Development of Allergy Test by SPR Imaging Sensor with a Drop of Patientʼs Serum

The identification of antigen that induces activation of mast cells and basophils in a patient is crucial to avoid symptoms of allergic diseases. Since surface plasmon resonance imaging (SPRI) can visualize activation of individual cell, such as basophils without any labeling, SPRI sensor possesses a great potential for clinical diagnosis of allergy. However, conventional technique of SPRI requires freshly isolated basophils of patients and cannot analyze multiple samples in parallel. To overcome such problems, we developed devices for SPRI to make a broad observation area and a multi-well SPRI sensor chip with a hydrophobic membrane. The employment of human IgE receptor-expressing mast cell lines (RBL-48 cells) sensitized with serum, collected and stored from less than a microliter of patient ʼ s blood, allowed us to detect specific reactions of RBL-48 cells in response to antigens, suggesting this technique may be a useful tool as a screening system of type I allergy.