FIG. 2.

Reduced degradation of B. burgdorferi by MyD88^−/− macrophages. Adherent macrophages were exposed to spirochetes at a 1:10 ratio of macrophages to spirochetes, dipped in ddH₂O to eliminate extracellular spirochetes, and incubated in fresh medium until fixation at 0, 20, 60, 120, and 180 min as described in Materials and Methods. Monolayers were then fixed and double labeled for spirochetes (red) and the lysosomal marker LAMP-1 (green). Images were recorded on a Zeiss LSM 510 confocal imaging system using a 63× objective. (A) WT macrophages at 2 h. (B) MyD88^−/− macrophages at 2 h. (C) Percentages of elongated B. burgdorferi spirochetes associated with macrophages as a function of time. Note the protracted presence of elongated spirochetes in MyD88^−/− macrophages. The results are representative of two experiments.