Mice immunized with Ad5-mOva delivered in collagen versus PBS have increased protection against Lm-OVA. (A) B6 mice were immunized subcutaneously on the flank with 10⁶ pfu Ad5-mOva in PBS or 30 mg/mL collagen. Fourteen days later, mice were challenged intravenously with 10⁵actA⁻ Lm-OVA, an attenuated strain. Twenty-four hours later, spleens were harvested and CFUs/spleen were measured as described in “Methods.” Data are from 3 experiments of 4 to 5 mice per group. Wilcoxon sign-rank 2-tailed P = .002. (B) Mice were treated as in panel A, but were challenged with virulent Lm-OVA. Splenic CFU was assessed 72 hours later. LOD indicates limit of detection.