Enzyme immunoassays using immobilized reagents in a flowing stream
First Claim
1. A method for quantitatively determining the amount of an antigen contained in a biochemical fluid comprising obtaining sample of said fluid and mixing it in a mixing zone with an aqueous solution, passing said sample-solution into a solubilization stage containing an immobilized antibody which is specific to said antigen, said immobilized antibody initially having an immunochemically equivalent amount of reversibly bound an antigen-enzyme complex wherein said antigen of said complex is the same as the antigen in the sample, maintaining said sample-solution in said solubilization stage for a period of time and under conditions sufficient for a competitive equilibrium reaction to take place between the said antigen and said bound antigen complex, thereby displacing a quantity of said bound antigen complex from said immobilized antibody into said sample-solution;
- passing said complex-containing sample-solution into a conversion stage containing a substrate capable of reacting with said enzyme of said complex to produce a measurable reaction product in said sample-solution;
passing said measurable reaction product-containing sample-solution into a detection stage wherein said measurable reaction product is quantitatively measured to obtain a reading, and comparing said measured reading to the quantitative amount of antigen in said original sample.
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Abstract
This invention relates to a method and apparatus for the rapid quantitative determination of an antigen contained in aqueous biochemical samples, for example, blood. The method comprises a series of sequentially arranged stages through which a buffered stream flows. The sample, containing an unknown concentration of the antigen, is injected into the buffered flowing stream and contacts various reagents in the sequential series of stages. An initial solubilization stage comprises an immobilized antibody on a substrate which antibody is specific to the antigen in the sample. The immobilized antibody has been reacted previously to saturation with an enzyme-antigen complex, the antigen of the complex being the same as the antigen in the sample, and the complex is reversably bound to the immobilized antibody. The antigen in the sample and buffered stream flow through the solubilization stage and a competitive equilibrium reaction takes place between the complex bound to the antibody and the antigen in the sample, resulting in the release of a quantity of the enzyme-antigen complex into the flowing stream. The complex and the stream pass into a conversion stage wherein the complex reacts with an immobilized substrate, such as starch, to produce a measurable product which is a quantitative index of the complex released in the solubilization stage. The measurable product and the stream flow to a detection stage wherein the product is reacted, quantitatively measured and related to the concentration of the antigen in the original sample.
57 Citations
24 Claims
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1. A method for quantitatively determining the amount of an antigen contained in a biochemical fluid comprising obtaining sample of said fluid and mixing it in a mixing zone with an aqueous solution, passing said sample-solution into a solubilization stage containing an immobilized antibody which is specific to said antigen, said immobilized antibody initially having an immunochemically equivalent amount of reversibly bound an antigen-enzyme complex wherein said antigen of said complex is the same as the antigen in the sample, maintaining said sample-solution in said solubilization stage for a period of time and under conditions sufficient for a competitive equilibrium reaction to take place between the said antigen and said bound antigen complex, thereby displacing a quantity of said bound antigen complex from said immobilized antibody into said sample-solution;
- passing said complex-containing sample-solution into a conversion stage containing a substrate capable of reacting with said enzyme of said complex to produce a measurable reaction product in said sample-solution;
passing said measurable reaction product-containing sample-solution into a detection stage wherein said measurable reaction product is quantitatively measured to obtain a reading, and comparing said measured reading to the quantitative amount of antigen in said original sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- passing said complex-containing sample-solution into a conversion stage containing a substrate capable of reacting with said enzyme of said complex to produce a measurable reaction product in said sample-solution;
- 16. An apparatus for the quantitative determination of an antigen contained in an aqueous biochemical sample, comprising in combination, a reservoir containing a buffer diluent solution, mixing means for said diluent solution and said sample after they are combined, solubilization means to receive the mixed diluent solution and sample containing immobilized antibody initially saturated with an immunochemically equivalent amount of antigen-enzyme complex reversibly bound thereon, conversion means to receive the stream from the solubilization means containing immobilized reagent capable of reacting with said complex to produce a measurable reaction product, detection means capable of monitoring said measurable reaction product to produce a reading relatable to the amount of said antigen.
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23. A method for determining the presence of an antigen in a biochemical fluid, comprising:
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a. contacting a sample of said fluid with an immobilized antibody specific to said antigen, said antibody initially having bound thereto an immunochemically equivalent amount of enzyme-antigen complex, the antigen of said complex corresponding to said antigen, b. equilibrating said sample and said immobilized antibody under conditions sufficient to replace enzyme-antigen complex bound to said immobilized antibody with said antigen and thereby liberating a portion of said bound complexes c. reacting said liberated enzyme-antigen complex with a reactive substrate to produce a detectable product, and d. detecting the presence of said product. - View Dependent Claims (24)
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Specification