Figure 3.

The period of DH01 RPE allograft loss in the SRS of healthy nonimmunosuppressed C57BL/6 mice is characterized by infiltrating cells expressing markers of macrophages (CD11b and F4/80) and neutrophils (Gr1 Ly-6G), but not by T lymphocytes (CD3-∊). (A) Representative confocal microscopy images of sections immunolabeled for SV40T (FITC, green) to identify transplanted cells, and also immunolabeled for either CD11b (a–d), F4/80 (e–h), Gr1 Ly-6G (i–l), or CD3-∊ (m–p) to identify infiltrating cells (all TRITC, red). All nuclei were counterstained with DAPI (blue). At POD 1, the subretinal graft site is primarily composed of SV40T⁺ graft cells, but by POD 7 the proportion of cells in the subretinal bolus expressing this graft cell marker has considerably decreased. CD11b⁺ (a–c), F4/80⁺ (e–y), and Gr1 Ly-6G⁺ (i–k) cells infiltrate the graft in increasing numbers between POD 1 and POD 7. No graft cells are seen at POD 28 (d, h, l, p). One of four eyes assessed at POD 28 still had cells in the SRS, and these are F4/80⁺ (h). Graft cell loss is not associated with CD3-∊⁺ T-lymphocyte infiltration (m–p). Scale bars: 50 μm, 20 μm (high-power insets). (B) Quantitative analysis of the areas of immunolabeling confirms that the period of significant (^*p < 0.05) graft cell loss coincides with significant (^*p < 0.05) infiltration of the SRS by CD11b⁺, F4/80⁺, and Gr1 Ly-6G⁺ cells between POD 1 and POD 7. These innate immune cells predominate over SV40T⁺ graft cells by POD 7. CD3-∊ immunolabeling remains low across all time points and does not differ significantly between time points.