FIG. 2.

Comparison of the effects of antibody on the internalization of R. conorii into mouse endothelial cells (A) and macrophages (B). Host cells which were preincubated with normal mouse serum (open bars) had many fewer viable internalized rickettsiae than cells which were not preincubated with normal serum (filled bars). Greater quantities of viable internalized rickettsiae that had been treated with polyclonal antibody or monoclonal anti-OmpA or anti-OmpB were present in both endothelial cells and macrophages at 3 h after infection than those of untreated or normal serum-treated or Fab antibody-treated rickettsiae (P < 0.001). ND, no rickettsiae detected. These results represent the average of three separate experiments.