Immunization of pigs with an attenuated pseudorabies virus recombinant expressing the haemagglutinin of pandemic swine origin H1N1 influenza A virus

Abstract

Pigs can be severely harmed by influenza, and represent important reservoir hosts, in which new human pathogens such as the recent pandemic swine-origin H1N1 influenza A virus can arise by mutation and reassortment of genome segments. To obtain novel, safe influenza vaccines for pigs, and to investigate the antigen-specific immune response, we modified an established live-virus vaccine against Aujeszky's disease of swine, pseudorabies virus (PrV) strain Bartha (PrV-Ba), to serve as vector for the expression of haemagglutinin (HA) of swine-origin H1N1 virus. To facilitate transgene insertion, the genome of PrV-Ba was cloned as a bacterial artificial chromosome. HA expression occurred under control of the human or murine cytomegalovirus immediate early promoters (P-HCMV, P-MCMV), but could be substantially enhanced by synthetic introns and adaptation of the codon usage to that of PrV. However, despite abundant expression, the heterologous glycoprotein was not detectably incorporated into mature PrV particles. Replication of HA-expressing PrV in cell culture was only slightly affected compared to that of the parental virus strain. A single immunization of pigs with the PrV vector expressing the codon-optimized HA gene under control of P-MCMV induced high levels of HA-specific antibodies. The vaccinated animals were protected from clinical signs after challenge with a related swine-origin H1N1 influenza A virus, and challenge virus shedding was significantly reduced.

Viral vector-based influenza vaccines

“…Recombinant PrV expressing the NA gene derived from a swine A(H1N1) influenza virus only protected pigs to a limited extent. 129,130 A recombinant PrV HA n/a H5N1 168,169 Baculo HA n/a H1N1, H5N1, H6N8, H7N9, H9N2 [171][172][173][174][175][176][177][178] PIV-5 HA n/a H3N2, H5N1, H7N9 [180][181][182] NP n/a H5N1 182 HA n/a H7N9 181 HA/NP n/a H7N9 181 HA n/a H3N2 179 expressing HA from a swine A(H3N2) virus was tested in mice and induced protective immunity against infection with heterologous A (H3N2) virus. 131 An attenuated strain of equine herpesvirus (EHV-1), an alphaherpesvirus that infects horses, has an impressive safety record in horses and other mammalian species and therefore should be considered an attractive vaccine vector.…”

The Highly Conserved Proline at Position 438 in Pseudorabies Virus gH Is Important for Regulation of Membrane Fusion

“…pPrV-gH Ka was generated by reinsertion of the wild-type Kaplan gH (gH Ka ) together with a downstream-located kanamycin resistance gene (kan) for selection in Escherichia coli and was used here as the wild-type control. For comparison, a BAC clone (here designated pPrVBa) derived from PrV-Bartha (pPrV-Ba⌬gGG [26]), generated after deletion and reinsertion of the Bartha gH gene (gH Ba ), including the downstream kan, was used. The gH deletion mutants were grown in RK13-gHgL cells, while all the other recombinants were propagated on RK13 cells.…”

Strain Kaplan of Pseudorabies Virus Genome Sequenced by PacBio Single-Molecule Real-Time Sequencing Technology

“…PRV is a useful model organism for studies of the pathogenesis of herpesviruses. The genetically modified strains are powerful tracers for mapping neuronal circuits (2–6), are tools in gene and cancer therapy (7), and serve as viral vectors for gene delivery into mammalian neurons (3, 4) and cardiomyocytes (8); PRVs have also been employed as live vaccines against Aujeszky’s disease (9–11). Further, attenuated vaccine strains of PRV are valuable models for novel vaccine development against varicella-zoster virus (VZV) and herpes simplex virus 1 and 2 (HSV-1 and HSV-2, respectively) (12).…”