Original article

Hsp70 enhances presentation of FMDV antigen to bovine CD4⁺ T cells in vitro

¹ Institute for Animal Health, Pirbright, Woking, Surrey GU24 0NF, United Kingdom
² King’s College London, Dental Institute, Guy’s Hospital, London SE1 9RT, United Kingdom
³ Institute for Animal Health, Compton, Newbury, Berkshire RG20 7NN, United Kingdom

^* Corresponding author: bryan.charleston@bbsrc.ac.uk

Received: 18 August 2009
Accepted: 29 January 2010

Abstract

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious acute vesicular disease affecting cloven-hoofed animals, including cattle, sheep and pigs. The current vaccine induces a rapid humoral response, but the duration of the protective antibody response is variable, possibly associated with a variable specific CD4⁺ T cell response. We investigated the use of heat shock protein 70 (Hsp70) as a molecular chaperone to target viral antigen to the Major Histocompatibility Complex (MHC) class II pathway of antigen presenting cells and generate enhanced MHC II-restricted CD4⁺ T cell responses in cattle. Monocytes and CD4⁺ T cells from FMDV vaccinated cattle were stimulated in vitro with complexes of Hsp70 and FMDV peptide, or peptide alone. Hsp70 was found to consistently improve the presentation of a 25-mer FMDV peptide to CD4⁺ T cells, as measured by T cell proliferation. Complex formation was required for the enhanced effects and Hsp70 alone did not stimulate proliferation. This study provides further evidence that Hsp70:peptide complexes can enhance antigen-specific CD4⁺ T cell responses in vitro for an important pathogen of livestock.