Enhanced generation of cytotoxic T lymphocytes by increased cytosolic delivery of MHC class I epitope fused to mouse heat shock protein 70 via polyhistidine conjugation

Malaria DNA vaccine gp96NTD-CSP elicits both CSP-specific antibody and CD8+ T cell response

“…Heat-shock protein (HSP), an intracellular molecular chaperone, is regarded as a danger signal when it is released from cells. Gp96/grp94, an endoplasmic reticulum retention heat-shock protein, could not only activate dendritic cells though TLR (Toll-like receptor) 2 and 4 (Asea et al 2002;Vabulas et al 2002) but also facilitate the binding polypeptides to be presented to MHC class I molecules and active peptide-specific CD8 + T cells (Takemoto et al 2010;Takemoto et al 2009). Therefore, we hypothesized that gp96 might induce both CSP-specific antibody and CD8 + T cell response when fused with the full-length CSP.…”

Enhanced Generation of Cytotoxic T Lymphocytes by Heat Shock Protein 70 Fusion Proteins Harboring Both CD8+ T Cell and CD4+ T Cell Epitopes

“…Figure A shows the schematic structures of the designed constructs. A typical MHC class I epitope of OVA, SIINFEKL (OVA 257−264 , pepI) and TEWTS sequence, which has been reported to facilitate the degradation of the SIINFEKL peptide in the proteasomes, was fused to the C-terminus of the Hsp70 because the conjugation of pepI to C-terminus was a more efficient design to induce CTL responses in comparison with the N-terminus conjugation. , Therefore, we did not examine N-terminus conjugation of pepI in this study. For preliminary evaluations to decide the appropriate conjugation of CD4 + T cell epitope with Hsp70, a typical CD4 + T cell epitope of OVA, ISQAVHAAHAEINEAGR (OVA 323−339 , pepII) was fused to the N or C-terminal of Hsp70.…”

“…In our series of studies, we have developed a variety of Hsp70-based antigen delivery systems. With regard to our previous antigen delivery system, we have focused solely on the CD8 + T cell epitope and developed a protein vaccine of the epitope fused to polyhistidine-Hsp70 fusion protein and a DNA vaccine encoding the gene of the protein vaccine . The CD4 + T cell epitope could be used in our antigen delivery systems.…”

“…In the present study, we have shown that an OVA class II antigenic peptide (OVA 323−339 ; ISQAVHAAHAEINEAGR) fused to Hsp70, a novel design for Hsp70 based tumor vaccines, was effectively presented on primary cultured mouse MΦ cells compared with OVA, and would be taken up by MΦ cells probably via mannose receptors (Figure ). As shown in pepI fusion proteins, Hsp70 could also be a useful carrier for pepII via CD91 or LOX-1 receptors in MHC class II antigen presentation. Regarding the site for conjugation of pepII, the N-terminus of Hsp70 was slightly but significantly better than the C-terminus in terms of the activity of MHC class II antigen presentation.…”

“…We have also succeeded in designing a delivery approach to control the intracellular pharmacokinetics of Hsp70. We have developed a fusion protein, CD8 + T cell epitope fused to Hsp70-polyhistidine protein, which can enhance cytosolic delivery and subsequently improve the MHC class I antigen presentation in DCs and increase the CTL activity . This approach has been applied to a DNA vaccine, plasmid DNA (pDNA) encoding polyhistidine-Hsp70-CD8 + T cell epitope fusion protein gene, which showed a higher CTL activity than the corresponding protein vaccine .…”