Quantitative quality control of antiglobulin reagents

Area of Science:

• Immunology
• Biochemistry

Background:

• Polyspecific antiglobulin reagents are crucial in serological testing.
• Quantifying specific antibody content and binding affinity is essential for reagent quality control.

Purpose of the Study:

• To develop and validate double antibody radioimmunoassays for quantifying anti-IgG, anti-C3, anti-C3c, anti-C3d, and anti-C4 antibodies.
• To determine the binding constants of these antibodies.
• To assess the quality and potency of commercial and public antiglobulin reagents.

Main Methods:

• Development of double antibody radioimmunoassays.
• Quantification of anti-IgG, anti-C3, anti-C3c, anti-C3d, and anti-C4 antibodies in 53 polyspecific antiglobulin reagents.
• Determination of antibody binding constants.
• Comparison of quantitative assay results with serological potency assessments.

Main Results:

• Significant variations in antibody concentrations were observed across commercial and public reagents.
• Public reagents showed a wider range of concentrations, particularly for anti-C3 and anti-C3c.
• Mean binding constants for commercial anti-IgG, anti-C3, anti-C3c, anti-C3d, and anti-C4 were determined.
• Suboptimal concentrations of anti-IgG, anti-C3, and anti-C3c were found in several reagents, potentially impacting agglutination efficacy.

Conclusions:

• The developed radioimmunoassays effectively quantify specific antibodies and their binding constants in antiglobulin reagents.
• There is considerable variability in the composition and potency of antiglobulin reagents from different sources.
• Quality control measures are necessary to ensure reagents contain adequate antibody concentrations for reliable serological testing.