An increased number of CXCR3^−/− memory CD8⁺ T cells is observed in lymphoid and nonlymphoid organs. (A) Expression kinetics of CXCR3 on antigen-specific CD8⁺ T cells in peripheral blood at the indicated times after VV-OVA infection. Representative histograms gated on CD8⁺ T cells, CD44^mid, and CD62L^lo before infection and Kb-OVA₂₅₇–tetramer⁺ after infection. Numbers on the plot indicate the percentage positive for CXCR3. Black line: CXCR3; shaded: isotype control. (B) Naive splenic CXCR3^−/− (CD45.2⁺) and WT (CD45.1⁺CD45.2⁺) OT-I cells were mixed in a 1:1 ratio, and a total of 1 × 10⁴ cells were adoptively transferred into naive CD45.1⁺ mice. The next day, the recipient mice were i.v. infected with 2 × 10⁶ PFU VV-OVA. Flow plot shows representative mixed OT-I cells before transfer. (C) Representative plots gated on OT-I cells (CD45.2⁺) in the spleen at the indicated times after infection. Numbers on the plots indicate the percentage of WT (top) and CXCR3^−/− (bottom) OT-I cells in the total OT-I population. (D) Number of OT-I cells in the spleen after VV-OVA infection. Data are shown as mean ± SEM. (E) Number of OT-I cells in blood, liver, lung, spleen, and lymph nodes on day 7 (left) and day 225 (right) after infection. OT-I cells in blood are plotted per 1 × 10⁷ cells. Data are shown as mean ± SEM. *, P < 0.05. Data represent two (A) or three (B–E) independent experiments (n = 4–5 and 3–4 per time point, respectively).