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Monoclonal antibody EG2 reactivity cannot be used as an immunohistochemical activation marker for eosinophils
Author(s) -
Jahnsen Frode L.,
Brandtzaeg Per
Publication year - 1995
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.57.3.513
Subject(s) - immunohistochemistry , eosinophil cationic protein , monoclonal antibody , biology , epitope , eosinophil , antibody , immunocytochemistry , blot , microbiology and biotechnology , secretion , immunology , biochemistry , endocrinology , gene , asthma
To the Editor : Rosenberg and Tiffany recently described [1] that the presumed “activation‐specific” antibody EG2 recognized only one (the smallest) of three glycosylated forms (18 kDa, 20 kDa, and 22 kDa) of eosinophil cationic protein (ECP). On the basis of this finding they proposed two alternative ways to explain how the epitope for EG2 was accessible only in activated eosinophils. They suggested that deglycosylation of ECP could occur in conjunction with activation and secretion; this was unlikely though because the 18‐kDa form constitutes a substantial fraction of ECP (by Western blotting) even in resting eosinophils [1, 2]. Then they speculated that the 18‐kDa form of ECP might be functionally undetectable prior to secretion. 1 We have recently shown, however, that cellular EG2 reactivity does not reliably discriminate between resting and activated eosinophils by immunocytochemistry and immunohistochemistry [3]. All blood eosinophils from healthy individuals were strongly EG2‐positive when fixed in formalin, and a substantial fraction reacted in the unfixed or acetone‐fixed state as well, although with variable intensity. Even after maximum activation (phorbol ester) EG2 could not discriminate eosinophils from their resting counterparts [4].