Figure 5.

The rLCMV vectors target and activate DCs. (a) Flow cytometry of GFP expression in DCs (CD11c⁺), macrophages (F4/80⁺), T cells (CD3⁺) and B cells (CD19⁺) in Z/EG transgenic reporter mice 3 d after vaccination with rLCMV-Cre or rLCMV-OVA (control vector). Numbers in outlined areas indicate total number of fluorescent cells per spleen (mean ± s.e.m.); gates were set such that no positive cells were recorded for mice vaccinated with rLCMV-OVA. Data are representative of four Z/EG mice per group. (b) CD86 surface expression on CD11c⁺ DC populations from the mice in a, identified as GFP⁺ (pos.) or GFP⁻ (neg.) and stained with antibody to CD86 (α-CD86) or isotype-matched control antibody (Isotype). (c) GP33-specific CD8⁺ T cell frequencies in blood of ST33 mice vaccinated with rLCMV-Cre or rLCMV-OVA control vector, assessed by major histocompatibility complex class I (H-2D^b) tetramer staining on days 10 and 27 after vaccination (left), and GP33-specific recall responses in spleen after mice were challenged with VACC-G2 on day 28 of the experiment, assessed 6 d later by intracellular cytokine assay. Numbers in plots indicate percent tetramer-positive CD8⁺ T cells (left; top right quadrant) or percent IFN-γ⁺ CD8⁺ T cells (right; top left quadrant) or IFN-γ⁺TNF-α⁺ CD8⁺ T cells (right; top right quadrant). Data are from one representative of two similar experiments (mean ± s.d. of three to four mice per group).