PRODUCTION OF INTERLEUKIN-10 BY GRANULOCYTE-COLONY-STIMULATING FACTOR-MOBILIZED BLOOD PRODUCTS - A MECHANISM FOR MONOCYTE-MEDIATED SUPPRESSION OF T-CELL PROLIFERATION
M. Mielcarek et al., PRODUCTION OF INTERLEUKIN-10 BY GRANULOCYTE-COLONY-STIMULATING FACTOR-MOBILIZED BLOOD PRODUCTS - A MECHANISM FOR MONOCYTE-MEDIATED SUPPRESSION OF T-CELL PROLIFERATION, Blood, 92(1), 1998, pp. 215-222
Previous reports showed that granulocyte colony-stimulating factor (G-
CSF)-mobilized peripheral blood mononuclear cells (G-PBMC) are hypores
ponsive to alloantigen compared with control PBMC. In the current stud
y, neutralizing antibodies to interleukin-10 (IL-10) increased the pro
liferative response of G-PBMC to alloantigen by 50.14% (+/- 12.79%; n
= 8), whereas the proliferative response of control PBMC was not affec
ted. The inhibition of OKT3-stimulated CD4 cell proliferation by G-PBM
C-derived CD14(+) cells could also be abrogated by the addition of IL-
10 neutralizing antibodies. Further, IL-10 levels correlated with the
number of CD14 cells in these cultures. Constitutive IL-10 mRNA levels
detected by quantitative reverse transcriptase polymerase chain react
ion (RT-PCR) were 10-fold higher in G-PBMC compared with control PBMC,
This translated into significantly higher IL-10 levels after 24-hour
lipopolysaccharide (LPS) stimulation of G-PBMC compared with control P
BMC (P = .036), IL-10 mRNA levels were also fivefold higher in isolate
d G-PBMC-derived CD14 cells compared with control CD14 cells. This cor
responded to increased constitutive production of IL-10 by isolated G-
PBMC-derived CD14 cells compared with control CD14 cells (357.2 +/- 10
4.5 v 51.7 +/- 30.5, P = .051). In conclusion, these data suggest that
monocytes contained within G-PBMC, which, in comparison to marrow, ar
e increased in absolute number and relative proportion to T cells, may
suppress T-cell responsiveness by secretion of IL-10. (C) 1998 by The
American Society of Hematology.