Histochemical and immunochemical analyses of skeletal muscle from DO11.10 TCR transgenic BALB/c mice. Muscle cross-sections were taken at day 10 (A-C,G-I,L,N) or day 30 (D-F,J,K,M,O) after intramuscular injection of AAV-CMV-OVA (1 × 10¹² vg/mouse) from injected legs (A-B,D-E,G-H,J,L-O) and contralateral noninjected legs (C,F,I,K). Panels A-F represent muscle sections stained with hematoxylin and eosin (HE); panels G-K represent dual immunofluorescence stain for OVA (red stain, TRITC label) and CD8 (green stain, FITC label). Sections of injected leg muscle were also stained for IFN-γ–expressing cells (panel L, day 10, and panel M, day 30). Dual antibody stain for CD4 (green stain, FITC label) and DO11.10 TCR (red stain, TRITC label) are shown in panels N-P. Panels N and O are vector-injected muscle, days 10 and 30, respectively. Dual positive cells are shown by arrows in panels N and P, and are abundant in panel O. Panel P shows CD4/TCR stain on lymphocytes from DO11.10 TCR transgenic BALB/c mice. Original magnifications × 100 (A-K), × 200 (L-O), and × 400 (P). (Q-S) Muscle sections from animals 30 days after AAV-CMV-GFP (1 × 10¹² vg/mouse) administration. GFP expression is shown for injected (Q) and contralateral noninjected (S) muscles. (R) Hematoxylin and eosin stain of AAV-CMV-GFP–injected muscle. (U-T) Muscle injected with AAV-C5/12-OVA, day 10 after gene transfer. Panel T is hematoxylin and eosin stain; panel U is immunofluorescence stain for CD8 (green) and OVA (red). Original magnification × 200 (Q-U).