title: Distribution of complement anaphylatoxin receptors and membrane-bound regulators in normal human retina.
abstract: To characterize the distribution of membrane-bound components of the complement system in normal human retina, eyes from eight human donors with no history of ocular disease, ranging in age from 47 to 85 years were examined using immunohistochemistry to localize the C3a receptor (C3aR), C5a receptor (C5aR), CD46, CD55, and CD59 in cryosections prepared from donor posterior segments. The C3aR was identified in the nerve fiber layer in a sawtooth-patterned band. Vimentin, used as a Müller cell marker, produced a similar staining pattern. The C5aR was detected on specific rounded structures in the inner plexiform layer and occasionally in the nerve fiber layer. CD46 produced markedly specific staining of the basolateral surface of the retinal pigment epithelium. CD55 was localized to the nerve fiber layer. Staining for these proteins was consistent across all eyes studied. CD59 was expressed throughout the nerve fiber layer and labeled vessels that extended through the ganglion cell, inner plexiform, and inner nuclear layers, but this pattern was only confirmable in a single subject. Complement anaphylatoxin receptors and regulatory proteins are localized in different but internally consistent patterns in normal adult human retina, independent of the age of the donor. C3aR and C5aR localization only in the inner retina contrasts with previously reported findings in the central nervous system of wide spread diffuse staining. The complement regulators CD55 and CD59 were found primarily on the inner retina, while CD46 was present exclusively in a polarized fashion on the RPE.
authors.affiliation: Department of Ophthalmology, University of Alabama at Birmingham, 1530 3rd Avenue South, 35294, USA.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Vogt
authors.forename: Scott R
authors.initials: SR
authors.lastname: Barnum
authors.forename: Christine A
authors.initials: CA
authors.lastname: Curcio
authors.forename: Russell W
authors.initials: RW
authors.lastname: Read
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D018958:CD55 Antigens / Q000378:metabolism; D018957:CD59 Antigens / Q000378:metabolism; D003176:Complement C3 / Q000378:metabolism; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051916:Membrane Cofactor Protein / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000378:metabolism; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*
chemical_list: C038245:C3 protein, human; C488033:C5AR1 protein, human; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; D003176:Complement C3; D051916:Membrane Cofactor Protein; D008565:Membrane Proteins; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement