FIG 3.

CXCR2 expression is required for CsA-mediated CD11b⁺ Gr1⁺ myeloid cell recruitment and allograft survival. PBS-treated control and CsA-treated allograft recipient mice were studied. (A and B) On day 10 after allograft skin transplantation, CXCL1, CXCL2, CCL3, and CXCR2 mRNA expression were analyzed by real-time PCR (A), and CXCR2 expression was determined by intracellular staining (B) in splenic CD11b⁺ Gr1⁺ cells isolated from the CsA-treated allograft recipient mice or PBS-treated control mice. The mean fluorescence intensity (MFI) of CXCR2 is summarized in the graph to the right. (C and D) Allograft recipient mice were administered 50 μg neutralizing antibody anti-CXCR2 MAb (catalog no. 242216; R&D Systems) or IgG isotype control (catalog no. 54447; R&D Systems) via i.v. injection 1 h before transplantation and PBS or CsA treatment. Mice were sacrificed on day 8 after allograft skin transplantation, the numbers of allograft local infiltrating CD11b⁺ Gr1⁺ cells were analyzed using flow cytometry (C), and graft survival was determined (D). Data (means plus standard deviations [SDs]) are representative of two (A to D) independent experiments (A and B, n = 3 to 5; C and D, n = 10). Values that are statistically significantly different are indicated by bars (or an arrow) and asterisks as follows: **, P < 0.01; ***, P < 0.001.