FIG. 2.

Deposition of complement components C3, C6, and C5b-9 on the surface of borreliae. Activated complement components deposited on the surface of serum-resistant B. spielmanii isolates TIsar2 and TIsar3, serum-resistant B. burgdorferi LW2, and serum-sensitive B. garinii isolate G1, detected by indirect immunofluorescence microscopy. Spirochetes were incubated with either 25% NHS or hiNHS for 30 min at 37°C with gentle agitation, and bound C3, C6, and C5b-9 were analyzed with specific antibodies against each component and appropriate Alexa Fluor 488-conjugated secondary antibodies. For visualization of the spirochetes in a given microscopic field, the DNA-binding dye DAPI was used. The spirochetes were observed at a magnification of ×100. The data were recorded via a DS-5Mc charge-coupled-device camera (Nikon) mounted on an Olympus CX40 fluorescence microscope. Panels shown are representative of at least 20 microscope fields.