The Mouse IgG1, mAb MOPC-21 immunoglobulin is useful as an isotype control for several applications: Western blotting, immunoprecipitation, immunohistochemistry, immunofluorescence and immunofluorescent staining (surface or intracellular) for flow cytometric analysis. This isotype control is low endotoxin and is therefore suitable for functional studies. Ultra low endotoxin for for example highly sensitive assays or in vivo studies is also available (Cat. # HI5001).