Figure 1. A primed innate cell population provides protection against a challenge with recombinant vaccinia virus.

Six months after intraperitoneal (ip) inoculation with vaccinia virus (primed) or PBS (naïve), IgH^ko mice were treated with T cell-depleting or isotype control antibody mixtures and 10 days later were challenged with 2×10⁶ pfu rVV-luc intraperitoneally (ip). Isotype control or depleting monoclonal antibodies were administered ip every 2 weeks starting a week to ten days prior to viral challenge. (a) Flow cytometric plots of CD3 staining of peripheral blood cells from naïve control, naïve T-depleted, or primed T-depleted mice that fall within the lymphocyte gate are shown, including the percentage of total cells within the CD3⁺ gate at 1 week post-challenge. The TCRβ, TCRγδ, and CD8α staining profiles of the cells that fall within the CD3⁺ gate are also shown. (b) IVIS images of representative mice from the naïve control, naïve T cell-depleted, and primed T cell-depleted groups following the challenge with rVV-luc are shown. (c) The measurements of rVV-luc viral loads in each group over time are shown with relative viral loads based on the number of photons emitted normalized for a one minute exposure. The measurement for each individual mouse is plotted, and the center line indicates the mean with error bars representing the SEM. Statistical significance between T-depleted groups was assessed by t-tests using Mann-Whitney analysis and is indicated by the asterisk (p<0.05). Results are representative of 4 independent experiments.