Project Examples – Development of Multiplexed Immunoassays to Quantitate Human IgG Antibodies to a Polyvalent Bacterial Vaccine

Objective: To develop and optimize a multiplexed immunoassay to quantitate human serum antibodies (IgG and total antibodies) to four bacterial polysaccharides that comprise the client’s polyvalent vaccine.

Specifications: Analytical sensitivity and specificity equal to or greater than the client’s single analyte ELISAs.

Proposed Timeline: 12 Weeks

Description: IBA employed the BioPlex™ multianalyte detection system and optimized the conjugation of the bacterial polysaccharides to four separate bead sets to capture antigen-specific patient antibodies.  Patient antibodies were detected by sequential addition of commercially available anti-human IgG or anti-human Ig immunoreagent conjugated to biotin and strepavidin conjugated to phycoerythrin. 

Antibody quantitation was determined by reference to a multiplexed human serum calibrator containing antibody reactivity to each of the four bacterial polysaccharides.  Anti-IgG and total Ig reactivities in the multiplexed calibrator serum were value assigned based on reference standards.

Results: Multiplexed assay sensitivities and specificities achieved were equal to or better than the single analyte ELISA sensitivities and specificities.

• Total assay time was less than 2 hours.
• Patient serum required for the multiplexed assay was 2 to 5 μL.

 Project Completion: 11 Weeks