Cross reactivity
In immunology, cross-reactivity is understood as the binding of an antibody to two different antigens , which, however, have an identical or very similar binding site ( epitope ) to which the antibody can bind. Since an antigen with a large number of epitopes is always used in the production of immune sera for use in serological test procedures, the immune serum always contains a mixture of different antibodies. When these immune sera are used in serological test procedures, these antibodies react not only against the original antigen (e.g. a certain pathogen A) but also against antigens of other origin (e.g. pathogen B), which leads to a false positive test result for the pathogen A leads. Cross-reactivity is therefore one of the reasons for a low specificity of a serological test.
Cross-reactivity is often found in very similar and taxonomically related bacteria or viruses . Due to an existing cross reaction within a pathogen species, so-called serotypes can often be defined and differentiated. These are then species with a uniform cross-reactivity to a specific antibody or immune serum.
A cross-reaction can also occur in a natural infection if antibodies directed against the pathogen cross-react with surface structures of the infected host. This cross-reaction can result in its own clinical pictures or the cross-reaction becomes a pathogenicity mechanism of the pathogen. This is the case , for example, with the molecular mimicry of Trypanosoma cruzi .
In pathological diagnostics, the cross-reactivity of antibodies used for immunohistochemical examinations can lead to diagnostic misinterpretations.
swell
- Ivan M. Roitt et al .: Short Textbook of Immunology . 2nd edition, Stuttgart, New York 1991 ISBN 3137021022 p. 82
Individual evidence
- ^ Franke et al .: Unexpected immunoreactivities of intermediate filament antibodies in human brain and brain tumors. In: Am J Pathol , 1991; 139 (1): 67-79, PMID 1713022 .