Glatiramer acetate treatment normalized the monocyte activation profile in MS patients to that of healthy controls.

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system, and monocytes contribute to MS-associated neuroinflammation. While classically activated monocytes promote inflammation, type II-activated monocytes improve the course of MS. This study investigated type II activation of monocytes and their two main subsets, namely CD14+ (CD14++CD16- subset) and CD16+ monocytes (CD14+CD16+ subset), by glatiramer acetate (GA) or intravenous immunoglobulin-associated immune complexes (IC), both of which are known MS treatments. Total monocytes and subsets were isolated from peripheral blood mononuclear cells (PBMC) of healthy controls, untreated MS patients (MS) and GA-treated MS patients (GA-MS). In contrast to the more activated ex vivo profile of monocytes from the MS group, monocytes from the GA-MS group resembled those from healthy controls. In vitro type II activation with GA primarily reduced CD40, CD86 and IL-12p40 whereas type II activation with IC consistently reduced CD40 but increased interleukin-10 (IL-10), suggesting that the GA and IC activation pathways are distinct. Moreover, while GA treatment reduced IL-12p40 by both CD14+ and CD16+ subsets, IC treatment only enhanced IL-10 by the CD16+ subset. Further analysis of the CD16+ subset revealed that MS patients had a greatly expanded CD14+CD16int population while both CD14+CD16int and CD14lowCD16high monocyte populations were expanded in GA-MS patients. Finally, a global analysis of the ex vivo monocyte data indicated that GA treatment distinctly altered the monocyte profile of MS patients, further supporting the idea that GA directly targets monocytes.

Expansion and preferential activation of the CD14(+)CD16(+) monocyte subset during multiple sclerosis.

Multiple sclerosis (MS) is an immune-driven, demyelinating disease of the central nervous system (CNS). Although many types of immune cells are involved in disease progression, activated monocytes are believed to be one of the first to arrive to the brain and initiate inflammation. However, little is known about how the two main monocyte subsets, CD14(++)CD16(-) and CD14(+)CD16(+), are involved in MS. To understand how the phenotype and responses of these monocyte subsets are altered during MS, total monocytes and the purified monocyte subsets from healthy subjects (n=29) and MS patients (n=20) were characterized ex vivo and stimulated in vitro with lipopolysaccharide (LPS). The ex vivo analyses showed that total monocytes from MS patients had significantly elevated levels of CD40, CD86, HLA-DR, CD64 and C-C motif chemokine receptor 2 (CCR2), and this elevation was most marked on CD16(+) monocytes. In vitro stimulation with LPS led to an increase in CD86, HLA-DR, CD64 and IL-6 production by monocytes from MS patients. Furthermore, in purified cultures, CD14(+) monocytes were found to be the main producers of IL-10 while CD16(+) monocytes produced more IL-12. In monocytes from MS patients, both subsets produced substantially more IL-6, and the production of IL-10 by the CD16(+) subset was also significantly elevated compared with healthy monocytes. Together these findings highlight the important contribution of the CD16(+) monocyte subset in driving inflammatory responses during MS.

Type II-activated murine macrophages produce IL-4.

BACKGROUND: Type II activation of macrophages is known to support Th2 responses development; however, the role of Th2 cytokines (esp. IL-4) on type II activation is unknown. To assess whether the central Th2 cytokine IL-4 can alter type II activation of macrophages, we compared the ability of bone marrow-derived macrophages from wild type (WT) and IL-4Rα-deficient mice to be classically or type II-activated in vitro. RESULTS: We found that although both WT and IL-4Rα-deficient macrophages could be classically activated by LPS or type II activated by immune complexes plus LPS, IL-4Rα-deficient macrophages consistently produced much higher levels of IL-12p40 and IL-10 than WT macrophages. Additionally, we discovered that type II macrophages from both strains were capable of producing IL-4; however, this IL-4 was not responsible for the reduced IL-12p40 and IL-10 levels produced by WT mice. Instead, we found that derivation culture conditions (GM-CSF plus IL-3 versus M-CSF) could explain the different responses of BALB/c and IL-4Rα-/- macrophages, and these cytokines shaped the ensuing macrophage such that GM-CSF plus IL-3 promoted more IL-12 and IL-4 while M-CSF led to higher IL-10 production. Finally, we found that enhanced IL-4 production is characteristic of the type II activation state as other type II-activating products showed similar results. CONCLUSIONS: Taken together, these results implicate type II activated macrophages as an important innate immune source of IL-4 that may play an important role in shaping adaptive immune responses.

Induction of IL-lα mRNA Expression by 17β-Estradiol in Normal Human Keratinocytes

No abstract available.