FIG 1.

OmpC–2W1S-specific CD4⁺ T cells remain elevated throughout persistent Salmonella infection and are required to control bacterial burden. (A and B) Representative flow cytometry plots are shown for I-A^b:2W1S tetramer staining for naive T cells and for T cells 17 days postinfection. (A) Spleen and (B) shows liver 2W1S-specific T cells. Numbers are the percentage of cells in each gate. (C) Total Salmonella-specific CD4⁺ T cells (2W1S:I-A^b+) were enumerated from each organ and are shown at the indicated times postinfection. (D) Mice chronically infected with S. Typhimurium for 44 days were antibody depleted of CD4⁺ T cells for 12 days before bacterial burdens were assessed. Bacterial burdens were determined in each organ after CD4⁺ T-cell depletion. Statistical differences were determined using two-way analysis of variance (ANOVA) and a Sidak’s multiple-comparison test. *, P < 0.05; **, P < 0.01. Representative of 2 independent experiments for time course and 4 independent experiments for depletion.