Induction of interleukin-10 expression through Fcα receptor in human monocytes and monocyte-derived dendritic cells: role of p38 MAPKinase

As previously reported by others for immunoglobulin (Ig)G, we observed that IgA can induce interleukin (IL)-10 expression in human monocytes. In this study, we explored the molecular mechanisms of IL-10 induction by IgA in monocytes and monocyte-derived dendritic cells (MD-DCs). Monomeric IgA induced IL-10 production in monocytes and this production was further increased upon IgA cross-linking. Similar IL-10 responses were observed in monocytes and autologous MD-DCs, and were inhibited (by similar to 77%) by preincubation with a blocking mAb to Fc alpha RI. IL-10 induction by IgA correlated with activation of MAPKinases ERK1/2, p38 and JNK, whereas only p38-inhibitor SB-203580 inhibited IL-10 induction. Upon IgA stimulation, AP-1, NF kappa B and Sp1 transcription factors were activated and inhibitors of NF kappa B and of Sp1 suppressed IgA-driven transcriptional activation of IL-10. In addition, p38 MAPK activation appeared that it was required to control nuclear translocation of NF kappa B and Sp1 upon IgA stimulation. Therefore, in human monocytes and MD-DCs the mechanisms of IL-10 induction by IgA involve p38 MAPK-dependent recruitment of both NF kappa B and Sp1. Immunology and Cell Biology (2010) 88, 486-493; doi: 10.1038/icb.2009.120; published online 19 January 2010