Figure 3. Migration pattern of the systemically administered MDSC.

(A) MDSC preferably migrate to islet allografts. 2 × 10⁶ MDSC generated from normal B6 mice (CD45.2) mice were i.v. injected into the congenic mice (CD45.1) immediately after transplantation of BALB/c islets. Leukocytes were isolated on POD 1, 2, 4 and 7 from islet allografts, draining lymph node (dLN) and spleen, and stained for CD11b and CD45.2 for flow analysis gated on CD11b⁺ population. The data show mean percentage of CD45.2⁺ cells ± SD (n=3) (p<0.05, graft vs. spleen or dLN at all time points). (B) Migration of MDSC to islet allografts requires CCR2. In a separate study, MDSC were generated from CCR2^−/− mice, instead of WT mice, and i.v. injected into the congenic mice (CD45.1) immediately after transplantation of BALB/c islets. Leukocytes were isolated on POD 1, 2, 4 and 7 from islet allografts, and stained with anti-CD11b, CD45.1 and CD45.2 mAbs for low analysis. The number is percentage of CD45.1⁺ or CD45.2⁺ cells gated on CD11b⁺ cell population. The data are representative of three separate experiments.