A specific ELISA using purified opsin, for studying autoimmunity in retinal diseases

Area of Science:

• Biochemistry
• Immunology
• Ophthalmology

Background:

• Rhodopsin and its apoprotein, opsin, are key proteins in retinal rod outer segments (ROS).
• Accurate quantification of these proteins is crucial for understanding retinal diseases and autoimmunity.
• Existing methods may lack the sensitivity required for detecting minute quantities.

Purpose of the Study:

• To develop a highly sensitive enzyme-linked immunosorbent assay (ELISA) for measuring nanogram quantities of rhodopsin and opsin.
• To compare the immunoreactivity of purified opsin versus opsin within ROS preparations.
• To investigate the effect of sodium dodecyl sulphate (SDS) on ELISA performance.

Main Methods:

• Development of a sensitive ELISA using anti-opsin anti-sera.
• Preparation of purified opsin via quantitative elution from polyacrylamide gel.
• Testing ELISA sensitivity with purified opsin and ROS preparations.
• Evaluation of SDS impact on antigen binding and immunoreactivity.
• Development of a similar ELISA for S-antigen detection.

Main Results:

• The developed ELISA could detect as little as 4 ng of purified opsin or opsin in ROS.
• Purified opsin exhibited higher immunoreactivity than opsin in ROS preparations.
• Concentrations of 0.1% SDS and above significantly reduced opsin-anti-opsin binding.
• A sensitive ELISA for S-antigen was also established, with results confirmed by immunoblotting.

Conclusions:

• Purified opsin is preferable to ROS for ELISA-based detection of rhodopsin autoimmunity in retinal diseases.
• The developed sensitive ELISA techniques are valuable for quantifying rhodopsin, opsin, and S-antigen in various retinal preparations.
• These methods offer potential for diagnosing and studying retinal conditions.