Differential localization of type IV collagen in Bruch's membrane of the eye: comparison of two polyclonal antibodies.
The ultrastructural localization of type IV collagen in the basal lamina of the retinal pigment epithelium (RPE) and choriocapillary endothelium (CCE) of the rat eye was studied using a pre-embedding immunoperoxidase and a post-embedding immunogold method. Antibodies to type IV collagen from human placenta and from murine Engelbreth-Holm-Swarm (EHS) sarcoma were used with both methods. In the preembedding method, both antibodies were localized to the basal lamina of the RPE and CCE. In the postembedding method, antibody to EHS tumor collagen was also localized to both basal laminae. However, when the latter method was used with antibody to placental collagen, much less labeling was seen in the basal lamina of the RPE compared with that in the CCE. The findings suggest that in the basal lamina of the RPE (but not the CCE), the strongly immunogenic 7S domain of type IV collagen is inaccessible to antibodies directed against this protein. This effect may be due to masking of the 7S domain by other components or to a conformational change in the collagen molecule.
Lin
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WL
Department of Oral Biology, School of Dental Medicine, State University of New York, Buffalo 14214.
Essner
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D000818:Animals; D000906:Antibodies; D016570:Bruch Membrane / Q000648:ultrastructure*; D002196:Capillaries; D002829:Choroid / Q000098:blood supply; D003094:Collagen / Q000032:analysis*; D004730:Endothelium, Vascular / Q000648:ultrastructure; D005260:Female; D007124:Immunoenzyme Techniques; D008297:Male; D016253:Microscopy, Immunoelectron / Q000379:methods; D010857:Pigment Epithelium of Eye / Q000648:ultrastructure*; D010920:Placenta; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012171:Retinal Vessels
D000906:Antibodies; D003094:Collagen