PurposePersonalized peptide-based cancer vaccines will be composed of multiple patient specific synthetic long peptides (SLPs) which may have various physicochemical properties. To formulate such... Show morePurposePersonalized peptide-based cancer vaccines will be composed of multiple patient specific synthetic long peptides (SLPs) which may have various physicochemical properties. To formulate such SLPs, a flexible vaccine delivery system is required. We studied whether cationic liposomes are suitable for this purpose.MethodsFifteen SIINFEKL T cell epitope-containing SLPs, widely differing in hydrophobicity and isoelectric point, were separately loaded in cationic liposomes via the dehydration-rehydration method. Particle size and polydispersity index (PDI) were measured via dynamic light scattering (DLS), and zeta potential with laser Doppler electrophoresis. Peptide loading was fluorescently determined and the immunogenicity of the formulated peptides was assessed in co-cultures of dendritic cells (DCs) and CD8(+) T-cells in vitro.ResultsAll SLPs were loaded in cationic liposomes by using three different loading method variants, depending on the SLP characteristics. The fifteen liposomal formulations had a comparable size (< 200nm), PDI (< 0.3) and zeta potential (22-30mV). Cationic liposomes efficiently delivered the SLPs to DCs that subsequently activated SIINFEKL-specific CD8(+) T-cells, indicating improved immunological activity of the SLPs.ConclusionCationic liposomes can accommodate a wide range of different SLPs and are therefore a potential delivery platform for personalized cancer vaccines. Show less
Heuts, J.M.M.; Varypataki, E.M.; Maaden, K. van der; Romeijn, S.G.; Drijfhout, J.W.; Scheltinga, A.T. van; ... ; Jiskoot, W. 2018
PurposePersonalized peptide-based cancer vaccines will be composed of multiple patient specific synthetic long peptides (SLPs) which may have various physicochemical properties. To formulate such... Show morePurposePersonalized peptide-based cancer vaccines will be composed of multiple patient specific synthetic long peptides (SLPs) which may have various physicochemical properties. To formulate such SLPs, a flexible vaccine delivery system is required. We studied whether cationic liposomes are suitable for this purpose.MethodsFifteen SIINFEKL T cell epitope-containing SLPs, widely differing in hydrophobicity and isoelectric point, were separately loaded in cationic liposomes via the dehydration-rehydration method. Particle size and polydispersity index (PDI) were measured via dynamic light scattering (DLS), and zeta potential with laser Doppler electrophoresis. Peptide loading was fluorescently determined and the immunogenicity of the formulated peptides was assessed in co-cultures of dendritic cells (DCs) and CD8(+) T-cells in vitro.ResultsAll SLPs were loaded in cationic liposomes by using three different loading method variants, depending on the SLP characteristics. The fifteen liposomal formulations had a comparable size (< 200nm), PDI (< 0.3) and zeta potential (22-30mV). Cationic liposomes efficiently delivered the SLPs to DCs that subsequently activated SIINFEKL-specific CD8(+) T-cells, indicating improved immunological activity of the SLPs.ConclusionCationic liposomes can accommodate a wide range of different SLPs and are therefore a potential delivery platform for personalized cancer vaccines. Show less
Varypataki, E.M.; Benne, N.; Bouwstra, J.; Jiskoot, W.; Ossendorp, F. 2017
Synthetic long peptides (SLP) derived from cancer-associated antigens hold great promise as well-defined antigens for cancer immunotherapy. Clinical studies showed that SLP vaccines have... Show more Synthetic long peptides (SLP) derived from cancer-associated antigens hold great promise as well-defined antigens for cancer immunotherapy. Clinical studies showed that SLP vaccines have functional potency when applied to pre-malignant stage patients, but need to be improved for use as a therapeutic intervention against tumours. So far, SLPs have been administered in Montanide ISA-51, a water-in-oil formulation with reported important drawbacks and induced local side effects. Therefore, there is an urgent need for replacement of Montanide by more potent and safe alternatives. In this thesis, the concept of cationic liposome-based formulations was introduced, as the backbone for improved delivery of SLPs for cancer therapeutic vaccination. The developed formulation’s ability to induce efficient immune responses able to control tumour outgrowth in aggressive independent tumour models, makes cationic liposomes a very promising platform for SLP-based cancer immunotherapy. Their flexibility regarding the properties of loaded SLPs, their relative inexpensive production and the possibility to administer them via different delivery routes are all in favour for liposomal SLP-based cancer immunotherapy to become reality soon. Show less
Nanoparticulate formulations for synthetic long peptide (SLP)-cancer vaccines as alternative to clinically used Montanide ISA 51- and squalene-based emulsions are investigated in this study. SLPs... Show moreNanoparticulate formulations for synthetic long peptide (SLP)-cancer vaccines as alternative to clinically used Montanide ISA 51- and squalene-based emulsions are investigated in this study. SLPs were loaded into TLR ligand-adjuvanted cationic liposomes and PLGA nanoparticles (NPs) to potentially induce cell-mediated immune responses. The liposomal and PLGA NP formulations were successfully loaded with up to four different compounds and were able to enhance antigen uptake by dendritic cells (DCs) and subsequent activation of T cells in vitro. Subcutaneous vaccination of mice with the different formulations showed that the SLP-loaded cationic liposomes were the most efficient for the induction of functional antigen-T cells in vivo, followed by PLGA NPs which were as potent as or even more than the Montanide and squalene emulsions. Moreover, after transfer of antigen-specific target cells in immunized mice, liposomes induced the highest in vivo killing capacity. These findings, considering also the inadequate safety profile of the currently clinically used adjuvant Montanide ISA-51, make these two particulate, biodegradable delivery systems promising candidates as delivery platforms for SLP-based immunotherapy of cancer. Show less
Varypataki, E.M.; Maaden, K. van der; Bouwstra, J.; Ossendorp, F.; Jiskoot, W. 2015
