UBC Theses and Dissertations
An immunochemical and immunocytochemical study of the S-100b protein Boyes, Barry Edward
This thesis describes an immunochemical and immunocytochemical study of the bovine brain S-lOOb protein. The two major forms of the S-100 isoproteins (S-lOOa and S-lOOb) were purified to apparent homogeneity from bovine brain. A polyclonal rabbit antiserum to the S-lOOb protein was prepared. The antiserum was characterized by solid phase immunochemical methods. The S-lOOb derived antiserum displayed a high degree of specificity for S-lOOb, but also crossreacted with the purified S-lOOa protein. The characteristics of the immunochemical reactivity of the antiserum towards these two isoproteins suggests the antiserum has specificity for the 6-subunit of the S-100 proteins. An immunohistochemical analysis of the cellular localization of S-lOOb immunoreactivity was undertaken. In the adult rat brain only the astrocytes were S-lOOb immunoreactive. This conclusion is supported by the morphological characteristics of the immunolabelled cells, as well as the observed co-localization of the immunoreactivities for S-lOOb and the Glial Fibrillary Acidic protein (GFAP), the major protein of the astrocyte intermediate filaments. These two antigens were always found to coexist. The immunolabelling of rat brain astrocytes by the S-lOOb derived antiserum stained the entire cell, yielding more complete morphological detail than is possible with the GFAP immunohistochemistry, which only labels the filamentous glial processes. It is concluded that S-lOOb immunohistochemistry could be of general utility in the investigation of astrocyte morphology. The present results also determine that the as yet unknown biological function(s) of the S-100 proteins must be related to a property of astrocytes.
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