Increased IL-23 secretion and altered chemokine production by dendritic cells upon CD46 activation in patients with multiple sclerosis

Abstract

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). In MS, myeloid dendritic cells (mDCs) secrete elevated amounts of IL-23, a potent proinflammatory cytokine, compared to healthy donors. Here, we examined the role of CD46, a complement binding factor, in mDCs by analyzing cytokine and chemokine production in healthy donors and patients with MS. There were striking differences between these groups with increased IL-23p19, CCL3 and CCL5 production, but decreased CCL2 levels in patients. This demonstrates major differences of DC activation upon CD46 activation, with a potential role in the pathogenesis of MS.

Figure 1. IL-12 and IL-23 production by CD46-activated mDCs

(A) The production of IL-12 and IL-23 by CD46-activated mDCs was quantified by qPCR. Isolated mDCs from 10 healthy donors were matured in presence of LPS in presence or absence of anti-CD46 antibodies. After 48h, RNA were isolated and cytokine production examined by qPCR. (B) The amounts of IL-12p40 and IL-12 p70 secreted by mDC in presence of absence of CD46 were also quantified by ELISA (C) The amount of IL-17 produced by activated T cells cultured in presence of supernatants from mature mDCs with or without anti-CD46 was determined by ELISA. The addition of sIL-23R in the T cell culture blocked IL-17 induction.

Figure 2. Increased IL-23p19 production in patients with MS

The induction of IL-12p35 (A) and IL-23p19 (B) upon CD46 activation was assessed in healthy controls (HC) and patients with MS (MS). Isolated mDCs from 10 untreated patients with MS in the relapsing-remitting phase and of 10 healthy donors were matured in presence of LPS in presence or absence of anti-CD46 antibodies. After 48h, RNA were isolated and cytokine production examined by qPCR. The induction of both IL-12 and IL-23 upon CD46 activation was calculated.

Figure 3. Chemokine production by CD46-activated mDCs

(A) The productions of CCL2, CCL3 and CCL5 by mature mDCs obtained by culture with LPS in presence or absence of CD46 antibodies were measured by qPCR (A) in a cohort of 8 healthy donors and 9 untreated patients with MS in the relapsing-remitting phase. Their relative expression compared to immature mDCs is plotted. (B) The amounts of CCL2, CCL3 and CCL5 secreted by mDC activated by CD46 (or irrelevant IgG1) were assessed by ELISA.