Muscle-directed AAV-OVA gene transfer in C57BL/6 mice. (A) Systemic OVA levels as a function of time after intramuscular injection of AAV-CMV-OVA vector (1 × 10¹² vg/animal) in wild-type (♦) or CD8-deficient (▪) C57BL/6 mice (4/group). (B) Analysis of muscle sections (day 21 after gene transfer). Panels in left column are from wild-type mice; panels in right column are from CD8-deficient mice. Shown are immunofluorescence stain for OVA expression (top row, green stain, FITC label), hematoxylin and eosin stain (middle row), and immunofluorescence stain for CD8 (green stain, FITC label, bottom row). (C-F) In vitro assay for cytotoxic T-lymphocyte responses to OVA in wild-type C57BL/6 mice. Shown are percentage lysis of MHC I-compatible, OVA-expressing E.G7-OVA target cells (ova; ▪) and EL-4 mock targets (mock; ♦) as a function of effector-target cell ratio. (C,E) Effector cells were splenocytes from mice 10 or 30 days after intramuscular administration of 1 × 10¹² vg AAV-CMV-OVA. (D) Effector cells were LN cells (draining, D-LN, or nondraining, ND-LN) from mice 10 days after intramuscular administration of 1 × 10¹² vg AAV-CMV-OVA. (F-G) Effector cells were splenocytes (F) or LN cells (G) from mice 10 days after intramuscular administration of AAV-C5/12-OVA vector.