Figure 4.

CD11c⁺ XCR1⁺ cells are strictly required for medLN CD8⁺ T_LN reactivation, but conventional APCs are dispensable for lung CD8⁺ T_RM reactivation. (A) P14⁺ immune chimeras were generated in various genetic hosts as shown. For DTR mice, DT was administered i.t. 1 d before 2° infection to deplete DTR-expressing cells; for αGR-1 depletion, 200 μg αGR-1 (RB6-9C5) was administered i.p. daily starting the day before 2° rechallenge. For LCMV rechallenge experiments, flu-immunized mice were 2° infected with Armstrong strain of LCMV i.n. or LCMV-GFP. (B–D) Quantification of the frequency of Nur77-GFP⁺ P14⁺ T_LN cells in the medLN (B) and P14⁺ T_RM cells in the lung (C) at 48 h after 2° PR8-gp33 infection (B and C) or 48 h after 2° LCMV infection (D). Data shown are a collection of two or more independent experiments (n = 3–5 mice/group). (E and F) P14⁺ immune chimeras were rechallenged i.n. with LCMV-ZsGreen (E), and the colocalizations of ZsGreen signal with various immune cells in the medLN was quantified by Imaris (F). Top scale bars indicate 150 µm, and bottom scale bars indicate 20 µm. Data are expressed as mean ± SEM. Statistical analysis was performed using Student’s t test (two tailed) comparing immunized C57BL/6 to various treatment groups. ****, P < 0.0001.