Immunoassay

• US 7,638,292 B2
• Filed: 11/13/2007
• Issued: 12/29/2009
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: University of Turku
• Original Assignee: University of Turku
• Inventors: Pettersson, Kim, Eriksson, Susann
• Primary Examiner(s): Gabel; Gailene R
• Application Number:
  US11/979,977
• Publication Number:
  US 20080153109A1
• Time in Patent Office: 777 Days
• Field of Search: 435/4, 435/7.1, 435/7.5, 435/962, 435 792- 795, 435/288.4, 435/967, 435/973, 435/961, 435/971, 436/518, 436/524, 436/528, 436/540, 436/546, 436/548, 436/172, 436/175, 436/517, 436/523, 436/535, 436/538, 436/811, 436/819, 530/403
• US Class Current: 435/7.94
• CPC Class Codes: G01N 2333/4712 Muscle proteins, e.g. myosin, actin, protein
• CPC Class Codes: G01N 33/6887 from muscle, cartilage or connective tissue
• CPC Class Codes: Y10S 435/962 Prevention or removal of interfering materials or reactants or other treatment to enhance results, e.g. determining or preventing nonspecific binding
• CPC Class Codes: Y10S 435/967 Standards, controls, materials, e.g. validation studies, buffer systems
• CPC Class Codes: Y10S 435/973 Simultaneous determination of more than one analyte
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

A method for detection and/or quantification of cardiac troponin I (cTnI) in a sample derived from an individual'"'"'s blood, the method being based on a sandwich immunoassay employing at least two capture antibodies and at least one tracer antibody, in which a first capture antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to the part of the cTnI midfragment, which is slightly affected by the interfering factor, and a second capture antibody is directed to another of these parts, and a tracer antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to TnC, which is complexed with cTnI.

Claims

1. An immunoassay for detection and/or quantification of cardiac troponin I (cTnI) in a sample derived from an individual'"'"'s blood, comprising

contacting said sample with at least two capture antibodies that bind to said cTnI and at least one tracer antibody that binds to said cTnI or to TnC complexed with cTnI,

detecting a signal from said tracer antibody,

comparing said signal against a signal obtained from a standard having a known concentration of cardiac troponin I,

wherein a first capture antibody is directed to the N-terminal portion of cTnI, and

wherein a second capture antibody is directed to the C-terminal portion of cTnI.

2. The immunoassay of claim 1, wherein said tracer antibody is directed to the C-terminal part of cTnI.

3. The immunoassay of claim 2, wherein said second capture antibody is directed to the epitope region 148-209 aa, and said tracer antibody is directed to the epitope 110-148 aa.

4. The immunoassay of claim 3, wherein said second capture antibody is directed to the epitope region 190-196 aa, and said tracer antibody is directed to the epitope 137-148 aa.

5. The immunoassay of claim 1, wherein a third capture antibody is directed to the N-terminal part of cTnI, and said tracer antibody is directed to TnC.

6. The immunoassay of claim 5, wherein said second capture antibody is directed to the epitope region 148-209 aa, and said third capture antibody is directed to the epitope region 1-29 aa.

7. The immunoassay of claim 5, wherein said second capture antibody is directed to the epitope region 190-196 aa, and said third capture antibody is directed to the epitope region 23-29 aa.

8. The immunoassay of claim 1, wherein the capture antibodies are attached to a solid surface and the immunoassay is carried out as a heterogeneous assay.

9. The immunoassay of claim 1, wherein the capture antibodies are attached to a small particle or a molecule, and the method is carried out as a homogeneous assay.

10. The immunoassay of claim 9, wherein the capture antibodies are attached to a molecule, and the homogeneous immunoassay is an energy transfer assay.

11. The immunoassay of claim 9, wherein said molecule comprises a luminescent lanthanide chelate.

12. The immunoassay of claim 1, wherein the sample is serum, plasma or whole blood.

13. The immunoassay of claim 1, with the proviso that the sample is taken and analyzed within 97 hours after presentation of the individual to a health care facility.