An efficient one-step method for isolating immune complexes from whole serum using a monoclonal anti-C3g affinity...

Area of Science:

• Immunology
• Biochemistry
• Analytical Chemistry

Background:

• Immune complexes (IC) play a role in various diseases.
• Efficient extraction and recovery of complement-fixing IC are crucial for diagnostic and research purposes.
• Current methods may have limitations in broad applicability and recovery rates.

Purpose of the Study:

• To develop a simple and efficient method for extracting and recovering complement-fixing immune complexes (IC) from whole serum.
• To compare the efficacy of anti-C3g and anti-C1q immunosorbents for IC extraction.
• To identify the optimal immunosorbent for isolating complement-fixing IC.

Main Methods:

• Development of Sepharose 4B-based immunosorbents covalently linked to monoclonal anti-C3g or anti-C1q antibodies.
• Incubation of 125I-labelled, in vitro prepared IC in whole serum with the immunosorbents.
• Monitoring of IC binding and recovery using radioactivity.
• Elution of bound IC using 4M MgCl2.

Main Results:

• The anti-C3g immunosorbent demonstrated higher binding efficiency for HAGG and BSA-anti-BSA IC (45% and 76%, respectively) with complete recovery.
• The anti-C1q immunosorbent showed lower binding (14% and 12%) and incomplete recovery (64%).
• IC extracted by anti-C3g included those captured by anti-C1q, indicating broader reactivity.

Conclusions:

• The anti-C3g immunosorbent is highly effective for isolating complement-fixing IC due to its wide reactivity and excellent recovery properties.
• Anti-C3g recognizes multiple complement degradation products, enhancing its utility for IC capture.
• This method represents a preferred choice for the isolation of complement-fixing IC in various applications.