A simple one-step hemolytic assay for C2 with C2-deficient human serum

Area of Science:

• Immunology
• Complement System Biology

Background:

• The complement system is crucial for innate and adaptive immunity.
• Accurate quantification of complement components like C2 is vital for understanding immune responses.
• Existing methods for C2 titration can be complex and time-consuming.

Purpose of the Study:

• To develop a simple, one-step molecular titration assay for complement component 2 (C2).
• To enable the quantification of C2 in various biological samples, including human and animal sera.
• To provide a reproducible and sensitive method for C2 measurement.

Main Methods:

• A novel assay utilizing sheep red blood cells sensitized with specific antibodies (EA) and human serum deficient in C2 (C2D serum).
• Incubation of EA, C2D serum, and test material containing C2 at 37°C for 60 minutes.
• Quantification of C2 by measuring the hemolytic activity restored to C2D serum and calculating lysed cells.

Main Results:

• The assay successfully quantifies C2 in human, guinea pig, rat, mouse, and rabbit sera.
• The method is not effective for C2 titration in dog serum.
• The assay demonstrates simplicity, reproducibility, and sensitivity comparable to conventional two-step assays.

Conclusions:

• A straightforward one-step molecular titration assay for C2 has been established.
• This assay provides a reliable tool for measuring C2 levels across multiple species.
• The developed method offers a valuable advancement for complement research and diagnostics.