In acridinium ester chemiluminescence immunization, acridinium ester is usually used as an indicator to label antibodies, but in fact, acridinium ester can also label antigen. So what is the difference between acridinium ester labeling antigen and labeling antibody?
The acridinium ester-labeled antigen and the labeled antibody are similar in the labeling principle and the final light detection. The difference is mainly in the immunoassay method. Usually acridinium ester-labeled antibody is used for double antibody sandwich assay, and acridinium ester-labeled antigen is used for competition assay.
Chemiluminescence reagent acridinium ester labeled antibody
Double anti-sandwich method:
The double-antibody sandwich method usually detects antigens. There are three immune components: solid-phase antibodies (specific antibodies bound to solid-phase carriers), test samples (ie, antigens that need to be tested), and antibodies labeled with acridinium esters. These three types will form an immune complex with two antibodies sandwiching the antigen. Since the antibodies in the complex are labeled with acridinium ester, the content of the antibody in the complex can be analyzed by chemiluminescence reaction of acridinium ester to calculate the antigen content in the sample to be tested.
Sometimes it is also possible to add a secondary antibody (secondary antibody, antibody of the antibody, which binds to the antigen and does not bind to the antigen) as a solid phase carrier. The primary antibody is fixed on the T line of the test line, and the second antibody is used as the control line C line (quality control line) ), so that when the acridinium-labeled antibody is excessive, it will continue to bind to the secondary antibody. The concentration of the antigen to be tested is analyzed and calculated by the ratio of the luminescence intensity of the acridinium-ester in the test line and the control line.
For example: HIV-1p24, the antigen of AIDS, is the double-antibody sandwich method, which does not use acridinium ester to label the antigen, but to label the anti-p24 antibody.
The competition method can be used to determine the antigen, but also can be used to determine the antibody. For example, for the detection of antigens, the test antigen and the acridinium-labeled antigen can be combined with the solid-phase antibody in a competitive manner. These two antigens have the same chance to bind to the solid-phase antibody, so they are bound to the solid-phase acridinium-labeled antigen. The amount of antigen is inversely proportional to the amount of tested antigen. The acridinium ester-labeled antigen-antibody complex can be measured by chemiluminescence, and the content of the tested antigen can be calculated according to the inverse relationship.
It can be seen that the same is the detection of antigens, one is to label the antibody with acridinium ester, and the other is to label the antigen with acridinium ester. The detection method is different and the labeled objects are different. The antibody detection is similar, and the label is not what is detected. Desheng currently provides six acridinium esters, which can meet the labeling and detection of a variety of different antigens and antibodies.
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