Plant-made E2 glycoprotein single-dose vaccine protects pigs against classical swine fever.

Classical Swine Fever Virus (CSFV) causes classical swine fever, a highly contagious hemorrhagic fever affecting both feral and domesticated pigs. Outbreaks of CSF in Europe, Asia, Africa and South America had significant adverse impacts on animal health, food security and the pig industry. The disease is generally contained by prevention of exposure through import restrictions (e.g. banning import of live pigs and pork products), localized vaccination programmes and culling of infected or at-risk animals, often at very high cost. Current CSFV-modified live virus vaccines are protective, but do not allow differentiation of infected from vaccinated animals (DIVA), a critical aspect of disease surveillance programmes. Alternatively, first-generation subunit vaccines using the viral protein E2 allow for use of DIVA diagnostic tests, but are slow to induce a protective response, provide limited prevention of vertical transmission and may fail to block viral shedding. CSFV E2 subunit vaccines from a baculovirus/insect cell system have been developed for several vaccination campaigns in Europe and Asia. However, this expression system is considered expensive for a veterinary vaccine and is not ideal for wide-spread deployment. To address the issues of scalability, cost of production and immunogenicity, we have employed an Agrobacterium-mediated transient expression platform in Nicotiana benthamiana and formulated the purified antigen in novel oil-in-water emulsion adjuvants. We report the manufacturing of adjuvanted, plant-made CSFV E2 subunit vaccine. The vaccine provided complete protection in challenged pigs, even after single-dose vaccination, which was accompanied by strong virus neutralization antibody responses.

A novel recombinant soluble splice variant of Met is a potent antagonist of the hepatocyte growth factor/scatter factor-Met pathway.

PURPOSE: The Met receptor tyrosine kinase and its ligand, hepatocyte growth factor/scatter factor (HGF/SF), are involved in a wide range of biological activities, including cell proliferation, motility, invasion, and angiogenesis. The HGF/SF-Met signaling pathway is frequently activated in a variety of cancers, and uncontrolled Met activation correlates with highly invasive tumors and poor prognosis. In this study, we investigated the inhibitory effect of a novel soluble splice variant of Met on the HGF/SF-Met pathway. EXPERIMENTAL DESIGN: Using our alternative splicing modeling platform LEADS, we have identified a novel splice variant of the Met receptor, which encodes a truncated soluble form of the receptor. This variant was produced as a recombinant Fc-fused protein named Cgen-241A and was tested in various cell-based assays representing different outcomes of the HGF/SF-Met pathway. RESULTS: Cgen-241A significantly inhibited HGF/SF-induced Met phosphorylation as well as cell proliferation and survival. In addition, Cgen-241A showed a profound inhibitory effect on cell scattering, invasion, and urokinase up-regulation. The inhibitory effects of Cgen-241A were shown in multiple human and nonhuman cell types, representing different modes of Met activation. Furthermore, Cgen-241A showed direct binding to HGF/SF. CONCLUSIONS: Taken together, our results indicate that Cgen-241A is a potent antagonist of the HGF/SF-Met pathway, underlining its potential as a therapeutic agent for the treatment of a wide variety of human malignancies that are dependent on this pathway.