The Mouse IgG1 isotype control antibody clone IS5-21F5 is specific for KLH (keyhole limpet hemocyanin). This protein is not expressed on human cells or cell lines. Therefore, the antibody clone IS5-21F5 can be used as a negative control, to distinguish specific from non-specific binding of mouse IgG1 fluorochrome-conjugated antibodies to human cells, for example via Fc receptors, or due to interactions of the fluorochrome with the cell surface.
Human PBLs were stained with Mouse IgG1 antibodies conjugated to FITC (A), PE (B), APC (C), VioBlue (D), VioGreen (E), PerCP (F) or APC-Vio770 (G) and analyzed by flow cytometry using the MACSQuant Analyzer. Cells stained with IgG1-Biotin (H) were stained with Anti-Biotin-APC in addition. Gates were set on viable lymphocytes.