Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
2000-01-27
2002-10-29
Saunders, David (Department: 1644)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C435S287200, C435S287600, C435S287700, C435S970000, C436S501000, C436S514000, C436S518000
Reexamination Certificate
active
06472160
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an immunoassay device to be used for detecting an antigen or antibody in a specimen, and an immunoassay method using the same.
This invention also relates to an immunoassay method which comprises adding a specimen to an immunoassay device in which a labeling reagent zone comprising a labeled genetic recombinant syphilis treponeme (
Treponema pallidum,
hereinafter referred to as “TP”) antigen and a detection zone in which a TP antigen is immobilized to a matrix which can transfer a solution by capillarity are provided on the matrix; and detecting an anti-syphilis treponeme antibody (hereinafter referred to as “the anti-TP antibody”) in the specimen which is bound to the detection zone, and an immunoassay device to be used for said assay.
As a device which detects an antigen or antibody in a specimen simply and easily, an immunoassay device has been used. A conventional immunoassay device is schematically shown in
FIG. 11
(see Japanese Provisional Patent Publication No. 47894/1978). The conventional immunoassay device has a membrane portion
20
comprising a material such as cellulose, and a developing solution-supplying portion
22
and an absorption portion
24
each comprising a water-absorbable material, provided at both ends of the membrane portion
20
, respectively. In the membrane portion
20
, a labeled substance dotting portion
26
to which a labeled substance labeled with a radioisotope is dotted is provided. Further, a detection line
28
is provided between the labeled substance dotting portion
26
and the absorption portion
24
. At the detection line
28
, an antibody or antigen which reacts with an antigen or antibody to be detected is immobilized to a membrane. Further, between the labeled substance dotting portion
26
and the developing solution-supplying portion
22
, a specimen dotting portion
29
is provided.
When the device is used, a specimen solution is added to the specimen dotting portion
29
, and a developing solution is added to the developing solution-supplying portion
22
. The developing solution is developed from the developing solution-supplying portion
22
and reaches to the specimen dotting portion
29
. The specimen dotted to the specimen dotting portion
29
is flowed by the developing solution flowing from the developing solution-supplying portion
22
, reaches to the labeled substance dotting portion
26
and reacts with the labeled substance. When the reaction mixture is further flowed by the developing solution and reaches to the detection line
28
, an antigen or antibody in the specimen is trapped by an antibody or antigen immobilized to the detection line
28
and held there. In this case, the antigen or antibody in the specimen is bound to the labeled substance so that the labeled substance is also held at the detection line
28
. Therefore, when the antigen or antibody to be detected is contained in the specimen solution, the signal of the radioisotope is observed on the detection line
28
. The developing solution and other components which are not trapped are absorbed into the absorption portion
24
. On the other hand, when the antigen or antibody to be detected is not contained in the specimen solution, the labeled substance is not trapped at the detection line
28
and therefore is absorbed as such into the absorption portion
24
, whereby the signal is not observed on the detection line
28
. Thus, whether or not the antigen or antibody to be detected is contained in the specimen can be found by whether or not the signal of the radioisotope is detected at the detection line
28
.
However, in the conventional immunoassay device as described above, there are problems that since the specimen dotted to the specimen dotting portion
29
is diluted with the developing solution during measurement, lowering of detection sensitivity is caused, and since the labeled substance is dissolved in the developing solution during development and reacts with the specimen, when an object to be measured has low concentration, in order to carry out an accurate test, a long reaction time is required to be taken.
An immunoassay device using a color latex has been also known. In this device, color latex particles to which an antibody or antigen which reacts with an antigen or antibody to be detected is bound are used as a labeled substance. This device is schematically shown in
FIG. 4. A
labeled substance dotting portion
32
is provided at one end of a membrane portion
30
, and the above labeled substance is contained in the labeled substance dotting portion
32
. On the other hand, to a detection line
36
is immobilized an antibody or antigen which reacts with an antigen or antibody to be detected. A specimen solution is added to a sample dotting portion
34
in the labeled substance dotting portion
32
. The specimen solution and the labeled substance dissolved by the specimen solution are flowed while they are reacted, and when an antigen or antibody to be detected is contained in the specimen solution, the labeled substance is trapped at the detection line
36
as in the above case. The labeled substance contains a color latex so that the detection line
36
is colored. On the other hand, when the antigen or antibody to be detected is not contained in the specimen solution, the labeled substance is not trapped at the detection line
36
so that the detection line
36
is not colored. Thus, whether or not the antigen or antibody to be detected is contained in the specimen solution can be found by whether or not the detection line
36
is colored.
However, in the conventional immunoassay devices, there is a problem that a result which was negative at the time of judgment may be changed to be positive with a lapse of time. Therefore, when plural specimens are judged under the same conditions, it is necessary to carry out judgment at a certain judgment time or carry out judgment after a reaction is terminated by adding a reaction-terminating solution after a lapse of a certain period of time. However, when a large number of specimens are tested in parallel as in clinical tests, it is difficult to carry out judgment of all specimens at the same judgment time or add a reaction-terminating solution after a lapse of the same period of time. Further, when a reaction-terminating solution is added, the number of steps is increased to make an operation troublesome.
It is important to analyze living body components or drugs contained in blood, urine and the like for diagnosis of conditions of diseases and judgment of progress after therapy. As a method for analyzing these living body components, drugs and the like from a specimen simply and easily by utilizing an antigen-antibody reaction, there has been found a method of using a strip assay device comprising a strip-shaped filter paper impregnated with a reaction reagent. This assay method is a method in which a specimen is added to a specimen dotting zone provided on the filter paper of the device, a solution is developed and diagnosis is carried out from the degree of coloring shown at a detection zone provided on the filter paper. In the above strip assay device, a filter paper containing a necessary reagent (an enzyme-labeled antibody, a substrate, a coloring reagent or the like) depending on the system of a reaction is used, and analysis is carried out from coloring thereof so that a simple and easy method can be carried out without using a special judgment device. Also, there has been known an assay method of using a color latex or particles of metal colloid or the like as a labeled substance. In this assay method, analysis is carried out by using a reagent in which an antibody or antigen which reacts with an antigen or antibody to be detected is bound to particles and detecting the image of the particles bound to a detection zone.
In the prior art, as a method for detecting the anti-TP antibody, there have been known a method of using a TPHA reagent in which a TP cell component is bound to hemocytes, a method of using an indirect agglu
Ashihara Yoshihiro
Hasegawa Akira
Ishioka Yuko
Isomura Mitsuo
Saruta Hiroko
Fujirebio Inc.
Saunders David
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