FIG. 1.

Chemokine receptor expression on human thymocytes. (A) Anti-CCR4 MAb 328B, anti-CCR5 MAb 2D7-APC, anti-CCR7 MAb 6B3, anti-CXCR4 MAb 12G5-PE, and isotype control MAb were incubated with freshly isolated cells derived from SCID-hu mice. Cells were washed and resuspended in PBS plus 2% formaldehyde (CCR5 and CXCR4 stains) or incubated with goat anti-mouse IgG-FITC (CCR4 and CCR7 stains) prior to washing and fixation with PBS–2% formaldehyde. Data were collected and analyzed with a FACSCalibur flow cytometer and CellQuest software. Thymocytes were analyzed by excluding other cells based on their low angle and 90° light scatter. Isotype control MAb were used to define the marker denoting positive staining. (B) SCID-hu thymus-liver graft cells were isolated and incubated with CD4-peridinin chlorophyll protein, CD8-FITC, anti-CCR5-APC, anti-CXCR4-PE, or isotype control MAb conjugated to each of the same fluorochromes. The cells were prepared, run, and analyzed as for panel A except that the CD4 and CD8 stains were used to differentiate the anti-CCR5 and anti-CXCR4 immunofluorescence of the major thymocyte subsets.