Cross-species serum antibody detection by direct immunoglobulin catalysis

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Current medical practice to diagnose Lyme disease by observation of symptoms combined with blood testing produces a lot of errors. The long-term goal is to develop a new approach that overcomes this limitation in Lyme disease testing and to create a general (cross­species) test for Lyme disease that can be used in humans, pets, livestock, and wild animals. The proposed research takes advantage of a largely-unknown property of the antibodies that form in response to Lyme infection that can be conveniently measured by their chemical reactivity. Lyme disease is the most common vector­borne disease in the United States, infecting 300,000 Americans per year. Current medical practice is to diagnose Lyme disease by observation of symptoms combined with serological detection of the host animal's antibodies against Borrelia antigens using ELISA and Western blot. Both of them have their limitations, namely, the secondary reagents exhibit nonspecific binding. The secondary antibodies make the test specific to the species providing the serum. Inexpensive, isotype- and species-independent antibody sensors are important because they can facilitate widespread monitoring of infectious disease, the cross-species study of the dynamics of seroconversion and early detection following exposure. The long-term goal is to implement and standardize a new biosensor based on direct measurement of antibody catalysis via the antibody-catalyzed water oxidation pathway (ACWOP). The objective is to elucidate the physiochemistry of antigen immobilization and catalytic sensing which produces hydrogen peroxide for a colorimetric or electrochemical readout. Three research aims will be pursued; namely, experimentally show antigen localization and specific antibody binding on paper substrates; show ELISA-level sensitivity from direct catalytic readout of bound antibodies; and, show detection of Borrelia antigens in clinically relevant samples. The key features are novel ACWOP-transduction mechanism that eliminates secondary antibodies from immune-specific sensors and practical implementation of immobilization chemistry that is resistant to nonspecific binding. It is anticipated that the proposed biosensor will have a significant practical impact because species­independent detection of Lyme borreliosis enables monitoring of the Borrelia reservoir as well as livestock, companion animals, and humans.