[Script Info]
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[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0000,0000,0000,,(English captions by Andrea Matsumoto, University of Michigan.) Many simple rapid diagnostic tests detect\Nspecific antigens in biological samples by
Dialogue: 0,0:00:05.00,0:00:08.00,Default,,0000,0000,0000,,using an enzyme immunoassay.
Dialogue: 0,0:00:08.00,0:00:14.00,Default,,0000,0000,0000,,The purpose of this animation is to explain\Nhow a prototype of this assay works.
Dialogue: 0,0:00:14.00,0:00:19.00,Default,,0000,0000,0000,,The enzyme immunoassay can be done in a multi-well\Nmicrotiter plate or on any other solid adherence
Dialogue: 0,0:00:19.00,0:00:20.00,Default,,0000,0000,0000,,surface.
Dialogue: 0,0:00:20.00,0:00:25.00,Default,,0000,0000,0000,,I will use the microtiter plate in this example\Nso, lets take a closer look at one of the wells
Dialogue: 0,0:00:25.00,0:00:30.00,Default,,0000,0000,0000,,of this assay to see what happens during the\Nperformance of the assay.
Dialogue: 0,0:00:30.00,0:00:35.00,Default,,0000,0000,0000,,The plate is prepared to perform a particular\Nassay by coating the wells with antibodies
Dialogue: 0,0:00:35.00,0:00:37.00,Default,,0000,0000,0000,,that bind to the antigen of interest.
Dialogue: 0,0:00:37.00,0:00:42.00,Default,,0000,0000,0000,,Then the wells are filled with the clinical\Nsample, which could be a sample of serum,
Dialogue: 0,0:00:42.00,0:00:46.00,Default,,0000,0000,0000,,respiratory secretions, cerebral spinal fluid,\Nurine, or some other body fluid.
Dialogue: 0,0:00:46.00,0:00:51.00,Default,,0000,0000,0000,,If the antigen is present in the sample, it\Nwill bind to the fixed antibodies.
Dialogue: 0,0:00:51.00,0:00:55.00,Default,,0000,0000,0000,,In this example, the green shape represents\Nthe antigen of interest and the other shapes
Dialogue: 0,0:00:55.00,0:00:57.00,Default,,0000,0000,0000,,represent other molecules in the sample.
Dialogue: 0,0:00:57.00,0:01:03.00,Default,,0000,0000,0000,,However, note that only the specific, or green,\Nantigen and none of the irrelevant molecules,
Dialogue: 0,0:01:03.00,0:01:05.00,Default,,0000,0000,0000,,bind to the antibody-coated wells.
Dialogue: 0,0:01:05.00,0:01:08.00,Default,,0000,0000,0000,,This accounts for the specificity of the test.
Dialogue: 0,0:01:08.00,0:01:12.00,Default,,0000,0000,0000,,The wells are then washed out to remove any\Nof the unattached molecules leaving the antigen
Dialogue: 0,0:01:12.00,0:01:15.00,Default,,0000,0000,0000,,of interest stuck to the wells.
Dialogue: 0,0:01:15.00,0:01:20.00,Default,,0000,0000,0000,,Now a second antibody, directed against another\Nepitope on the target antigen is added.
Dialogue: 0,0:01:20.00,0:01:25.00,Default,,0000,0000,0000,,These antibodies are conjugated covalently\Nto an enzyme indicated by the yellow circle
Dialogue: 0,0:01:25.00,0:01:28.00,Default,,0000,0000,0000,,at the FC portion of the second antibody.
Dialogue: 0,0:01:28.00,0:01:32.00,Default,,0000,0000,0000,,They bind to the antigen that's fixed in\Nthe well and this provides a second level
Dialogue: 0,0:01:32.00,0:01:34.00,Default,,0000,0000,0000,,of specificity for the assay.
Dialogue: 0,0:01:34.00,0:01:40.00,Default,,0000,0000,0000,,The wells are washed again to remove any unbound\Nantibodies and in the final step, a solution
Dialogue: 0,0:01:40.00,0:01:45.00,Default,,0000,0000,0000,,of a colorgenic enzyme substrate is added.
Dialogue: 0,0:01:45.00,0:01:49.00,Default,,0000,0000,0000,,The interaction of the substrate and the captured\Nenzyme generates visible color in the
Dialogue: 0,0:01:49.00,0:01:51.00,Default,,0000,0000,0000,,solution.
Dialogue: 0,0:01:51.00,0:01:56.00,Default,,0000,0000,0000,,At the macroscopic level, the development\Nof color indicates those samples that have
Dialogue: 0,0:01:56.00,0:01:59.00,Default,,0000,0000,0000,,second antibody bound to the target antigen\Nin the wells.
Dialogue: 0,0:01:59.00,0:02:03.00,Default,,0000,0000,0000,,Thus, the wells that change color are the\Nones that contain the antigen of interest,
Dialogue: 0,0:02:03.00,0:02:06.00,Default,,0000,0000,0000,,in other words, the positive results.