Publications

Picornaviruses replicate their genomes in association with cellular membranes. While enteroviruses are believed to utilize membranes of the early secretory pathway, the origin of the membranes used by foot-and-mouth disease virus (FMDV) for replication are unknown. Secretory-vesicle traffic through the early secretory pathway is mediated by the sequential acquisition of two distinct membrane coat complexes, COPII and COPI, and requires the coordinated actions of Sar1, Arf1 and Rab proteins. Sar1 is essential for generating COPII vesicles at endoplasmic reticulum (ER) exit sites (ERESs), while Arf1 and Rab1 are required for subsequent vesicle transport by COPI vesicles. In the present study, we have provided evidence that FMDV requires pre-Golgi membranes of the early secretory pathway for infection. Small interfering RNA depletion of Sar1 or expression of a dominant-negative (DN) mutant of Sar1a inhibited FMDV infection. In contrast, a dominant-active mutant of Sar1a, which allowed COPII vesicle formation but inhibited the secretory pathway by stabilizing COPII coats, caused major disruption to the ER-Golgi intermediate compartment (ERGIC) but did not inhibit infection. Treatment of cells with brefeldin A, or expression of DN mutants of Arf1 and Rab1a, disrupted the Golgi and enhanced FMDV infection. These results show that reagents that block the early secretory pathway at ERESs have an inhibitory effect on FMDV infection, while reagents that block the early secretory pathway immediately after ER exit but before the ERGIC and Golgi make infection more favourable. Together, these observations argue for a role for Sar1 in FMDV infection and that initial virus replication takes place on membranes that are formed at ERESs.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases of swine worldwide. Since its first emergence in 1987 the PARS virus (PRRSV) has become particularly divergent with highly pathogenic strains appearing in both Europe and Asia. However, the underlying mechanisms of PRRSV pathogenesis are still unclear. This study sets out to determine the differences in pathogenesis between subtype 1 and 3 strains of European PRRSV (PRRSV-I), and compare the immune responses mounted against these strains. Piglets were infected with 3 strains of PRRSV-I: Lelystad virus, 215-06 a British field strain and SU1-bel from Belarus. Post-mortem examinations were performed at 3 and 7 days post-infection (dpi), and half of the remaining animals in each group were inoculated with an Aujeszky's disease (ADV) vaccine to investigate possible immune suppression resulting from PRRSV infection. The subtype 3 SU1-bel strain displayed greater clinical signs and lung gross pathology scores compared with the subtype 1 strains. This difference did not appear to be caused by higher virus replication, as viraemia and viral load in broncho-alveolar lavage fluid (BALF) were lower in the SU1 -bel group. Infection with SU1 -bel induced an enhanced adaptive immune response with greater interferon (IFN)-gamma responses and an earlier PRRSV-specific antibody response. Infection with PRRSV did not affect the response to vaccination against ADV. Our results indicate that the increased clinical and pathological effect of the SU1 -bel strain is more likely to be caused by an enhanced inflammatory immune response rather than higher levels of virus replication.

Licensed seasonal influenza vaccines induce antibody (Ab) responses against influenza hemagglutinin (HA) that are limited in their ability to protect against different strains of influenza. Cytotoxic T lymphocytes recognizing the conserved internal nucleoprotein (NP) and matrix protein (M1) are capable of mediating a cross-subtype immune response against influenza. Modified vaccinia Ankara (MVA) virus encoding NP and M1 (MVA-NP+M1) is designed to boost preexisting T-cell responses in adults in order to elicit a cross-protective immune response. We examined the coadministration of HA protein formulations and candidate MVA-NP+M1 influenza vaccines in murine, avian, and swine models. Ab responses postimmunization were measured by ELISA and pseudotype neutralization assays. Here, we demonstrate that MVA-NP+M1 can act as an adjuvant enhancing Ab responses to HA while simultaneously inducing potent T-cell responses to conserved internal Ags. We show that this regimen leads to the induction of cytophilic Ab isotypes that are capable of inhibiting hemagglutination and in the context of H5 exhibit cross-clade neutralization. The simultaneous induction of T cells and Ab responses has the potential to improve seasonal vaccine performance and could be employed in pandemic situations.

The purpose of this book is to provide a timely and comprehensive review on all the mononegaviruses of veterinary importance. The book is divided into two sections. Section I deals with 13 mononegaviruses (Bornaviruses, Avian Paramyxoviruses serotypes 1 to 10, Hendra and Nipah viruses, Canine distemper virus, Peste des petits ruminants virus, Rinderpest virus, Bovine parainfluenza virus, Swine parainfluenza virus, Porcine rubulavirus (PoRV -LPMV), Bovine respiratory syncytial virus, Avian metapneumoviruses, Bovine ephemeral fever virus and Rabies virus) of livestock, horses, dogs and cats; whereas Section II comprises of 9 other mononegaviruses (Ebolavirus, Marburgvirus, Phocine distemper virus, Morbilliviruses, Sendai virus, pneumonia virus, Infectious hematopoietic necrosis virus, Viral haemorrhagic septicaemia virus and Snakehead rhabdovirus) of rodents, primates, fish and sea mammals. A full chapter is dedicated to each virus which provides up-to-date literature on historical distribution, genome structure, viral proteins, reverse genetics, immunity, viral pathogenesis, clinical and molecular diagnosis and future challenges. Every chapter is written by renowned scientists who have made seminal contributions in their respective mononegavirus fields of expertise. Each chapter is attempted to make as stand-alone document, making it a valuable reference source for virologists, field veterinarians, infection and molecular biologists, immunologists, scientists in related fields and veterinary school libraries.