Figure 4.

4-1BB is not required on antigen-reactive CD8 T cells responding during VACV infection. (a-b) 5 × 10⁴ naive WT or 4-1BB-/- OT-I CD8 T cells were adoptively transferred into congenic B6 mice. One day later, mice were infected i.p. with recombinant VACV expressing full-length OVA (VACV-OVA; a: 2 × 10³ PFU/mouse, or b-c: 2 × 10⁵ PFU/mouse). 45 days after infection, splenocytes were stimulated with OVA (SINFEKL) peptide. Total numbers of donor CD8⁺Vα2⁺Vβ5⁺ cells (a, b) and CD8⁺IFN- ⁺ cells (c) were enumerated. (c) Representative plots of IFN- and TNF, gating on CD8⁺Vα⁺Vβ⁺ cells. Percentages positive are indicated. Data represent mean value ± sem from n=4 to 6 mice. Similar results were reproduced in two separate experiments.