Colonization of intestinal and lymph tissues at day 1 and day 2 postinfection with 2 × 109 CFU of wild-type Y. pseudotuberculosis (filled diamonds), yopHEMOJ (open circles), or yopBHEMOJ (open triangles). Data from four to six mice from two experiments were pooled. Each symbol represents the log10 CFU/gram of tissue from one mouse colonized with the appropriate strain. All points were above the limit of detection of 10 CFU/gram of tissue. At day 1, colonization by yopHEMOJ and yopBHEMOJ was statistically different (**; P < 0.01) from that by the wild-type strain in the ileum, colon, and PP. At day 2, colonization by yopHEMOJ and yopBHEMOJ are statistically different from the wild-type strain (P < 0.01) in all tissues.