Methods of Antigen Retrieval and Application of ImmunohistochemistryMalak Taher Almusallam2160002490Methods of Antigen Retrieval and Application of ImmunohistochemistryIntroduction:In 1893, Ferdinand Blum discovered formaldehyde as a tissue fixative which still used until our time. Although the presence of fixatives other than formalin, there is no one takes the place of formalin. The reason for that is formalin used for a long time as a standard tissue fixative. The contemporary evolution of immunohistochemistry (IHC) makes a huge advance for the functional and analytical morphology in the histopathology. However, prevalent of immunohistochemical application led to the critical criticism about the use of formalin fixation due to the adverse and significant effect on many antigens to be investigated. This a big problem for histopathologists during applying of immunohistochemical stains for tissue fixed in formalin and embedded in paraffin.
Therefore, many technical evolutions were done to make the immunohistochemical methods more efficient. Many developments were done on fixation methods to preserve some types of antigens. However, they failed to find perfect fixative. Moreover, modified types of fixative do not ideally preserve morphology as formalin do. So, it changed the criteria for histopathological diagnosis. The main reason for the development of antigen retrieval is to preserve immunochemistry and morphology by formalin. The struggles were whether the antigens changed reversibly or irreversibly by formalin fixation.
In 1940 Fraenkel and his colleagues performed a biochemical study for the reaction of formalin with protein, and they concluded that hydrolyzing the formalin-protein cross-linkages is restricted by specific chains of amino acid. This form a foundation stone that leads to antigen retrieval development. Therefore, antigen retrieval methods became efficient with more than two hundred antibodies ADDIN EN.CITE <EndNote><Cite><RecNum>3</RecNum><DisplayText>(Shi 1997)</DisplayText><record><rec-number>3</rec-number><foreign-keys><key app=”EN” db-id=”de9pfddfkvws5dew554pt9pefxwetvrfpwvd” timestamp=”1542035960″>3</key></foreign-keys><ref-type name=”Journal Article”>17</ref-type><contributors></contributors><titles></titles><dates></dates><urls></urls></record></Cite><Cite><Author>Shi</Author><Year>1997</Year><RecNum>4</RecNum><record><rec-number>4</rec-number><foreign-keys><key app=”EN” db-id=”de9pfddfkvws5dew554pt9pefxwetvrfpwvd” timestamp=”1542036033″>4</key></foreign-keys><ref-type name=”Journal Article”>17</ref-type><contributors><authors><author>Shi, S., Cote, R. J., & Taylor, C.
R. </author></authors></contributors><titles><title>Antigen Retrieval Immunohistochemistry?: Past , Present , and Future</title></titles><number>45(3), 327–343</number><dates><year>1997</year></dates><urls></urls></record></Cite></EndNote>(Shi 1997).Immunohistochemistry technique (IHC) and historical background:Immunohistochemistry uses a combination of the immunological, histological and biochemical methods to detect protein in a powerful and simple technique.
It gives helpful information as it detects the localization and distribution of specific cells components. Moreover, it detects cells antigens and haptens by applying the antibody-antigen binding principle. The binding of an antibody to the antigen can be detected in different methods such as enzymes to detect a reaction by forming a color. The immunohistochemical technique does not give quantitative information however it shows them visually to explain the data resulted from quantitative methods.
In the previous years, for animal diagnosis, there are only a limited number of antibodies due to the incompetence to regain the changes of proteins structure caused by formalin fixative. However, the presence of developed fixative that preserves the tissue antigenicity, but they were not in use as a formalin was the standard in fixation. 20 years ago, development of procedures to return the changes caused by fixation. In the beginning, detergents or chaotropic treatment or digestion by enzymes utilized. However, unrecognized epitopes by antibodies still high for tissue fixed in formalin.
Another method was derived at 1940 but not utilized in immunohistochemistry until fifty years later, which based on the increase the heat for sections treatment, therefore increasing the detection of antigens number by immunohistochemistry. Sometimes, to the combination of heat and enzyme digestion make immunohistochemical more efficient ADDIN EN.CITE <EndNote><Cite><Author>Ramos-Vara</Author><Year>2000</Year><RecNum>5</RecNum><DisplayText>(Ramos-Vara 2000)</DisplayText><record><rec-number>5</rec-number><foreign-keys><key app=”EN” db-id=”de9pfddfkvws5dew554pt9pefxwetvrfpwvd” timestamp=”1542041510″>5</key></foreign-keys><ref-type name=”Journal Article”>17</ref-type><contributors><authors><author>Ramos-Vara, J. A.
, & Beissenherz, M. E.</author></authors></contributors><titles><title>Optimization of immunohistochemical methods using two different antigen retrieval methods on formalin-fixed, paraffin-embedded tissues: Experience with 63 markers. </title><secondary-title>Journal of Veterinary Diagnostic Investigation</secondary-title></titles><periodical><full-title>Journal of Veterinary Diagnostic Investigation</full-title></periodical><number>12(4), 307–311.</number><dates><year>2000</year></dates><urls></urls></record></Cite></EndNote>(Ramos-Vara 2000).Antibody Immunohistochemical technique use monoclonal and polyclonal antibodies.References: ADDIN EN.
REFLIST Ramos-Vara, J. A., & Beissenherz, M.
E. (2000). “Optimization of immunohistochemical methods using two different antigen retrieval methods on formalin-fixed, paraffin-embedded tissues: Experience with 63 markers. .” Journal of Veterinary Diagnostic Investigation(12(4), 307–311.
).Shi, S., Cote, R.
J., & Taylor, C. R. (1997).
“Antigen Retrieval Immunohistochemistry?: Past , Present , and Future.” (45(3), 327–343).
