Single-step antigen loading and activation of dendritic cells by mRNA electroporation for the purpose of therapeutic vaccination in melanoma patients.
OBJECTIVE
A critical factor determining the effectiveness of currently used dendritic cell (DC)-based vaccines is the DC activation or maturation status. We have recently shown that the T-cell stimulatory capacity of DCs pulsed with tumor-antigen-derived peptides can be considerably increased by activating the DCs through electroporation with mRNA encoding CD40 ligand, CD70, and a constitutively active Toll-like receptor 4 (TriMix DCs). Here, we investigate whether TriMix DCs can be coelectroporated with whole tumor-antigen-encoding mRNA.


METHODS
The T-cell stimulatory capacity of TriMix DCs pulsed with the immunodominant MelanA-A2 peptide and that of TriMix DCs coelectroporated with MelanA mRNA were compared in vitro. TriMix DCs were also coelectroporated with mRNA encoding Mage-A3, Mage-C2, tyrosinase, or gp100. The capacity of these DCs to stimulate tumor-antigen-specific T cells in melanoma patients was investigated both in vitro before vaccination and after DC vaccination.


RESULTS
Like peptide-pulsed TriMix DCs, TriMix DCs coelectroporated with MelanA mRNA are very potent in inducing MelanA-specific CD8(+) T cells in vitro. These T cells have an activated phenotype, show cytolytic capacity, and produce inflammatory cytokines in response to specific stimulation. TriMix DCs coelectroporated with tyrosinase are able to stimulate tyrosinase-specific CD8(+) T cells in vitro from the blood of nonvaccinated melanoma patients. Furthermore, TriMix DCs coelectroporated with Mage-A3, Mage-C2, or tyrosinase are able to induce antigen-specific CD8(+) T cells through therapeutic DC vaccination.


CONCLUSIONS
TriMix DCs coelectroporated with whole tumor-antigen mRNA stimulate antigen-specific T cells in vitro and induce antigen-specific T-cell responses in melanoma patients through vaccination. Therefore, they represent a promising new approach for antitumor immunotherapy.
Laboratory of Molecular and Cellular Therapy, Department of Physiology-Immunology, Medical School of the Vrije Universiteit Brussel, Brussels, Belgium. abonehil@vub.ac.be
Aude
A
Bonehill
An M T
AM
Van Nuffel
Jurgen
J
Corthals
Sandra
S
Tuyaerts
Carlo
C
Heirman
Violaine
V
François
Didier
D
Colau
Pierre
P
van der Bruggen
Bart
B
Neyns
Kris
K
Thielemans
D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D053282:CD27 Ligand / Q000235:genetics / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018274:Electroporation / Q000379:methods*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D052118:Lysosomal-Associated Membrane Protein 1 / Q000378:metabolism; D058965:MART-1 Antigen; D008297:Male; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000276:immunology; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9 / Q000378:metabolism; D014611:Vaccination / Q000379:methods; D058951:gp100 Melanoma Antigen
D000951:Antigens, Neoplasm; D053282:CD27 Ligand; C505771:CD70 protein, human; D019496:Cancer Vaccines; D016207:Cytokines; D052118:Lysosomal-Associated Membrane Protein 1; C072013:MAGEA3 protein, human; C405429:MAGEC2 protein, human; D058965:MART-1 Antigen; C548667:MLANA protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D012333:RNA, Messenger; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9; D058951:gp100 Melanoma Antigen; D014442:Monophenol Monooxygenase