Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
1999-12-22
2001-01-16
Le, Long V. (Department: 1641)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C435S007800, C435S007200, C435S007900, C435S007930, C435S007940, C435S970000, C435S973000, C435S007500, C435S975000, C435S960000, C435S961000, C435S091500, C435S091500, C435S091500, C435S091500, C435S091500, C436S825000, C436S056000, C436S808000, C436S541000, C436S816000, C436S901000, C436S169000, C436S533000, C436S170000, C436S530000, C436S810000, C436S525000, C530S388900, C530S389800, C424S010400
Reexamination Certificate
active
06174688
ABSTRACT:
BACKGROUND
This invention relates to assays and more particularly to immunoassays for the detection of antigens.
Presently, immunoassays are capable of detecting only one antigen (if the antibody is cross-reactive, the assay might detect a set of chemically similar antigens). If there are chemical species present in the sample which affect the affinity of the antibody for its antigen (interferants), the results of the assay will change. If the sample is an unknown, there will be no way of realizing that the results of the assay have been compromised. For example, the commercially available immunoassays for petroleum in water use a single conventional test such as a competition immunoassay, to give the petroleum content of water for concentrations in the ppm (parts per million) range. The antibodies in these assays bind a specific constituent of the petroleum, usually BTEX (benzene, toluene, ethylbenzene, and xylene). However, petroleum contains other species (such as alkanes) that change the antibody affinity for the BTEX, and thus change the results of the assay. In the protocol recommended by the manufacturer of these kits, the calibration is performed against a specific petroleum product (i.e., gasoline, kerosene, home heating fuel, etc). This assumes that one knows before hand what type of petroleum product is in the sample. If not, the result of the assay is inaccurate. A modification of the technique to quantify the interferants would be extremely valuable in obtaining additional quantitative information from the assay.
SUMMARY
Accordingly, an object of this invention is to provide a method of accurately quantifying a known antigen and a known interferant in a sample containing a mixture of the antigen and interferant.
Another object of this invention is to provide a method of determining the concentration of a known antigen in the presence of an unknown interferant.
A further object of this invention is to provide a method of determining information about the binding activity of an unknown antigen and an unknown interferant in a sample containing a mixture of the antigen and the interferant.
These and other objects of this invention are achieved by providing
a method for determining the concentrations of a known antigen and a known interferant in a sample comprising:
A. generating a 3-dimensional calibration curve for a competition immunoassay which shows the assay readout for points on a matrix of the antigen concentration versus the interferant concentration;
B. generating a 3-dimensional calibration curve for a non-competition immunoassay selected from the group consisting of inhibition immunoassays and sandwich immunoassays which shows the assay readout for points on a matrix of the antigen concentration versus the interferant concentration:
C. performing the competition immunoassay on the sample using the same conditions and parameters used in generating the 3-dimensional calibration curve in step A to obtain a competition immunoassay readout for the sample;
D. finding the matrix points on the 3-dimensional calibration curve for the competition imunoassay (step A) which have the same readout as the sample (step C) and using the points to form a 2-dimensional curve of the antigen concentration versus the interferant concentration for the competition readout value for the sample;
E. performing the non-competition immunoassay on the sample using the same conditions and parameters used in generating the 3-dimensional calibration curve in step B to obtain a non-competition immunoassay readout for the sample;
F. finding the matrix points on the 3-dimensional calibration curve for the non-competition immunoassay (step B) which have the same readout as the sample (step E) and using the points to form a 2-dimensional curve of the antigen concentration versus the interferant concentration for the non-competition immunoassay readout value for the sample; and
G. finding the point of intersection between the 2-dimensional competition immunoassay curve (step D) and the 2-dimensional non-competition immunoassay curve (step F) and reading the antigen concentration and the interferant concentration corresponding to this point.
If the antigen is known but the interferant is unknown, a substitute known interferant is used with the known antigen to generate the 3-dimensional calibration curves for the competition and the non-competition immunoassays. Otherwise, the method is performed as described above. The resulting matrix point in step G gives the concentration of the known antigen and the concentration of the substitute known interferant which produces the same influence or interference as the unknown concentration of the unknown interferant in the sample.
If the antigen is unknown and the interferant is known. a substitute known antigen is used with the known interferant to generate the 3-dimensional calibration curves for the competition and the non-competition immunoassays. Otherwise, the method is performed as described above. The resulting matrix point in step G gives the interferant concentration and concentration of the substitute known antigen which has the same immunoassay activity as the unknown concentration of the unknown antigen in the sample.
Even if both the antigen and the interferant are unknown, the above method can be adapted to provide some information. A substitute known antigen and a substitute known interferant are used to generate the 3-dimensional calibration curves for the competition and the non-competition immunoassays. Otherwise, the method is performed as described above. The resulting matrix point in step G gives the concentrations of the substitute known antigen and the substitute known interferant which give the equivalent results as the unknown concentrations of the unknown antigen and the unknown interferant in the sample.
REFERENCES:
patent: 3856469 (1974-12-01), Schneider et al.
patent: 4313734 (1982-02-01), Leuvering
patent: 4868132 (1989-09-01), Byrnes et al.
patent: 5158869 (1992-10-01), Pouletty et al.
patent: 5589401 (1996-12-01), Hansen et al.
patent: 5691148 (1997-11-01), Friedman et al.
patent: 5891641 (1999-04-01), Prusiner et al.
Collin Tillyer., “Calibration in three dimensions: Optimizing a two-parameter calibration technique to extend the range of an immunoturbidimetric urinary albumin assay into antigen excess”., Clinical Chemistry, vol.36, No.2, 1990, pp. 307-312.
Cook Lisa V.
Forrest John
Johnson Roger D.
Le Long V.
The United States of America as represented by the Secretary of
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