Introduction of Soluble Proteins into the MHC Class I Pathway by Conjugation to an HIV tat Peptide
ABSTRACT Protection against most intracellular pathogens requires T cells that recognize pathogen-derived peptides in association with MHC class I molecules on the surface of infected cells. However, because exogenous proteins do not ordinarily enter the cytosol and access the MHC class I-processing pathway, protein-based vaccines that induce class I-restricted CTL responses have proved difficult to design. We have addressed this problem by conjugating proteins, such as OVA, to a short cationic peptide derived from HIV-1 tat (residues 49-57). When APC were exposed in vitro to such protein conjugates, they processed and presented the peptides in association with MHC class I molecules and stimulated CD8+ Ag-specific T cells. Moreover, Ag-specific CTLs were generated in vivo by immunizing mice with histocompatible dendritic cells that had been exposed to protein-tat conjugates.
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ABSTRACT: To investigate the role of enhanced antigen presentation in dendritic cell (DC)-based immunotherapy. Here, we describe the development of a cell-penetrating mucin 1 (MUC1) antigen and its immunotherapeutic potential against tumors. After animal groups received two immunizations of MUC1-MPA(11)P-pulsed DCs, we observed a marked tumor regression compared with the mice treated with DCs alone or DCs pulsed with MUC1 peptide. We confirmed the migration and homing of DCs in the popliteal lymph node using magnetic resonance imaging during the study. In summary, enhanced antigen uptake using an MPA(11)P delivery molecule improves cell therapy.Translational oncology 02/2011; 4(1):1-8. DOI:10.1593/tlo.10166 · 3.40 Impact Factor
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ABSTRACT: The ultimate success of cancer vaccination is dependent upon the generation of tumor-specific CTLs. In this study, we designed and evaluated a novel fusion protein comprising a cell penetrating and immunostimulatory peptide corresponding to residues 32-51 of the Limulus polyphemus protein (LALF(32-51)) linked to human papillomavirus (HPV) 16 E7 antigen (LALF(32-51)-E7). We demonstrated that LALF(32-51) penetrates the cell membrane and delivers E7 into cells. In a preclinical model of HPV16-induced cervical carcinoma we showed that vaccination with adjuvant-free LALF(32-51)-E7 fusion protein significantly improves the presentation of E7-derived peptides to T-cells in vitro and induces suppression of tumor growth.Vaccine 01/2011; 29(5):920-30. DOI:10.1016/j.vaccine.2010.11.083 · 3.49 Impact Factor
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ABSTRACT: Survivin (SVV), a member of the inhibitors of apoptosis, has been considered as an ideal tumor-associated antigen due to its broad expression pattern in many types of human malignancies. Here, SVV-specific immune responses were evaluated with dendritic cells (DCs) loaded with a recombinant tatPTD fused SVV (tatSVV) protein both in vitro and in vivo system. The tatPTD fusion allowed for highly efficient and reproducible protein delivery into the DCs even in the presence of a phagocytosis inhibitor. The level of SVV-specific cytotoxic T-cell response appeared to be significantly higher for the T-cell line that was primed with the tatSVV-pulsed DCs, as compared to the T-cell line produced with naked (n)-SVV-pulsed DCs in vitro. Mice that received a xenogeneic tatSVV-pulsed DC vaccine developed a higher immune response than mice vaccinated with the nSVV-pulsed DCs and exhibited prolonged mean survival rate, though mice injected with the DCs alone or the nSVV-pulsed DC also showed anti-tumor effects in the subcutaneous GL26 glioma model. These results suggest that vaccination with DCs pulsed with tatSVV is an effective way for the SVV-targeting cancer vaccine to induce an effective anti-tumor responses.Cancer Letters 01/2008; 258(2):189-98. DOI:10.1016/j.canlet.2007.08.023 · 5.02 Impact Factor