C-terminal heat shock protein 70 of Mycobacterium tuberculosis as a molecular adjuvant for DNA vaccination with the porcine circovirus type 2 ORF2 (capsid) gene in mice

Mycobacterium tuberculosis heat shock protein 70 (HSP70) and the peptide binding C-terminal portion of HSP70 (amino acids 359-610; HSP70c) exert an adjuvant effect when used in vaccines. To enhance the immunogenicity of a DNA vaccine against porcine circovirus type 2 (PCV2), recombinant plasmids encoding the PCV2 ORF2 (capsid) gene fused to full length hsp70 (pCA-TCH) or truncated C-terminal hsp70c (pCA-TCHc) were constructed. Immunisation of mice with pCA-TCHc induced higher serum immunoglobulin G antibody levels, stronger T helper 1 immune responses and lower PCV2 viral titres following challenge than immunisation with pCA-TCH or Cap plasmids only.