D3.385 - A Synthetic Serum Comprising Human IgE Monoclonal Antibodies to Peanut Allergens

Sera from allergic patients are commonly used for research and diagnostic purposes. Samples containing allergen-specific IgE at useful levels are often in short supply. Endogenous proteins and other components in serum can interfere with analytical methods. A synthetic alternative to human sera offers researchers a consistent reagent with defined allergen-specific IgE levels.

Human IgE monoclonal antibodies (hIgE mAb) were cloned from PBMCs of peanut-allergic patients. Reactivity to Ara h 1 (clone 3B10), Ara h 2 (clone 38B7), Ara h 3 (clone 3C3), and Ara h 6 (clone 15C2) was confirmed using ELISA and immunoblotting. ImmunoCAP was used to measure total and specific IgE concentration. The synthetic serum was prepared using defined concentrations of hIgE mAb in a matrix formulated to be comparable to human serum regarding viscosity, relative density, and osmolality.  

The synthetic serum contained high levels of specific IgE to Ara h 1, Ara h 2, Ara h 3, and Ara h 6 (~5,000 – 7,000 kU/L) and was stable over a period of three months stored at 4^oC. ELISA titration curves for the synthetic serum and sera from a peanut-allergic patient demonstrate parallelism, suggesting similar IgE-allergen binding characteristics.

A synthetic serum containing levels of human IgE 50-70 times higher than CAP Class 6 has been developed. The synthetic serum is free from proteins and other natural serum components that potentially interfere with in vitro testing, providing a novel alternative to patient-derived sera for research and allergy diagnostic purposes.