ab91537 reacts with an undefined epitope on a plant pathogen. No reactivity with cell surface antigens on Human, Porcine, Mouse or Rat. It can be used as a negative control for immunofluorescence staining (e.g. Flow Cytometry) when using Mouse monoclonal antibodies to Human cell surface antigens of isotype IgG1. ab91537 enables an estimation of non specific binding of Mouse monoclonal antibodies to cell surface components in peripheral blood and tissue. It is suitable for whole blood, Ficoll separated preparations, frozen and paraffin embedded sections.