Detergent-induced specificity of an antirhodopsin serum for opsin. Micro-complement fixation studies.
An antiserum elicited in rabbit against dark-adapted rod outer segment membranes has been characterized by means of the micro-complement fixation technique. Both particulate rhodopsin and opsin, either biochemically intact or denatured and either membrane-bound or in the absence of lipids, are able to interact with the antiserum. Solubilization of the antigens in increasing concentrations of Emulphogene BC-720 leads to complete loss of complement fixation with both rhodopsin and opsin, but in the case of opsin this requires almost 10-times more detergent. In the case of opsin this masking phenomenon is preceded by a drastic exposure of antigenic sites which in the membrane vesicles are not accessible to the antibodies. Absorption experiments show that the antigenic sites on membrane-bound rhodopsin and opsin, as well as on Emulphogene BC-720-solubilized opsin, are of the same nature. Competition experiments show that the masking effect of the detergent is due to an inhibition of the primary antigen-antibody interaction and not to the inhibition of lattice formation. The use of detergents other than Emulphogene BC-720 further demonstrates that detergents more efficiently mask the antigenicity of conformationally intact than of denatured rhodopsinoids. The balance between the masking and the denaturing efficiency of a particular detergent determines whether a detergent-induced immunological discrimination can be observed between rhodopsin and opsin. The detergent-induced masking effects described are typical for the present antiserum and are probably dependent on methodological details of the immunization procedure.
D000818:Animals; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex; D001059:Apoproteins / Q000276:immunology; D002417:Cattle; D003168:Complement Fixation Tests; D003623:Dark Adaptation; D003902:Detergents; D011487:Protein Conformation; D012168:Retinal Pigments / Q000276:immunology*; D012243:Rhodopsin / Q000276:immunology*; D012374:Rod Cell Outer Segment / Q000276:immunology
D000936:Antigen-Antibody Complex; D001059:Apoproteins; D003902:Detergents; D012168:Retinal Pigments; D012243:Rhodopsin