Inhibitory effect of an antibody to cryptic collagen type IV epitopes on choroidal neovascularization.
OBJECTIVE
The wet form of age-related macular degeneration (AMD) occurs as a consequence of abnormal blood vessel growth from the choroid into the retina. Pathological angiogenesis during tumor growth and ocular disease has been associated with specific exposure of cryptic extracellular matrix epitopes. We investigated the presence of cryptic collagen IV epitopes in a murine model of choroidal neovascularization (CNV), and tested the effect on blood vessel growth of H8, a humanized antibody directed against a cryptic collagen type IV epitope.


METHODS
To induce experimental CNV in adult C57BL/6 mice, Bruch's membrane was ruptured using a diode laser. Subsequently, mice were treated with daily intraperitoneal (i.p.) injections of either H8 (10 mg/kg or 30 mg/kg) or an isotype-matched antibody control. Two weeks postinjection, choroidal flat mounts were immunostained with the blood vessel marker platelet/endothelial cell adhesion molecule-1 (PECAM-1) and H8. CNV was visualized using fluorescence microscopy and the CNV lesion area measured using Open Lab software.


RESULTS
Collagen type IV and the cryptic epitope were observed at the site of laser-induced lesions. Staining with H8 was first observed three days post injury, two days after MMP2 expression in CNV lesions, becoming most intense five days following laser injury and extending beyond the area of neovascularization. At 14 days post injury, H8 staining was reduced in intensity, colocalized with the area of CNV, and was nearly absent from the underlying choroidal vessels. In addition, mice treated with H8 had a significant dose-dependent decrease in the area of CNV as compared to isotype-matched antibody controls.


CONCLUSIONS
Results suggest that exposure of cryptic collagen type IV epitopes is associated with the incidence of CNV and that the humanized antibody H8 may provide a new treatment for CNV.
Jo
Nobuo
N
OSI Eyetech, Eyetech Research Center, Lexington, MA 02421, USA.
Ju
Meihua
M
Nishijima
Kazuaki
K
Robinson
Gregory S
GS
Adamis
Anthony P
AP
Shima
David T
DT
Mailhos
Carolina
C
D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology*; D020256:Choroidal Neovascularization / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D024141:Collagen Type IV / Q000276:immunology*; D000939:Epitopes / Q000276:immunology* / Q000378:metabolism; D005109:Extracellular Matrix / Q000276:immunology; D005123:Eye / Q000187:drug effects / Q000378:metabolism; D005131:Eye Injuries / Q000276:immunology / Q000378:metabolism; D006358:Hot Temperature; D007150:Immunohistochemistry / Q000379:methods; D007834:Lasers; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011489:Protein Denaturation; D011832:Radiation Injuries / Q000276:immunology / Q000378:metabolism; D013194:Staining and Labeling; D013997:Time Factors
D000906:Antibodies; D024141:Collagen Type IV; D000939:Epitopes; D020778:Matrix Metalloproteinase 2