Reactivity of monoclonal antibodies EG1 and EG2 with eosinophils and their granule proteins

Abstract

Use of the murine monoclonal antibodies EG1 and EG2 has been based on the assumption that EG2 recognizes activated eosinophils. We examined the reactivity of EG1 and EG2 with eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), and stimulated and nonstimulated eosinophils from normal donors. By radioimmunoassay, EG1 recognized only ECP, whereas EG2 recognized both ECP and EDN. By Western blot, EG1 reacted with ECP, EG2 reacted with both ECP and EDN, but EG2 could not distinguish between lysates of stimulated and nonstimulated eosinophils. By immunofluorescence, EG1 and EG2 at 20 g/mL stained 95-100% of nonstimulated eosinophils, regardless of fixative; EG1 and EG2 at 0.1 g/mL stained 61-90% of acetone-and paraformaldehyde-fixed and only 5-21% of methanol-fixed nonstimulated eosinophils. Thus, the reactivity of EG1 and EG2 with eosinophils depends on the method of fixation and antibody concentration; and EG2, in contrast to previous reports, cannot reliably discriminate between resting and activated eosinophils. J. Leukoc. Biol. 66: 447-454; 1999.

Kinetics of Bone Marrow Eosinophilopoiesis and Associated Cytokines after Allergen Inhalation

“…All of these changes were confirmed in this study, although markers for eosinophil activation may not be ideal (25). Contrasting these two groups allows for a useful clinical model of increased eosinophilic airway responses and associated airway functional changes.…”

Tissue eosinophilia in acute and chronic atopic dermatitis: a morphometric approach using quantitative image analysis of immunostaining

“…Accordingly, the participation of eosinophils in allergic inflammation is complex, but extracellular tissue deposition of reactive oxygen species and EGPs is their most important local effector function and the result of complete activation with cytolysis 2,4 , 6–8 . It was recently shown that EG2 immunostaining cannot reliably distinguish between activated and resting eosinophils 29,30 . As a consequence, neither the total number nor the number of EG2‐positive eosinophils, but instead the frequency, amount and distribution of extracellular EGP deposition can be considered to be crucial for the evaluation of tissue eosinophilia, at least with respect to activation.…”

Recent considerations in the use of recombinant interferon gamma for biological therapy of atopic dermatitis

“…EG2 is a murine monoclonal antibody, and marker of activated eosinophils as it recognizes eosinophil cationic protein [40]. Epidermal staining of HLA-DR was also seen.…”