TABLE 1.
Effects of cytokines on CXCR4 expression in thymocytesa
| Cytokine | Mean fluorescence intensity of CXCR4 on CD3+/high cells (% CD3+/high/CXCR4+ cells)b
|
|||
|---|---|---|---|---|
| Expt 1 | Expt 2 | Expt 3 | Expt 4 | |
| None | 47 (3) | 38 (2) | 37 (6) | 37 (5) |
| IL-2 | 60 (9) | 118 (21) | 139 (28) | ND |
| IL-4 | 444 (22) | 354 (24) | 359 (29) | 256 (15) |
| IL-7 | ND | 70 (25) | ND | 160 (24) |
| IL-2 + IL-4 | 431 (29) | 489 (33) | 361 (35) | ND |
| IL-4 + IL-7 | ND | 398 (33) | ND | 326 (17) |
Freshly isolated thymocytes were cultured for 2 weeks in serum-free medium in the presence or absence of cytokines. Surface expression of CXCR4 was determined by flow cytometry using directly conjugated antibodies specific for CD3 (FITC) and CXCR4 (PE), with 7-AAD used to exclude dead cells.
The geometric mean of the fluorescence intensity of CXCR4 in the CD3+/high population and the percentage of these cells in the gated population were calculated with the Cell Quest software. Cursors were set by using isotype controls for all cytokine conditions within an individual experiment. Single-color staining with CD3-FITC was used to identify the CD3+/high population. Note that the percentage of total CD3+/high cells depended on the cytokine used (Fig. 2A). ND, not determined.