Figure 2.

Antigen-specific enrichment and proliferation of naïve CD4⁺ T cells in scaffolds. A: C57BL/6 mice were intravenously injected with 3 × 10⁶ OT-II/GFP CD4⁺ T cells and implanted with OVA and control scaffolds on opposite flanks. After 7 days, scaffold-derived T cells were analyzed by flow cytometry. Representative FACS plots show the frequencies of OT-II/GFP CD4⁺ T cells in OVA and control scaffolds. Cells are pregated on live CD4⁺ T cells. B: Scaffold T-cell frequencies were determined in six mice. C: CD4⁺ T cells were enriched from OT-II/GFP mice and labeled with CellTrace Violet dye. The labeled cells were transferred intravenously into C57BL/6 mice that contained either OVA or control scaffolds implanted subcutaneously. After 8 days, the cells in the scaffolds were analyzed by flow cytometry. The histograms indicate the level of CellTrace Violet dye fluorescence of gated TCR Vβ5.1⁺ CD4⁺ GFP⁺ cells from scaffolds, spleens, and the inguinal lymph nodes of the recipients. Lower levels of fluorescence indicate greater proliferation. Shaded control histograms indicate the background fluorescence of unlabeled host TCR Vβ5.1⁺ T cells. Scaf^Ctrl, control scaffolds; Scaf^OVA, OVA-loaded scaffolds.