Immunofluorescence
The immunofluorescence (also immunofluorescence ; abbreviation IF ) is a biochemical and medical analysis method . Here, antigens by antibodies to which a fluorochrome is bound (fluorescent dye) labeled and thus made visible.
application
Immunofluorescence is widely used in medical diagnostics, especially in the context of immunohistochemistry .
A distinction is made between two different approaches:
- In direct immunofluorescence (DIF), cell components can e.g. B. can be detected from the tissue of a patient by applying antibodies to the previously prepared tissue, which react specifically (specifically) with the target structure. Since a fluorescent antibody is bound to these antigens, the structures can then be made visible under an immunofluorescence microscope. In this way, among other things, tumor tissue can be examined for certain properties. The DIF is used in particular for the representation of in vivo bound autoantibodies . a. Use in the differential diagnosis of dermatoses such as B. bullous pemphigoid or cutaneous leukocytoclastic vasculitis .
- In the indirect immunofluorescence whether present in the serum of patients antibodies directed against him shall be investigated. These are therefore called autoantibodies. To do this, a substrate is first required. This can be a tissue (e.g. liver, kidney, stomach) or individual cells (e.g. HEp2 cells, granulocytes). The substrate does not come from the patient, but z. B. from rodents or a cell culture. In the first step, the patient's serum is placed on the substrate and washed down after an incubation period so that only bound antibodies remain on the substrate. In the second step, a fluorochrome-labeled antibody that binds to human antibodies is applied to the substrate. If antibodies have bound to the substrate in the first step, the second antibody now binds to them. The antibodies can be detected using a fluorescence microscope. The result is a fluorescence pattern that allows conclusions to be drawn about the specificity of the autoantibodies. A homogeneous staining of the nucleus of an HEp2 cell indicates an antibody that reacts with an antigen homogeneously distributed in the nucleus. This is e.g. B. the case with antibodies against DNA.
literature
- Harald Renz (Ed.): Practical laboratory diagnostics . A textbook on laboratory medicine, clinical chemistry and hematology. de Gruyter, 2009, ISBN 978-3-11-019576-7 , p. 531 ff . ( online ).
- U. Sack u. a., (European Autoimmunity Standardization Initiative): Autoantibody detection using indirect immunofluorescence on HEp-2 cells . In: Annals of the New York Academy of Sciences . 1173, September 2009, pp. 166-173. doi : 10.1111 / j.1749-6632.2009.04735.x . PMID 19758146 .
Individual evidence
- ↑ Spektrum.de , Lexicon of Neuroscience "Immunofluorescence" . Last visited on 2017-02-27.