FIGURE 2.

Evidence for complete organ-specific chimerism in B6 → C2D chimeric hearts and spleens. a, Control C57 BL/6, B6 → C2D, and C2D → B6 chimeric hearts were digested into single-cell suspensions (n = 3 hearts digested/group). C57BL/6 control hearts demonstrated significant numbers of CD45⁺ MHC class II⁺(I-A^b) cells, whereas C2D control hearts demonstrated undetectable MHC class II⁺ cells. B6 → C2D chimeric hearts demonstrated significant numbers of MHC class II⁺ cells with virtually all of these being GFP⁺ (of bone marrow donor origin). Additionally, C2D → B6 chimeric hearts demonstrated <1% CD45⁺ MHC class II⁺ cells, with the vast majority of MHC class II⁺ cells being CD45⁻ (presumably graft somatic cells). b, Control B6, B6 → C2D, and C2D → B6 chimeric spleens were also digested with collagenase A and DNase to control for the heart digest procedure (n = 3 spleens digested/group). B6 control spleens demonstrated nearly 100% of MHC class II⁺ cells being CD45⁺. C2D control spleens demonstrated undetectable MHC class II⁺ cells. B6 → C2D chimeric spleens demonstrated >99% of MHC class II⁺ cells being GFP⁺ (of donor origin) and C2D → B6 chimeric spleens demonstrated a near complete lack of MHC class II⁺ cells (0.02% of the total number of cells), with <0.03% of CD45⁺ cells being MHC class II⁺.