The X40 antibody (IgG1, kappa) is suitable for use as an isotype-matched control antibody in several applications to estimate the degree of non-specific binding by an antigen-specific antibody. Ideally, the isotype control should have the same subclass of heavy chain (IgA, IgD, IgE, IgG, or IgM) and light chain (kappa or lambda) as the specific antibody being used. If a conjugated antibody is used, an isotype control conjugated to the same molecule (e.g. fluorochrome) should be chosen. The use of an appropriate isotype control helps confirm the specificity of the antigen-specific antibody and indicates non-specific binding that may result from binding to Fc receptors or other cell components.

This antibody clone has been verified for use as an isotype control antibody for assessing non-specific binding to cells in applications such as flow cytometry and immunofluorescence microscopy applications (surface and intracellular staining).