Figure 1.

Immunization and challenge. Six-week-old male C57BL/6 and CD8 knockout mice were orally immunized with 10¹¹ WR201 and eight weeks later challenged with 10⁴ B. melitensis 16M. Data points represent mean CFU per organ (limit of detection = 2) for 4-5 mice (first three time points) and 10 mice (56-day time point) except where noted. The figure shows naive CD8 knockout mice (circles), naive C57BL/6 mice (triangles), immune CD8 knockout mice (squares), and immune C57BL/6 mice (diamonds). In no case did mice of the same immunization status have significantly different CFU levels at a given time point in a given organ.