Negative-Stain Immunoelectron-Microscopic Analysis of Small Macromolecules of Immunologic Significance

We have demonstrated that unlabeled antibodies or their antigen-reactive fragments, Fab and F(ab')2, can be readily visualized by negative-stain immunoelectron microscopy and can be quite useful as probes for detailed epitope mapping and structural analysis of relatively small macromolecules. In addition, information on segmental flexibility of the target molecules can be deduced as can information on the geometry and kinetics of immune complex formation in solution. The various target molecules used to illustrate these points include IgG, IgM, C-reactive protein, and complement receptor 1.