytics were developed and a total of 13 different antigens ranging from 11 kDa to 80 kDa derived from five different pathogens were successfully displayed on the dS-based VLP surface. This versatility is remarkable in the field of chimeric VLP development. As part of this study, it was demonstrated that a downstream process (DSP) approved for hepatitis B VLP vaccine production is principally applicable for the purification of chimeric dS-based VLP displaying different foreign antigens.

The last part of this thesis focused on improving the DSP for one type of the developed chimeric VLP. Modification of the individual purification steps in combination with the introduction of a precipitation step led to improved yields and similar product quality compared to the unmodified DSP. Most importantly, the costly and highly manual ultracentrifugation step which represents a common methodology in the field of VLP purification was avoided.

This study delivers a platform for chimeric VLP development, solves key challenges of the field and thus should be considered in the development of future vaccine candidates.