Article
Breg-mediated CD4+ T cell suppression is mainly induced by co-inhibitory molecules and can be enhanced by presence of IL-10 and ß-adrenergic receptor activation
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Authors
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Nadine Honke
- Poliklinik und Funktionsbereich für Rheumatologie & Hiller Forschungszentrum Rheumatologie, Universitätsklinikum Düsseldorf, Düsseldorf
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Birgit Opgenoorth
- Poliklinik und Funktionsbereich für Rheumatologie & Hiller Forschungszentrum Rheumatologie, Universitätsklinikum Düsseldorf, Düsseldorf
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Matthias Schneider
- Poliklinik und Funktionsbereich für Rheumatologie & Hiller Forschungszentrum Rheumatologie, Universitätsklinikum Düsseldorf, Düsseldorf
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Georg Pongratz
- Poliklinik und Funktionsbereich für Rheumatologie & Hiller Forschungszentrum Rheumatologie, Universitätsklinikum Düsseldorf, Düsseldorf
| Published: | September 9, 2020 |
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Outline
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Introduction: Regulatory B cells (Bregs) can inhibit inflammation mediated by CD4+ T cells, a crucial population in the pathogenesis of rheumatoid arthritis (RA). Recently, we were able to show that B cells produce their own catecholamines to modulate Breg function. In the current study, we tested if an additional ß-adrenergic receptor (ß-ADR) stimulus can enhance the suppression of CD4+ T cells. Moreover, we investigated the importance of co-inhibitory molecules (PD-L1/FasL) and of the anti-inflammatory cytokine IL-10 in the suppression of CD4+ T cells.
Methods: On activated murine B cells or B cells and splenocytes from collagen-induced arthritis (CIA) mice, modulation of Bregs and their effect on CD4+ T cell proliferation was examined. Pre-inactivated or pre-activated B cells and CD3/CD28-activated splenocytes were cocultured or separately cultivated by using transwells in the presence or absence of an anti-IL-10-depleting antibody for 72h. CD4+ T cell proliferation and PDL-1/FasL expression on B cells was monitored by FACS. B cell-derived IL-10 was measured in the supernatant by ELISA.
Results: FACS analysis showed that CpG-activated Bregs have the ability to suppress CD4+ T cell proliferation (C vs. CpG, n=12, p****<0.0001). This suppression was associated with elevated IL-10 production (C vs. CpG, n= 8, p****<0.0001) and PDL-1/FasL expression (C vs. CpG, n = 11-12, p ****=<0,0001/p***=0,0006). Addition of ADR-ß agonists norepinephrine (NE) or isoproterenol (Isopr.) to CpG-activated Bregs further enhanced suppression of CD4+ T cell proliferation (CpG vs. CpG/NE, n=12, p*=0,0465; CpG vs. CpG/Isopr., n=12, p***=0,0006). This higher suppression correlates with enhanced IL-10 production by Bregs (CpG vs. CpG+Isopr., n=8, % rel. to control ~40%, p**=0,0045; CpG vs. CpG+NE, n=8, % rel. to control ~16%, p**=0,0012). Presence of IL-10 in co-culture experiments enhanced suppression of CD4+ T cell proliferation (CpG vs. CpG+anti-IL-10, n= 6, p**=0,0019) while IL-10 in transwells promotes CD4+ T cell proliferation (CpG vs. CpG + anti-IL-10, n = 6, p****<0,0001).
Conclusion: In conclusion, our data suggest that CpG-activated Bregs primarily suppress CD4+ T cell proliferation in a cell-cell-contact-dependent way and that this suppression is enhanced by additional presence of IL-10 and ß-ADR signaling. These pathways could also be used to modulate Breg function for therapeutic purposes.
Disclosures: None declared
