Figure 1.

CD117⁺ expression is induced on CD8⁺ T cells following recent activation. (A) mRNA transcripts of both isoforms of CD117 are upregulated in enriched CD8⁺ T_N cells from UCB activated with anti-CD3 plus IL-2 for 5 days and then maintained in IL-7 for 2 weeks, as compared to resting T_N from UCB. Transcriptome analysis was performed on three different samples for each type of cells. The heat map shows down-regulated genes in blue and up-regulated genes in orange, scale: log2 normalized intensity. (B) CBMC were activated at day 0 and day 12 with anti-CD3 plus IL-2 and at day 21 stained with different clones of CD117-specific MoAbs, as indicated. Histograms show the results of gating on CD3⁺CD8⁺ cells. The dotted lines indicate the isotype controls, one for each company, since the antibodies are all IgG1. A single representative experiment out of three is shown. (C) CBMC at day 7 after activation were incubated overnight with escalating doses of soluble SCF and the expression of CD117 was then determined. Histograms show the results of gating on CD3⁺/CD8⁺ cells. A single representative experiment out of three is shown. (D) CBMC were activated with anti-CD3 plus IL-2 and the kinetics of CD117 expression was recorded, gated on either CD3⁺CD8⁺ or CD3⁺CD4⁺ cells. Data are from six independent cord blood samples.