Replicon vaccines to combat avian infectious diseases

Summary

This thesis addresses the critical challenges faced by the poultry industry due to infectious diseases, emphasizing the global demand for animal-based food products. The focus of this thesis is on developing a novel self-amplifying RNA replicon platform, specifically utilizing the bird-adapted Tembusu virus (TMUV). The TMUV replicon system, derived from a contemporary isolate, exhibited superior viral propagation compared to conventional TMUV isolates in various cell lines. Expression kinetics and cytopathic effects of TMUV replicon-mediated transgene expression were analyzed, demonstrating its potential to produce virus-derived transgenes such as haemagglutinin (AIV), spike (IBV), and nucleocapsid protein (IBDV). In vivo evaluations with 1-day-old chickens showed that TMUV replicon RNA and DNA-launched replicon (DREP) modalities induced specific humoral responses against infectious bursal disease virus (IBDV). The study suggests the suitability of TMUV replicon platforms for poultry vaccination, urging further investigations into protective immunity and replication modalities' impact on seroconversion in chickens. Overall, the findings depicted in this thesis contribute to advancing a comprehensive repertoire of replicon modalities for potential poultry vaccination strategies.