Antigen presentation by nhAPCs alone alters CD8⁺ T-cell protective capacity but not lytic activity or secondary responses. B6→B6 and K^b−/−→B6 chimeras were immunized with 10⁷ pfu of rHuAd5-SIINFEKL-Luc intramuscularly. (A) In vivo lytic activity of SIINFEKL-specific CD8⁺ T cells at 42 days after immunization. SIINFEKL- and KAVYNFATM-pulsed Thy1.1⁺ splenocytes were labeled with a low concentration (0.5μM) and high concentration (5μM) of CFSE, mixed at a 1:1 ratio and adoptively transferred into immunized mice. Spleens and DLNs were removed 4 hours later. Data shown are gated on Thy1.1⁺ cells. The specific killing in each histogram represents the mean percentage (± SEM) for 5 mice. (B) Secondary expansion of SIINFEKL-specific CD8⁺ T cells after rVV challenge. Chimeras that were immunized 42 days previously with rHuAd5-SIINFEKL-Luc were challenged intraperitoneally with 10⁷ pfu of rVV-ESOVA. SIINFEKL-specific CD8⁺ T cells were measured using tetramer staining 7 days after challenge. Data represent the mean (± SEM) for 10 mice per group. Cells measured from blood, spleen, and peritoneal cavity lavage (PCL) are shown. (C) Tumor growth after B16M05 challenge. Chimeras that were immunized 20 days previously with 10⁷ pfu of rHuAd5-SIINFEKL-Luc or a control virus (rHuAd5-βgal) were challenged intradermally with 10⁶ B16M05 tumor cells, and tumor size was monitored daily. Data represent the mean tumor volume (± SEM) for 5 mice per group. (D) Virus titers in the spleen after LCMV-WE challenge. Chimeras that were immunized intramuscularly 24 days previously with 10⁸ pfu of rHuAd5-GP33-ER (Ad-GP33) or rHuAd5-βgal (Ad-βgal) were challenged intravenously with 200 pfu of LCMV-WE. Spleens were harvested 3 days after challenge. (E) Virus titers in the lung after influenza virus challenge. Chimeras that were immunized intranasally 30 days previously with 5 × 10⁷ pfu of rHuAd5-NP (Ad-NP) or rHuAd5-βgal (Ad-βgal) were challenged intranasally with 10⁵ pfu of mouse-adapted influenza A virus. Lungs were harvested 5 days after challenge. For data in panels D and E, each point represents a single mouse. *P < .05, ***P < .001.