Yeast-surface expressed BVDV E2 protein induces a Th1/Th2 response in naïve T cells

Robert Patterson,Jessica Nerren,Michael Kogut,Pinar Court,Bernardo Villarreal-Ramos,Hans-Martin Seyfert,Paul Dalby,Dirk Werling

doi:10.1016/j.dci.2011.10.009

Robert Patterson, Jessica Nerren + Show 6 more

Open Access

https://doi.org/10.1016/j.dci.2011.10.009

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Abstract

Yeast species such as Saccharomyces cerevisiae are known to be 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 S. cerevisiae. After successful expression, components of the innate and adaptive immune response induced by the recombinant S. cerevisiaein 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 no stimulate production of reactive oxygen species (ROS) 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 counter-part. Additionally, heat-inactivation of recombinant S. cerevisiae induced less INFγ 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 cell in order to elicit cell-mediated immunity even in naïve animals.

Highlights

Recognition of invading antigen by the immune system is key for tailoring an appropriate immune response in order to quell infection
Dectin-1 collaborates with TLR2, as well as acting independently, to initiate a wide range of microbial responses, especially against fungal pathogens
We used bovine MØ stimulated with the S. cerevisiae displaying the envelope protein 2 (E2) protein at the surface and S. cerevisiae with no expression of the E2 surface protein and measured their capacity to produce reactive oxygen species (ROS), CXCL8 and their capacity to induce proliferation of CD4+ T-cells

Summary

Introduction

Recognition of invading antigen by the immune system is key for tailoring an appropriate immune response in order to quell infection. This recognition is facilitated through pattern recognition receptors (PRRs), which recognise conserved structures on invading microbes termed pathogen associated molecular patterns (PAMPs). Ligation of these PAMPs to their corresponding PRRs induces a very specific immune response. Of the many PRRs known, the toll like receptors (TLRs) are the best characterised and most extensively studied.

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