Antigen presentation is dramatically reduced and memory CD8⁺ T-cell phenotype is altered when nonhematopoietic cells are the only functional APCs, but kinetics and magnitude of the CD8⁺ T-cell response are similar. B6→B6 and K^b−/−→B6 chimeras were immunized with 10⁷ pfu of rHuAd5-SIINFEKL-Luc intramuscularly. (A) At various days after immunization, mice were injected intravenously with 5 × 10⁵ CFSE-labeled cells harvested from the LNs of Thy1.1⁺ OT-I mice. The DLNs were harvested 4 days after transfer and CFSE dilution was measured in the Thy1.1⁺ population. Total number of proliferated (CFSE^lo) cells in the DLNs is shown. Each data point represents the mean (± SEM) from a total of 4 mice. (B-C) Frequency of SIINFEKL-specific CD8⁺ T cells was measured by tetramer staining of peripheral blood at day 8 (B) or at various time points (C) after immunization. Data points represent a total of 5 to 12 mice (± SEM). (D) Expression of various phenotypic markers on tetramer-positive CD8⁺ T cells in the spleen at 42 days after immunization. (E) The frequency of T_EFF (CD127⁻CD62L⁻), T_EM (CD127⁺CD62L⁻), and T_CM (CD127⁺CD62L⁺) within the tetramer-positive population at day 42. Data in panels D and E represent the mean (± SEM) for 4 mice and are reflective of 2 experiments with similar results (n = 4 for each experiment). *P < .05, **P < .01.