Figure 5. B and T Lymphocytes Are Important for pIB1⁻ Colonization in the MLN.

BALB/c or Rag1^−/− mice were intragastrically inoculated with 2 × 10⁹ WT IP2666 or IP2666 pIB1⁻.

(A) Size and weight of MLN from BALB/c or Rag1^−/− mice that were either uninfected or infected with WT IP2666 or IP2666 pIB1⁻ were measured.

(B) and (C) Colonization of the MLN or luminal content of the ileum 4 d post-intragastric inoculation of BALB/c or isogenic Rag1^−/− mice was determined. Each square indicates the cfu from one mouse calculated as log cfu/MLN (B) or the log cfu/g of luminal content of the ileum (C); bars represent the geometric mean. Each experiment was performed with two to three mice and repeated three times. Asterisks (*) and black circles (•) indicate statistically significant differences between the number of pIB1⁻ recovered from BALB/c mice versus Rag1^−/−, calculated by the t test (*p < 0.05) or by Mann-Whitney (•U < 0.05), respectively.