GM-CSF and IL-4 Stimulate Antibody Responses in Humanized Mice by Promoting T, B, and Dendritic Cell Maturation

GM-CSF activates hematopoietic cells and recruits neutrophils and macrophages to sites of inflammation. Inhibition of GM-CSF attenuates disease activity in models of chronic inflammatory disease. Effects of GM-CSF blockade were linked to modulation of the effector phase, whereas effects on early pathogenic events, for example, Ab production, have not been identified. To evaluate yet uncharacterized effects of GM-CSF on early pathogenic events in chronic inflammation, we employed immunization-induced epidermolysis bullosa acquisita (EBA), an autoimmune bullous disease caused by autoantibodies to type VII collagen. Compared to wild-type mice, upon immunization, GM-CSF−/− mice produced lower serum autoantibody titers, which were associated with reduced neutrophil numbers in draining lymph nodes. The same effect was observed in neutrophil-depleted wild-type mice. Neutrophil depletion in GM-CSF−/− mice led to a stronger inhibition, indicating that GM-CSF and neutrophils have additive functions. To characterize the contribution of GM-CSF specifically in the effector phase of EBA, disease was induced by transfer of anti–type VII collagen IgG into mice. We observed an increased GM-CSF expression, and GM-CSF blockade reduced skin blistering. Additionally, GM-CSF enhanced reactive oxygen species release and neutrophil migration in vitro. In immunization-induced murine EBA, treatment with anti–GM-CSF had a beneficial effect on established disease. We demonstrate that GM-CSF modulates both autoantibody production and skin blistering in a prototypical organ-specific autoimmune disease.

Section: Discussionmentioning

confidence: 99%

Section: Anti-gm-csf Treatment Delays Disease Progression In Already mentioning

confidence: 99%

mentioning

confidence: 99%

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GM-CSF Modulates Autoantibody Production and Skin Blistering in Experimental Epidermolysis Bullosa Acquisita

Samavedam

Iwata

Müller

et al. 2014

“…3C), suggesting that Treg cells have an inducible phenotype (36). TGF-b is one of the key negative regulators of immune homeostasis, suppressing autoreactive T cell expansion via the inhibition of MHC class I and II expression on APCs (37) Although we did not study the B cell reconstitution, which may mediate secondary autoimmunity in ∼25-30% of alemtuzumabtreated patients, IL-4, TGF-b, and IL-10 produced by the reconstituting T cells may contribute to the B cell maturation (40), regulation of Ab isotypes (41), and the induction of Ab production (42). This may contribute to the induction of secondary autoimmune diseases, which was in our study detected in only one patient who developed immune thrombocytopenia 9 mo after second infusion of alemtuzumab.…”

Section: Discussionmentioning

confidence: 99%

Differential Reconstitution of T Cell Subsets following Immunodepleting Treatment with Alemtuzumab (Anti-CD52 Monoclonal Antibody) in Patients with Relapsing–Remitting Multiple Sclerosis

Zhang

Tao

Chopra

et al. 2013

145

Alemtuzumab (anti-CD52 mAb) provides long-lasting disease activity suppression in relapsing–remitting multiple sclerosis (RRMS). The objective of this study was to characterize the immunological reconstitution of T cell subsets and its contribution to the prolonged RRMS suppression following alemtuzumab-induced lymphocyte depletion. The study was performed on blood samples from RRMS patients enrolled in the CARE-MS II clinical trial, which was recently completed and led to the submission of alemtuzumab for U.S. Food and Drug Administration approval as a treatment for RRMS. Alemtuzumab-treated patients exhibited a nearly complete depletion of circulating CD4+ lymphocytes at day 7. During the immunological reconstitution, CD4+CD25+CD127low regulatory T cells preferentially expanded within the CD4+ lymphocytes, reaching their peak expansion at month 1. The increase in the percentage of TGF-β1–, IL-10–, and IL-4–producing CD4+ cells reached a maximum at month 3, whereas a significant decrease in the percentages of Th1 and Th17 cells was detected at months 12 and 24 in comparison with the baseline. A gradual increase in serum IL-7 and IL-4 and a decrease in IL-17A, IL-17F, IL-21, IL-22, and IFN-γ levels were detected following treatment. In vitro studies have demonstrated that IL-7 induced an expansion of CD4+CD25+CD127low regulatory T cells and a decrease in the percentages of Th17 and Th1 cells. In conclusion, our results indicate that differential reconstitution of T cell subsets and selectively delayed CD4+ T cell repopulation following alemtuzumab-induced lymphopenia may contribute to its long-lasting suppression of disease activity.

“…However, human myelopoiesis is not efficient in these models due to a lack of species cross-reactivity of nonhematopoietic cell-derived growth factors including CSF-1, GM-CSF, IL-3, and erythropoietin. This has resulted in poor differentiation and/or function of cells of the monocyte/macrophage lineage unless supported by the addition of human cytokines (22)(23)(24)(25)(26)(27) (28)(29)(30)(31), but whether fully functional specialized myeloid DC subsets develop has not been addressed. Although DC phenotypically resembling human blood CD141 + DC by expression of CD141, CLEC9A, NECL2, and TLR3 were found in spleens of humanized mice, their low frequency has limited functional characterization (7).…”

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confidence: 99%

FLT3-Ligand Treatment of Humanized Mice Results in the Generation of Large Numbers of CD141+ and CD1c+ Dendritic Cells In Vivo

Ding

Wilkinson

Idris

et al. 2014

We established a humanized mouse model incorporating FLT3-ligand (FLT3-L) administration after hematopoietic cell reconstitution to investigate expansion, phenotype, and function of human dendritic cells (DC). FLT3-L increased numbers of human CD141+ DC, CD1c+ DC, and, to a lesser extent, plasmacytoid DC (pDC) in the blood, spleen, and bone marrow of humanized mice. CD1c+ DC and CD141+ DC subsets were expanded to a similar degree in blood and spleen, with a bias toward expansion of the CD1c+ DC subset in the bone marrow. Importantly, the human DC subsets generated after FLT3-L treatment of humanized mice are phenotypically and functionally similar to their human blood counterparts. CD141+ DC in humanized mice express C-type lectin-like receptor 9A, XCR1, CADM1, and TLR3 but lack TLR4 and TLR9. They are major producers of IFN-λ in response to polyinosinic-polycytidylic acid but are similar to CD1c+ DC in their capacity to produce IL-12p70. Although all DC subsets in humanized mice are efficient at presenting peptide to CD8+ T cells, CD141+ DC are superior in their capacity to cross-present protein Ag to CD8+ T cells following activation with polyinosinic-polycytidylic acid. CD141+ DC can be targeted in vivo following injection of Abs against human DEC-205 or C-type lectin-like receptor 9A. This model provides a feasible and practical approach to dissect the function of human CD141+ and CD1c+ DC and evaluate adjuvants and DC-targeting strategies in vivo.