Immunogold scanning electron microscopy applied to the study of Langerhans cells immunophenotype.

An immunogold technique in scanning electron microscopy was applied to the detection of Langerhans cell surface CD1a antigen in a heterogeneous human epidermal cell suspension. Scanning electron microscopy investigations performed in the secondary electron imaging mode and in the backscattered electron imaging mode allowed to define Langerhans cell surface morphology and the labeling degree, respectively. In particular, the backscattered electron imaging mode of the scanning electron microscope appeared very useful in identifying colloidal gold particles and, as a result, made it possible to make total counts of the labeled surface antigenic sites. Finally, the combination of secondary electron and backscattered electron signals generated mixed images with the Langerhans cell surface morphology well recognizable together with distinct gold particles. The immunogold labeling in scanning electron microscopy here described represents a highly sensitive method and yields a new improvement in the study of Langerhans cells immunophenotype.