Figure 1.

CD40 co-stimulation increases CTL responses to rMVA encoded antigens but not to a protein antigen. C57BL/6 mice were immunized with rMVA, rMVA + anti-CD40 mAb, or OVA protein + anti-CD40 mAb. B8- and OVA-specific CD8 T cells were visualized by MHC class I dextramer staining. (A) Density plots illustrate the frequency of B8- and OVA-specific CTL in the blood on day 7 (gated on CD8⁺ PBL). Numbers indicate the percentage of CD8⁺ dextramer⁺ T cells among PBL. A kinetic analysis of B8- and OVA-specific CTLs is shown in (B). CTL responses to B8 and OVA were drastically enhanced by co-injection of rMVA and anti-CD40 mAb. Note, that no detectable CTL response was generated after immunization with OVA protein and anti-CD40 antibody. (C) Similar to the above described experiment, CBA/J (H-2k) mice were immunized with rMVA-GP encoding the glycoprotein of Zaire Ebola virus ± anti-CD40 mAb. The GP-specific CD8 T cell response was measured 7 days later by intracellular cytokine staining. Shown is the mean percentage ± SEM of IFN-γ⁺ GP-specific CD8 T cells in the spleen. Data are representative of four mice per group.