Regulation of the Class II MHC Pathway in Primary Human Monocytes by Granulocyte-Macrophage Colony-Stimulating Factor

Abstract

GM-CSF stimulates the growth and differentiation of hematopoietic progenitors and also affects mature cell function. These effects have led to the use of GM-CSF as a vaccine adjuvant with promising results; however, the mechanisms underlying GM-CSF-mediated immune potentiation are incompletely understood. In this study, we investigated the hypothesis that the immune stimulatory role of GM-CSF is in part due to effects on class II MHC Ag presentation. We find that, in primary human monocytes treated for 24–48 h, GM-CSF increases surface class II MHC expression and decreases the relative level of the invariant chain-derived peptide, CLIP, bound to surface class II molecules. GM-CSF also increases expression of the costimulatory molecules CD86 and CD40, but not the differentiation marker CD1a or CD16. Furthermore, GM-CSF-treated monocytes are better stimulators in a mixed leukocyte reaction. Additional analyses of the class II pathway revealed that GM-CSF increases total protein and RNA levels of HLA-DR, DM, and DOα. Expression of class II transactivator (CIITA) types I and III, but not IV, transcripts increases in response to GM-CSF. Furthermore, GM-CSF increases the amount of CIITA associated with the DR promoter. Thus, our data argue that the proinflammatory role of GM-CSF is mediated in part through increased expression of key molecules involved in the class II MHC pathway via induction of CIITA.

Differential immunostimulating effect of Granulocyte-macrophage colony-stimulating factor (GM-CSF), Granulocyte colony-stimulating factor (G-CSF) and Interferon γ (IFNγ) after severe trauma

“…CIITA expression is regulated transcriptionally and both IFNg and GM-CSF were shown to elevate MHC class-2 via increased expression of CIITA molecules in isolated human monocytes [26]. In this in vitro study the effects of GM-CSF on HLA-DR expression peaked 24-48 h after incubation, which again suggests that the in vitro incubation period of 6 h was not suffi cient to reach maximal effects in our study.…”

“…Especially GM-CSF and IFN-g are known to induce the production of pro-infl ammatory cytokines such as TNFa alone or after secondary stimulation [4,5,6], while G-CSF results in a mixed pattern with enhanced pro-and anti-infl ammatory mediator expression [7]. Both GM-CSF and IFN-g upregulate HLA-DR surface expression, although partly different regulatory mechanisms are postulated [8,9,10]. G-CSF, GM-CSF and IFN-g have been analysed separately in terms of immunomodulatory capacity in in vitro approaches or preliminary therapeutic trials.…”

What determines the success or failure of intracellular cutaneous parasites? Lessons learned from leishmaniasis

“…However, after infection with Leishmania parasites, M express only low levels of MHC and costimulatory molecules before activation, they do not actively migrate to draining lymph nodes and are not capable of T cell priming against L. major [40,41]. Later on, in established infections, M develop into more potent APC by exposure to mediators such as IFN-and GM-CSF [42]. In addition, phagocytosis of L. major amastigotes at later stages post infection via diVerent receptors leads to M activation [11].…”

Interleukin-27 upregulates major histocompatibility complex class II expression in primary human endothelial cells through induction of major histocompatibility complex class II transactivator

“…The primer pairs for CIITA isoforms I, III and IV have been described previously [17]. Other primer sets used were: DRA, 5Ժ-GCTCTGAGTGGCGAAATCAAG and 5Ժ-CAATGCTAGGTACTGCGGGAG; IRF-1, 5Ժ-AAGGATGCCTGTTT-GTTCCG and 5Ժ-CAGCGAAAGTTGGCCTTCC; and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 5Ժ-TGGGCTACACTGAGCACCAG and 5Ժ-GGGTGTCGCTGTTGAAGTCA.…”