FIG. 4.

Negative staining combined with immunoelectron microscopy of C. pneumoniae. Pellets from culture supernatants of THP-1 cells infected with C. pneumoniae isolated from a patient with AD and cultured for 7 days were absorbed onto carbon-coated copper electron microscopy grids. Grids were exposed to the primary antibodies, incubated, and subsequently incubated with secondary antimouse antibody conjugated to 5 nm colloidal gold particles. (A) Immunogold particles are bound to the anti-SAF-labeled bacterium, examples of which are depicted with arrows. (B) An area of a bacterium apparently rich in OMP (arrow) is exposed and labeled with gold particles. (C) A bacterium reacted with anti-LPS demonstrates heavy labeling with many gold particles bound to its surface. Bars = 0.75 μm (A) and 0.5 μm (B and C).