Enhanced biological cathodoluminescence

We have combined the specificity of antibody labeling, the power of fluorescence detection, and the resolution of scanning electron microscopy (SEM) to identify antigenic sites on nanometer-scale features of mammalian cells. Cathodoluminescence (CL) detection in SEM was used to locate fluorophores bound to antibodies specific for cell surface epitopes. Sample preparation and instrument setup were optimized to yield the maximum luminescence compatible with a high definition secondary electron image. Separable CL component distances of less than 300 nm have been calculated. Antibody-specific fluorophores are associated with unique morphological features on a human dendritic cell. This technology provides a tool to identify the relationship between cell surface structures and receptor-ligand binding or other antigen-defined physiological states.