Fig. 2
In vivo infection of mice. Six-week-old C57BL/6 mice were intravenously injected with either freshly collected X4550(pYA3334), X4550(pYA3334-P-SspH2) or X4550(pYA3334-P-SspH2-EscI), 1× 106 cfu/mouse. The uninfected mice were used as control. Several weeks later, the bacterial counts (a) in mouse spleens and livers, the activation of splenic T lymphocyte subsets (b), the ratio of splenic CD4+/CD8+ T cells (c) were analyzed. Five mice were used in each treatment. One-week post immunization, the immunized mice were challenged intraperitoneally with wild-type Salmonella strain D6. The bacterial colonization (d) in mouse spleens and livers challenged with 1× 105 cfu/mouse and the survival of mice challenged with 5 × 106 cfu/mouse were counted (e) for immune protection assay. Nine mice were used for each treatment