Immunoassays for prostate specific antigen
AssigneeAbbott Laboratories
InventorsBarry L. Dowell, Carol A. King, Debra B. Alexander, Allan H. Smith, Susan B. O'Morchoe
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Abstract
The present invention relates to the field of cancer immunoassay. Specifically, a new immunoassay method for prostate specific antigen (PSA) is presented. Also presented is a complex which resembles a complex of PSA and .alpha.-antichymotrypsin (ACT) that can be used as a calibrator or control in an immunoassay for PSA. Further presented is a method for fractionating polyclonal antibodies, to PSA, into those which bind epitopes that are masked by the binding of PSA to ACT and those which do not bind such epitopes.
Claims33
An immunoassay method for detecting or quantitating an Analyte ("A") in a sample, the Analyte being capable of existing in the sample in a free form ("free Analyte") or bound to a Binding Molecule to form a complex of the Analyte and the Binding Molecule ("{(A)(Binding Molecule)}"), the method comprising the steps of:
- (a) contacting the Analyte to an antibody (".alpha.HE") which can bind the free Analyte but not {(A)(Binding Molecule)}, a capture antibody (".alpha.nHE") which can bind both the free Analyte and {(A)(Binding Molecule)}, and a probe antibody (".alpha.A*") specific for the Analyte, providing that if the probe antibody is a polyclonal antibody then the Analyte is contacted to the capture antibody before the probe antibody;
- (b) correlating the presence or amount of .alpha.A* which is bound to the Analyte, with the presence or amount of the Analyte in the sample, or correlating the amount of unbound .alpha.A* with the absence or amount of the Analyte in the sample.
A kit for conducting an assay for Analyte in a sample, wherein the Analyte can exist in the sample as a free Analyte or bound to a Binding Molecule to form a complex of Analyte-Binding Molecule Complex, the kit comprising the following:
- (a) a first container containing an antibody (.alpha.HE) specific to the Analyte which can bind to the free Analyte but not Analyte-Binding Molecule Complex;
- (b) a second container containing a capture antibody specific for the Analyte;
- and
- (c) a third container containing a probe antibody specific for the Analyte.
A kit for conducting an assay for Analyte in a sample, wherein the Analyte can exist in the sample as a free Analyte or bound to a Binding Molecule to form a complex of Analyte-Binding Molecule Complex, the kit comprising the following:
- (a) a first container containing:
- (i) a capture antibody specific for the Analyte, and
- (ii) an antibody (.alpha.HE) specific to the Analyte which can bind the free Analyte but not the Analyte-Binding Molecule Complex;
- and
- (b) a second container containing a probe antibody specific for the Analyte.
A kit for conducting an assay for Analyte in a sample, wherein the Analyte can exist in the sample as a free Analyte or bound to a Binding Molecule to form a complex of Analyte-Binding Molecule Complex, the kit comprising the following:
- (a) a first container containing a capture antibody specific for the Analyte;
- and
- (b) a second container containing:
- (i) an antibody (.alpha.HE) specific to the Analyte which can bind the free Analyte but not the Analyte-Binding Molecule Complex, and
- (ii) a probe antibody specific for the Analyte.
An immunoassay method for detecting or quantitating an Analyte ("A") in a sample, the Analyte being capable of existing in the sample in a free form ("free Analyte") or bound to a Binding Molecule to form a complex of {(A)(Binding Molecule)}, the method comprising the steps of:
- (a) incubating the sample with polyclonal capture antibodies (".alpha.A") which contain antibodies which bind the free Analyte and antibodies which bind {(A)(Binding Molecule)};
- (b) incubating the sample with an antibody .alpha.HE capable of binding free analyte but not {(A) (Binding Molecule)} for a sufficient time for the .alpha.HE to bind to the Analyte;
- (c) incubating the sample with a probe antibody (".alpha.nHE*") capable of binding both the free Analyte and {(A)(Binding Molecule)};
- and
- (d) correlating the presence or amount of .alpha.nHE* bound to the Analyte with the presence or amount of Analyte in the sample;
- or correlating the amount of unbound .alpha.nHE* with the absence or amount of the Analyte in the sample.
An immunoassay method for defecting or quantitating Analyte ("A") in a sample, the Analyte being capable of existing in the sample in a free form ("free Analyte") or bound to a Binding Molecule to form a complex of {(A)(Binding Molecule)}, the method comprising the steps of:
- (a) incubating the sample with a capture antibody (".alpha.nHE") which can bind both free Analyte and {(A)(Binding Molecule)}, for a sufficient time for the capture antibody to bind to any Analyte and {(A)(Binding Molecule)} that may be present in the sample to form complexes of {(.alpha.nHE)(A)} and {(.alpha.nHE)(A)(Binding Molecule)}, respectively;
- (b) incubating the sample with an antibody .alpha.HE which can bind the free Analyte but not {(A) (Binding Molecule)} for a sufficient time for the .alpha.HE to bind to the Analyte;
- (c) incubating the sample with a probe antibody (".alpha.A*") specific for the Analyte for a sufficient time to bind to the Analyte;
- (d) detecting the presence or amounts of the complexes of {(.alpha.nHE)(A)(.alpha.HE)(.alpha.A*)} and {(.alpha.nHE)(A)(Binding Molecule)(.alpha.A*)}, or free .alpha.A*;
- and
- (e) correlating the presence or amounts of {(.alpha.nHE)(A)(.alpha.HE)(.alpha.A*)} and {(.alpha.nHE)(A)(Binding Molecule)(.alpha.A*)} with the presence or amount of the Analyte in the sample;
- or correlating the amount of free .alpha.A* with the absence or amount of the Analyte in the sample.
Dependencies are inferred from the claim text.