In vivo trafficking of adoptively transferred WT and T-bet^–/– antigen-specific T cells activated under Th1-polarizing conditions. (A-B) Flow cytometric analysis of WT (DO11.10) and T-bet^–/– (DO11.10 × T-bet^–/–) CD4⁺ T cells. Percentages of cells positive for CD4 and the clonotypic antibody KJ1-26 are indicated in various secondary lymphoid organs and in inflamed peritoneum (ILN indicates inguinal lymph nodes; MLN, mesenteric lymph nodes; and PL, peritoneal lavage). (C) Cell counts of secondary lymphoid organs and peritoneal lavage from BALB/c mice adoptively transferred with DO11.10 (WT) and DO11.10 × T-bet^–/– (T-bet^–/–) CD4⁺ T cells (mean ± SEM, *P < .001) activated with OVA peptide and mitomycin C–treated syngeneic splenocytes. □ indicates WT; ▪, T-bet^–/–.