Suppression of choroidal neovascularization by vaccination with epitope peptide derived from human VEGF receptor 2 in an animal model.
OBJECTIVE
It has been shown that vaccination with peptides derived from human vascular endothelial growth factor receptor 2 (VEGFR2) induces cytotoxic T lymphocytes (CTLs) with potent cytotoxicity against endothelial cells expressing VEGFR2 in a A2/Kb transgenic mice system expressing human HLA-A*0201. The present study examined the efficacy of this immunotherapy against age-related macular degeneration (AMD) using a choroidal neovascularization (CNV) model.


METHODS
Seven- to 10-week-old A2/Kb transgenic mice expressing human HLA-A*0201 were used. The mice were divided into three groups of 15 animals each: phosphate-buffered saline (PBS) treatment (control); immunity adjuvant (incomplete Freund adjuvant [IFA]); and antigen peptide of human VEGFR 2 and IFA (peptide vaccination group). Immunization was given on days 0 and 11. On day 20, six CNVs were induced in both eyes of each animal using a semiconductor laser set to 75 mum, 200 mW, and 0.05 seconds. Leakage from the CNV was measured by fluorescein angiography 7 days after laser treatment. CNV volume was measured using a choroidal flatmount after perfusing the mice with fluorescein conjugate lectin.


RESULTS
There were no significant differences in the leakage or the area of CNV in the IFA-treated group compared with controls. In contrast, the fluorescent leakage index in the peptide vaccination group was reduced to 80% and the CNV area to 18% compared with the control group (P < 0.0001 and P < 0.05, respectively).


CONCLUSIONS
This model provides a rationale for immunotherapy using the epitope peptides derived from VEGFR2 for the treatment of CNV.
Takahashi
Hidenori
H
Department of Ophthalmology, The Institute of Medical Science, School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
Ishizaki
Hidenobu
H
Tahara
Hideaki
H
Tamaki
Yasuhiro
Y
Yanagi
Yasuo
Y
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D020256:Choroidal Neovascularization / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D004195:Disease Models, Animal; D000939:Epitopes / Q000276:immunology*; D005451:Fluorescein Angiography; D007114:Immunization; D007124:Immunoenzyme Techniques; D007167:Immunotherapy; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000276:immunology*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014611:Vaccination; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000939:Epitopes; D010446:Peptide Fragments; D012333:RNA, Messenger; D040301:Vascular Endothelial Growth Factor Receptor-2