Inhibition of melanoma growth by targeting of antigen to dendritic cells via an anti-DEC-205 single-chain fragment variable molecule.
OBJECTIVE
Our goal was to target melanoma antigens to the dendritic cell-specific receptor DEC-205. DEC-205 is an antigen receptor expressed on dendritic cells and has been shown to guide antigens to MHC class I and II compartments for processing and presentation to T cells.


METHODS
The melanoma tumor-associated antigen (TAA), gp100, was fused to the single-chain fragment variable (scFv) specific for DEC-205. The binding capacity of the scFv was tested on lymph node-isolated CD11c+ cells. Mixed lymphocyte reactions were carried out to show an increased proliferative capacity of gp100 antigen-specific CD4 and CD8 T cells. Furthermore the scFv-TAA was used in a therapeutic setting using two different melanoma mouse models.


RESULTS
C57Bl/6 mice were injected with scFv-DEC-205-gp100, monoclonal antibody anti-DEC-205, or PBS. Using fluorescence-activated cell sorting, we showed that lymph node CD11c+ dendritic cells stained positive for the binding of the scFv-mDEC-205-gp100 and the anti-DEC-205 monoclonal antibody, whereas the PBS-injected animals were negative. In mixed lymphocyte reactions, bone marrow-derived dendritic cells pulsed with scFv-mDEC-205-gp100 significantly increased proliferation of gp100-specific CD8+ and CD4+ T cells beyond gp100 peptide-pulsed or nonpulsed bone marrow-derived dendritic cells. Finally, in B16/F10 and RET models, a concentration-dependent suppression of tumor growth using scFv-mDEC-205-gp100 (66% reduction of tumor volume), in comparison with gp100 peptide vaccination, was observed.


CONCLUSIONS
Our results indicate that the scFv-mDEC-205-gp100 targets TAA to dendritic cells in vivo for presentation on both MHC class I and II molecules. In vivo, this leads to an improved immune response and a decrease in tumor growth rate.
Johnson
Theron S
TS
Department of Dermatology, University Hospital Heidelberg, Heidelberg, Germany. theron.johnson@med.uni-heidelberg.de
Mahnke
Karsten
K
Storn
Volker
V
Schönfeld
Kurt
K
Ring
Sabine
S
Nettelbeck
Dirk M
DM
Haisma
Hidde J
HJ
Le Gall
Fabrice
F
Kontermann
Roland E
RE
Enk
Alexander H
AH
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015703:Antigens, CD / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology*; D007128:Immunoglobulin Fragments / Q000627:therapeutic use*; D037181:Lectins, C-Type / Q000276:immunology*; D008546:Melanoma, Experimental / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens; D011956:Receptors, Cell Surface / Q000276:immunology*; D058951:gp100 Melanoma Antigen
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; C093569:DEC-205 receptor; D007128:Immunoglobulin Fragments; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D015778:Minor Histocompatibility Antigens; C548642:Pmel protein, mouse; D011956:Receptors, Cell Surface; D058951:gp100 Melanoma Antigen; C055966:immunoglobulin Fv