Suppression of choroidal neovascularization by dendritic cell vaccination targeting VEGFR2.
OBJECTIVE
To investigate whether the induction of cellular immunity against vascular endothelial growth factor receptor (VEGFR) 2 inhibits the development of choroidal neovascularization (CNV).


METHODS
H-2Db-restricted peptide corresponding to amino acids 400 to 408 of VEGFR2 was used as an epitope peptide. Dendritic cells (DCs) were harvested from bone marrow progenitors of C57BL/6 mice. Six-week-old C57BL/6 mice received subcutaneous injections of the epitope peptide-pulsed mature DCs three times at 6-day intervals. After the third immunization, laser photocoagulation was performed to induce CNV. One week after photocoagulation, mice were killed to harvest the choroid and splenocytes. CNV volume was evaluated by volumetric measurements. To confirm the specific immunogenicity of the epitope peptides in C57BL/6 mice, CD8 T cells isolated from harvested splenocytes were restimulated to measure interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production through enzyme-linked immunospot assay and ELISA. To determine the T-cell subset responsible for the immunotherapy, mice were intraperitoneally injected with an anti-CD4 or anti-CD8 depletion antibody.


RESULTS
CNV volume was significantly lower in mice immunized with the VEGFR2 epitope peptide than in those not immunized or immunized with a control peptide gp70. Cytokine assays showed the peptide-specific production of IFN-gamma and TNF-alpha from the CD8 T cells in a dose-dependent manner. In vivo depletion of CD8, but not CD4, T cells significantly reversed the suppressive effect of the VEGFR2 peptide-pulsed DC vaccination on CNV to the level observed in nonimmunized or gp70-immunized animals.


CONCLUSIONS
These results indicate that the VEGFR2 peptide-specific induction of cellular immunity inhibits CNV through the cytotoxicity of CD8 T cells. Results of the present study suggested the possibility of DC vaccination targeting VEGFR2 as a novel therapeutic strategy for CNV.
Mochimaru
Hiroshi
H
Laboratory of Retinal Cell Biology, Keio University School of Medicine, Shinanomachi, Tokyo, Japan.
Nagai
Norihiro
N
Hasegawa
Go
G
Kudo-Saito
Chie
C
Yaguchi
Tomonori
T
Usui
Yoshihiko
Y
Kurihara
Toshihide
T
Koto
Takashi
T
Satofuka
Shingo
S
Shinoda
Hajime
H
Ozawa
Yoko
Y
Tsubota
Kazuo
K
Kawakami
Yutaka
Y
Ishida
Susumu
S
D000818:Animals; D015496:CD4-Positive T-Lymphocytes; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D020256:Choroidal Neovascularization / Q000378:metabolism / Q000517:prevention & control*; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000378:metabolism; D008212:Lymphocyte Depletion; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009842:Oligopeptides / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014611:Vaccination; D022223:Vaccines, Subunit / Q000008:administration & dosage; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000276:immunology*
D000939:Epitopes; D009842:Oligopeptides; D014409:Tumor Necrosis Factor-alpha; D022223:Vaccines, Subunit; D007371:Interferon-gamma; D040301:Vascular Endothelial Growth Factor Receptor-2