A multiantigenic Orf virus-based vaccine efficiently protects hamsters and nonhuman primates against SARS-CoV-2.

Among the common strategies to design next-generation COVID-19 vaccines is broadening the antigenic repertoire thereby aiming to increase efficacy against emerging variants of concern (VoC). This study describes a new Orf virus-based vector (ORFV) platform to design a multiantigenic vaccine targeting SARS-CoV-2 spike and nucleocapsid antigens. Vaccine candidates were engineered, either expressing spike protein (ORFV-S) alone or co-expressing nucleocapsid protein (ORFV-S/N).

Orf Virus-Based Vectors Preferentially Target Professional Antigen-Presenting Cells, Activate the STING Pathway and Induce Strong Antigen-Specific T Cell Responses.

Background: Orf virus (ORFV)-based vectors are attractive for vaccine development as they enable the induction of potent immune responses against specific transgenes. Nevertheless, the precise mechanisms of immune activation remain unknown. This study therefore aimed to characterize underlying mechanisms in human immune cells.

A Novel Orf Virus D1701-VrV-Based Dengue Virus (DENV) Vaccine Candidate Expressing HLA-Specific T Cell Epitopes: A Proof-of-Concept Study.

Although dengue virus (DENV) affects almost half of the world's population there are neither preventive treatments nor any long-lasting and protective vaccines available at this time. The complexity of the protective immune response to DENV is still not fully understood. The most advanced vaccine candidates focus specifically on humoral immune responses and the production of virus-neutralizing antibodies.

-Based Vaccine Vector D1701-V Induces Strong CD8+ T Cell Response against the Transgene but Not against ORFV-Derived Epitopes.

The potency of viral vector-based vaccines depends on their ability to induce strong transgene-specific immune response without triggering anti-vector immunity. Previously, (ORFV, ) strain D1701-V was reported as a novel vector mediating protection against viral infections. The short-lived ORFV-specific immune response and the absence of virus neutralizing antibodies enables repeated immunizations and enhancement of humoral immune responses against the inserted antigens.