Effect of CXCL12 on monocyte-DCs differentiation and maturation and immunogenic function. (A) PBMos were treated with GM-CSF and IL-4, in the presence of CXCL12 (100 ng/mL) for 3 days. The expression of CD14 and CD1a was analyzed by flow cytometry. Fold regulation relative to control untreated cells are shown. Mean ± SD; n = 5; *P < .05. (B) PBMos were derived to DCs with GM-CSF and IL-4, in the presence of CXCL12 (100 ng/mL), during the differentiation process. Inmature DCs or LPS-matured DCs were stained with a panel of mAb as indicated. The regions of positive cells were selected using the matched isotype control for each mAb. A representative experiment out of 10 is presented. MFI of positive cells is shown (C) CFSE-labeled autologous T lymphocytes were cocultured with unloaded, PPD- or TT-loaded c-DCs and CXCL12-DCs, at 1:10 DC:T ratio. After 6 days, lymphocytes were harvested, and the percentages of proliferating T cells (CFSElow) were calculated. CXCL12-DCs induced lower CD4⁺ T lymphocyte proliferation than c-DCs, both in PPD- and TT-specific responses, as shown in 2 representative donors (D#1 and D#2), from 4 individual donors with similar results. Unpulsed c-DCs and CXCL12-DCs served as controls. The frequency of CD4⁺ T cells in each CFSE-dilution peak for PPD-specific proliferative responses of D#1 is shown in the right panels.