|Kogut, Michael - Mike|
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/22/2011
Publication Date: 10/31/2011
Publication URL: http://handle.nal.usda.gov/10113/58136
Citation: Patterson, R., Nerren, J., Kogut, M.H., Court, P., Villareal-Ramos, B., Seyfert, H., Dalby, P., Werling, D. 2011. Yeast-surface expressed BVDV E2 protein induces a Th1/Th2 response in naïve T cells. Developmental and Comparative Immunology. 37:107-114. Interpretive Summary: Baby cows get sick with a deadly virus called Bovine viral diarrhoea virus. There are many vaccines available to protect these baby animals with different levels of success and duration of protection. However, there is a risk that many of the best vaccines have been chemically treated so they do not cause disease, but they are live viruses. Unfortunately, many of these vaccine viruses can change back to a form that can cause disease and thus become dangerous to the baby cows. In the current study, we took the structures from the virus that can protect the cows and put them into another microbe called a yeast. The yeast does not cause disease in cows. We show that by giving the baby cows this yeast with the virus parts that we could protect the calves from the virus infection with no worries about the virus changing back to a disease-causing bug. This work is important because the cattle industry now can protect the baby cows from this deadly virus.
Technical Abstract: Yeast species such as Saccharomyces cerevisiae (S. cerevisiae) are well documented as being potent activators of the immune system. S. cerevisiae activates the innate immune system by engaging pattern recognition receptors such as toll like receptor 2 (TLR2) and dectin-1. In the current project, we express the immunogenic envelope protein E2 of bovine viral diarrhoea virus (BVDV) on the surface of the yeast S. cerevisiae. After successful expression, components of the innate and adaptive immune response induced by the recombinant S. cerevisiae in vitro were analysed to determine if expression in yeast enhances the immunogenicity of the viral protein. Recombinant S. cerevisiae stimulated production of the chemokine CXCL-8 in primary bovine macrophages but did not stimulate production of reactive oxygen species in the same cells. Additionally, bovine macrophages primed with S. cerevisiae expressing viral envelope proteins had a greater capacity for stimulating proliferation of CD4+ T-cells from BVDV-free animals compared to macrophages primed with envelope protein alone or S. cerevisiae without envelope protein expression. Heat inactivation of recombinant S. cerevisiae increased ROS production and capacity to stimulate CD4+ T-cells in macrophages but did not alter CXCL-8 release compared to the live counterpart. Additionally, heat-inactivation of recombinant S. cerevisiae induced less INF' and IL-4 but equal amounts of IL-10 compared to live yeast T-cell cultures. Our studies demonstrate a use for S. cerevisiae as a vehicle for transporting BVDV vaccine antigen to antigen-presenting cells in order to elicit cell-mediated immunity even in naïve animals.