Differential expansion of antigen-specific CD8⁺ T cells in immunized YOD1-C160S mice on viral infections. (A) A schematic of in vivo experiments is shown. Control and YOD1-C160S mice, which received OT-I cells, were immunized subcutaneously with 200 μg of Ova in IFA. The mice were challenged with a recombinant γ-herpes virus (MHV-68-M2-SIINFEKL) and analyses were performed 7 days after infection, respectively. In some experiments (G-J) OT-I cells recipient mice were infected with MHV-68-M2-SIINFEKL or influenza A virus (WSN-SIINFEKL) and analyses were performed 7 or 10 days after infection, respectively. (B-F) Control and YOD1-C160S mice were transferred with 5 × 10⁵ of OT-I cells and immunized with 200μg of Ova in IFA. Seven days after immunization frequencies of K^b−SIINFEKL-Tet⁺ cells were measured in peripheral blood and mice were then infected intranasally with 2 × 10⁴ PFU of recombinant MHV-68-M2-SIINFEKL virus. At 7 days after immunization, the activation status, frequencies, and numbers of antigen specific cells were measured in the draining mediastinal LN and viral burden was measured in the extracted lung tissues. Representative FACS plots (B) and bar diagrams (C) show the frequencies of K^b-SIINFEKL-Tet⁺ cells in the peripheral blood of immunized mice before viral infection. Representative FACS plots (D) and bar diagram (E) show the frequencies of K^b-SIINFEKL-Tet⁺ and ORF8-Tet⁺ CD8⁺ T cells in the mediastinal LN of mice 7 days after infection. (F) Viral titers in lung homogenates of 2 groups of mice are shown. (G-H) Five × 10⁵ naive OT-I cells were transferred intraperitoneally into control and YOD1-C160S mice 1 day before infection with 5 × 10⁵ PFU of MHV-68-M2-SIINFEKL virus. Representative FACS plots (G) and bar diagram (H) show the frequencies of antigen-specific cells in spleens of infected mice 7 days after infection. (I-J) Untransferred or OT I cells (5 × 10³) recipient mice control and YOD1-C160S mice were infected with 100 PFU of WSN-SIINFEKL intranasally and the expansion of K^b-SIINFEKL-Tet⁺ cells were measured 10 days after infection in mediastinal LNs. Representative FACS plots (I) and bar diagrams (J) show the frequencies of Tet⁺ cells. Experiments were repeated twice with similar results.