Purchase this article with an account.
L. A. Kuttner-Kondo, L. Hong, R. G. Salomon, J. G. Hollyfield; Antibody Mapping of Complement C3 Binding to CEP-BSA. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4942.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Carboxyethyl pyrrole (CEP), an oxidation product of docosahexaenoic acid that is found adducted to proteins in drusen and plasma, may directly activate the alternative pathway of complement. This study was undertaken to localize the binding site of CEP adducted bovine serum albumin (CEP-BSA) on complement component C3 and begin an examination of the nature of the binding using the methyl ester of CEP-BSA for comparison.
Sham-adducted BSA (BSA) or CEP-BSA was coated on ELISA plates. Subsequently, C3 fragments C3b, iC3b, C3c and/or C3d were added in equimolar quantities. Binding was assessed using a panel of anti-C3 monoclonal antibodies (mAbs) with specificity for C3c, C3d or neo-antigens.
An anti-C3c mAb clearly demonstrated the ability of C3b and iC3b to bind CEP-BSA. MAbs that recognize epitopes in C3d showed that C3d also binds CEP-BSA. In contrast, binding of these C3 fragments to BSA appears to be minimal. Using one anti-C3d mAb, C3d incubated on a Medisorp surface coated with either CEP-BSA or a methyl ester of CEP-BSA was detected at similar levels.
These findings provide a basis for investigating a potential role of CEP-adducted protein in alternative pathway complement activation. As the methyl ester removes the carboxyl group, this opens up a possible role for the pyrrole ring in binding.
This PDF is available to Subscribers Only