Figure 2.

Regulatory T Cells Infiltrate the Muscle after rAAV1 IM Injection

Nonhuman primates were injected IM, VLP, or IAPD with an ssAAV1 vector (6e12 vg/kg). Muscles were harvested 21 and 60 days after dosing and were dissociated as described in the Materials and Methods section. Regulatory T cell population was analyzed by flow cytometry. (A) Gating strategy. RA1683, right quadriceps (injected muscle), 60 days after dosing. T cells are gated as CD3⁺ cells in the lymphocyte subset, CD4 T cells are gated as CD3⁺ CD4⁺ cells in the CD3⁺ subset, and Tregs are gated as Helios⁺Foxp3⁺ cells in the CD3⁺ CD4⁺ subset. (B and C) Percentage of CD4 T cells (B) and Tregs (C) in injected muscle or perfused limb (right quadriceps) at day 21 and day 60 after dosing. nd, not detected. (D) Detection of Tregs by immunohistochemistry in injected muscle after IM delivery (RA0764, day 60 post-injection). Scale bars, 10 μm. SS, side scatter; FSC, forward scatter.