In competitive ELISA, unlabeled antibody is incubated in the presence of its antigen. Then these bound antibody/antigen complexes are then added to an antigen coated well. After washing, unbound antibodies are removed. The more analytes in the sample, the less antibodies will be able to bind to antigens in the well. The signal is then detected using labeled secondary antibodies and the decrease in signal is compared to a control. The major advantage of a competitive ELISA is the ability to use crude or impure samples and still selectively bind any antigen that may be present.
Immunofluorescence is a technique to visualize a specific protein or antigen in cells or tissue sections by binding a specific antibody chemically conjugated with a fluorescent dye. We use the indirect immunofluorescence staining to perform cells fixed on slides and examine under a fluorescence microscope.
Cell culture is the process by which cells are grown under controlled conditions. This video show you how to culture attached cells from cell thrawing, maintain, to cell freezing.