- Immunofluorescence
Immunofluorescence is the labeling of antibodies or
antigens with fluorescentdye s. This technique is often used to visualize the subcellular distribution ofbiomolecules of interest. Immunofluorescent-labelled tissue sections or cultures are studied using afluorescence microscope or byconfocal microscopy .Most commonly, immunofluorescence employs two sets of antibodies: a primary antibody is used against the antigen of interest; a subsequent, secondary, dye-coupled antibody is introduced that recognizes the primary antibody. In this fashion the researcher may create several primary antibodies that recognize various antigens, but, because they all share a common constant region, may be recognized by a single dye-coupled antibody. Typically this is done by using antibodies made in different species. For example, a researcher might create antibodies in a goat that recognize several antigens, and then employ dye-coupled rabbit antibodies that recognize the goat antibody constant region (denoted rabbit anti-goat). This allows re-use of the difficult-to-make dye-coupled antibodies in multiple experiments.
In some cases, it is advantageous to use primary antibodies directly labelled with a
fluorophore . This direct labelling decreases the number of steps in the staining procedure and, more importantly, often avoids cross-reactivity and high background problems.Fluorescent labelling can be performed in less than one hour with readily available labeling kits.As with most fluorescence techniques, a significant problem with immunofluorescence is
photobleaching . Loss of activity caused by photobleaching can be controlled by reducing the intensity or time-span of light exposure, by increasing the concentration of fluorophores, or by employing more robust fluorophores that are less prone to bleaching (e.g.Alexa Fluor s orDyLight Fluor s).Many uses of immunofluorescence have been outmoded by the development of
recombinant protein s containing fluorescent protein domains, e.g.green fluorescent protein (GFP). Use of such "tagged" proteins allows much better localization and less disruption of protein function.Protocol
Immunostaining protocol External links
* [http://www.ii.bham.ac.uk/clinicalimmunology/CISimagelibrary/ Images associated with autoimmune diseases] at
University of Birmingham
* [http://www.confocal-microscopy.org/Protocols%20-%20Immunofluorescence.htm Immunofluorescence protocol and confocal microscopy resources] at confocal-microscopy.org
* [http://www.bio.davidson.edu/COURSES/genomics/method/IMF.html Overview] atDavidson College
* [http://www.prosci-inc.com/Immunofluorescence-Protocol.html Immunofluorescence Staining Protocol]*
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