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Toronto, Canada

Jakobsche C.E.,Clark University | Parker C.G.,Scripps Research Institute | Tao R.N.,Yale University | Kolesnikova M.D.,Axela Inc | And 2 more authors.
ACS Chemical Biology | Year: 2013

The ability to profile the prevalence and functional activity of endogenous antibodies is of vast clinical and diagnostic importance. Serum antibodies are an important class of biomarkers and are also crucial elements of immune responses elicited by natural disease-causing agents as well as vaccines. In particular, materials for manipulating and/or enhancing immune responses toward disease-causing cells or viruses have exhibited significant promise for therapeutic applications. Antibody-recruiting molecules (ARMs), bifunctional organic molecules that redirect endogenous antibodies to pathological targets, thereby increasing their recognition and clearance by the immune system, have proven particularly interesting. Notably, although ARMs capable of hijacking antibodies against oligosaccharides and electron-poor aromatics have proven efficacious, systematic comparisons of the prevalence and effectiveness of natural anti-hapten antibody populations have not appeared in the literature. Herein we report head-to-head comparisons of three chemically simple antigens, which are known ligands for endogenous antibodies. Thus, we have chemically synthesized bifunctional molecules containing 2,4-dinitrophenyl (DNP), phosphorylcholine (PC), and rhamnose. We have then used a combination of ELISA, flow cytometry, and cell-viability assays to compare these antigens in terms of their abilities both to recruit natural antibody from human serum and also to direct serum-dependent cytotoxicity against target cells. These studies have revealed rhamnose to be the most efficacious of the synthetic antigens examined. Furthermore, analysis of 122 individual serum samples has afforded comprehensive insights into population-wide prevalence and isotype distributions of distinct anti-hapten antibody populations. In addition to providing a general platform for comparing and studying anti-hapten antibodies, these studies serve as a useful starting point for the optimization of antibody-recruiting molecules and other synthetic strategies for modulating human immunity. © 2013 American Chemical Society.

Lin Y.,Axela Inc | Fu Q.,Johns Hopkins University | Zhu J.,Johns Hopkins University | Miller J.M.,Johns Hopkins University | Van Eyk J.E.,Johns Hopkins University
Clinical Chemistry | Year: 2010

BACKGROUND: With myocardial infarction (MI), cardiac troponin is released from the heart into circulation, where it can be detected with immunoassays independently quantifying cardiac troponin I (cTnI) or cTnT. There is, however, no single immunoassay that sequentially probes the posttranslational modification status of cTnI or directly characterizes whether circulating cTnI is bound to cTnC and/or cTnT. Here we describe the development of a qualitative immunoassay to directly probe the primary and ternary structure of circulating cTnI through diffractive optics technology (dotLab® System, Axela). METHODS: Anti-cTnI antibody 8I-7 was immobilized on a patterned sensor to capture cTnI. One or more detector antibodies were sequentially introduced to probe for amino acid sequence integrity or phosphorylation status of cTnI, or its association with cTnC and/or cTnT. Respective immunocaptures were recorded as real-time diffractive intensities (DIs), and the DI differences were analyzed. Each immunodetection was independent of the others but was done in a single sequential assay. RESULTS: This diffraction-based immunoassay successfully characterized cTnI. The unamplified assay determined whether cTnI was degraded at N-terminus and/or C-terminus or phosphorylated. Sequential application of multiple detector antibodies without an antibody-stripping step enables real-time interrogation of 5 different epitopes of cTnI, or direct detection of the cTn complex (cTnI-cTnC-cTnT) in a single sequential assay. Finally, this assay was optimized with amplification to directly detect circulating cTnI bound to cTnC and cTnT in serum from an MI patient. CONCLUSIONS: The dot® Immunoassay is the first qualitative sequential immunoassay to address the direct interactions of the troponin subunits and various modified forms of cTnI. © 2010 American Association for Clinical Chemistry.

The present invention provides disposable, semi-reusable, or single use reaction vessels with integrated optical elements for use with diffraction based assay systems. The vessel for assaying liquids for analytes includes a housing having at least one chamber or well for receiving a liquid therein and an optical element integrally formed with the housing for directing an incident light beam towards the well or chamber and directing a light beam away from the chamber after the light beam has interacted with analytes present in the liquid. The vessel may be test tube such as a blood collection tube, with or without, an optical element but having a pattern of analyte-specific receptors located on an inner surface of the tube wall so that when a liquid is introduced into the interior of the test tube analytes present in the liquid can bind with the pattern of analyte-specific receptors.

Axela Inc | Date: 2010-10-28

The present invention relates to a method and apparatus for detecting analytes in a medium, and more particularly the present invention relates to an assay based on light diffraction which appears or changes upon the binding of analytes to their specific receptors laid out in patterns on a substrate, which has high sensitivity due to the appropriate choice of such patterns. The present invention is based on the principle that the pattern of recognition elements, which gives rise to the diffraction of the incident light in a diffraction-based assay, can be chosen in such a way so as to facilitate detection, and to enhance the signal to be detected compared to known gratings such as parallel straight lines. In one aspect the substrate itself has a surface topography designed to enhance the diffraction pattern signals. In another aspect the substrate is a diffractive optic element having the analyte-specific receptors affixed to the optic element. In another aspect the diffractive optic element is used as a master stamp for producing patterns of analyte-specific receptors which give the signal enhancements.

The present disclosure provides a diffraction based biosensor containing at least two diffraction gratings. The first grating is referred to as an in-coupling diffraction grating and the coherent light source (laser) is directed to illuminate the in-coupling grating, and the biosensor is configured such that a selected order of the light beam diffracted from the in-coupling diffraction grating illuminates a second biosensor grating coated with analyte-specific receptors which are selected to preferentially bind with analytes being tested for that may or may not be located in a sample being tested.

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