G-CSF treatment in vivo leads to an up-regulation of GATA-3 and increase of spontaneous IL-4 secretion in T cells. G-CSF treatment in vivo leads to an up-regulation of GATA-3 and an increase of spontaneous IL-4 secretion in T cells of healthy stem cell donors. (A) Western blot analysis of CD3⁺ and CD4+ T cells confirmed the up-regulation of GATA-3 upon G-CSF treatment in vivo at the protein level in 6 individual donors with increases up to 1.8-fold in CD3⁺ and 2.6-fold in CD4+ T cells (Western blots of representative donors are shown). The T-cell leukemia cell line MOLT-4 served as a positive control (P). ϕ indicates no in vitro stimulation. (B) The production of IL-4 as representative cytokine for a Th2 immune response was quantified in CD3⁺ T cells before (top panels) and after (bottom panels) G-CSF treatment by ELISPOT analysis. PHA-stimulated PBMCs served as a positive control, and cell-free medium served as a negative control. The number of spot-forming units is shown in dependence of their intensity determined by ELISPOT Reader Software. G-CSF treatment resulted in a 10- to 20-fold increase of spontaneous IL-4 secretion by CD3⁺ T cells in 3 different donors analyzed (1 representative donor is shown). Original magnification, × 20.