Integrated Analysis of Cytokine Profiles in Malaria Patients Discloses Selective Upregulation of TGF-ß1, ß3, and IL-9 in Mild Clinical Presentation.

The proper control of Plasmodium infection requires a finely balanced immune response. Here, we evaluated the implication of TGF-ß1 and TGF-ß3 in this process using novel monoclonal antibodies to measure their plasma concentrations in comparison with other cytokines and the expression of FOXP3 mRNA. Plasma cytokine levels were measured in 80 patients with severe anaemic malaria and 186 with a mild presentation using ELISA, and rtPCR was used to measure FOXP3 mRNA expression. While no mature TGF-ß isoforms were detected in the plasma, the latent TGF-ß1 and TGF-ß3 were strongly upregulated in patients with mild malaria and nearly undetected in patients with severe disease. Similar selective upregulation in mild patients was observed for IL-9 and FOXP3 mRNA, while IL-7, IL-10, IL-17, and IL-27, although higher in mild cases, were also detected in severe disease. In contrast, a clearly skewed trend of severe cases towards higher pro-inflammatory (IL-6, IL-13, TNF-α) and Th1 (IFN-γ) responses was observed, which was associated with a higher level of parasitaemia as well as lower IgG and higher IgM responses. Together, these results suggest that the stimulation of regulatory T cells through TGF-ß1/TGF-ß3 and IL-9 is paramount to an effective and balanced protective immunity in natural human malaria infection.

A Targetable, Noncanonical Signal Transducer and Activator of Transcription 3 Activation Induced by the Y-Less Region of IL-22 Receptor Orchestrates Imiquimod-Induced Psoriasis-Like Dermatitis in Mice.

Exacerbated IL-22 activity induces tissue inflammation and immune disorders such as psoriasis. However, because IL-22 is also essential for tissue repair and defense at barrier interfaces, targeting IL-22 activity to treat psoriasis bears the risk of deleterious effects at mucosal sites such as the gut. We previously showed in vitro that IL-22 signaling relies on IL-22 receptor alpha (IL-22Rα) Y-dependent and -independent pathways. The second depends on the C-terminal Y-less region of IL-22Rα and leads to a massive signal transducer and activator of transcription 3 (STAT3) activation. Because STAT3 activation is associated with the development of psoriasis, we hypothesized that the specific inhibition of the noncanonical STAT3 activation by the Y-less region of IL-22Rα could reduce psoriasis-like disease while leaving intact its tissue defense functions in the gut. We show that mice expressing a C-terminally truncated version of IL-22Rα (ΔCtermut/mut mice) are protected from the development of psoriasis-like dermatitis lesions induced by imiquimod to a lesser extent than Il22ra-/- mice. In contrast, only Il22ra-/- mice lose weight after Citrobacter rodentium infection. Altogether, our data suggest that specific targeting of the noncanonical STAT3 activation by IL-22 could serve to treat psoriasis-like skin inflammation without affecting IL-22‒dependent tissue repair or barrier defense at other sites.

Novel antibodies that selectively block mouse IL-12 enable the re-evaluation of the role of IL-12 in immune protection and pathology.

The dimeric cytokine IL-12 is important in the control of various infections but also contributes to the pathology of certain diseases making it a potential target for therapy. However, its specific inhibition with antibodies is complicated by the fact that its two subunits are present in other cytokines: p40 in IL-23 and p35 in IL-35. This has led to erroneous conclusions like the alleged implication of IL-12 in experimental autoimmune encephalomyelitis (EAE). Here, we report the development of a mouse anti-mouse IL-12 vaccine and the production of monoclonal antibodies (mAbs) that do not react with p40 or p35 (in IL-35) but specifically recognize and functionally inhibit the IL-12 heterodimer. Using one of these mAbs, MM12A1.6, that strongly inhibited IFN-γ production and LPS-induced septic shock after viral infection, we demonstrate the critical role played by IL-12 in the rejection of male skin graft by female C57BL/6 syngeneic recipients and in the clearance of an immunogenic mastocytoma tumor variant by DBA/2 mice, but not in a parent to F1 immune aggression model nor in MOG-induced EAE, which was clearly prevented by anti-p40 mAb C17.8. Given this selective inhibition of IL-12, these mAbs provide new options for reassessing IL-12 function in vivo.

IL-24 contributes to skin inflammation in Para-Phenylenediamine-induced contact hypersensitivity.

Para-Phenylenediamine (PPD) is an aromatic amine used in hair dyes and in temporary black henna tattoos, which is a frequent cause of allergic contact dermatitis (ACD). ACD is a skin inflammatory reaction characterized by modifications such as spongiosis, exocytosis and acanthosis. The aim of this study is to characterize the expression and the role of IL-20-related cytokines, including IL-19, IL-20, IL-22 and IL-24, in ACD. The expression of IL19, IL20, IL22 and IL24 is increased in affected skin from PPD allergic patients compared with uninvolved skin. In addition, the expression of these cytokines positively correlates with clinical symptoms. To assess their role in ACD, we set up a mouse model of PPD-induced allergic contact dermatitis and we showed that, in contrast to Il22-deficient mice, Il22ra1-, Il20rb- and Il24-deficient mice are partially protected against development of PPD-induced contact hypersensitivity. These mice have decreased ear thickening and less acanthosis compared with WT mice after PPD treatment. In addition, the absence of IL-22R, IL-20R2 or IL-24 affects the recruitment of neutrophils into the skin but not the total IgE production. Taken together, these results demonstrate the implication of IL-24 via the IL-20R type II receptor in the inflammatory process of ACD.

Increased expression of interleukin-9 in patients with allergic contact dermatitis caused by p-phenylenediamine.

BACKGROUND: Allergic contact dermatitis has been described as a type IV reaction caused by antigen-specific T cells. Central roles for CD8+ cytotoxic T cells as effector cells and CD4+ T cells as regulatory cells have been suggested. T helper (Th) 2 and Th1 cytokines have been implicated; however, the nature of the allergen influences the Th response. OBJECTIVE: To determine the types of T cells and cytokines expressed in patients allergic to p-phenylenediamine (PPD). METHODS: Serial skin biopsies of areas with positive patch test reactions in 29 PPD-sensitized patients were collected. T cell markers and cytokine expression were analysed by flow cytometry and quantitative reverse transcription polymerase chain reaction in both skin and peripheral blood mononuclear cells (PBMCs) of sensitized patients. RESULTS: We observed increased expression of T cell markers and Th2/Th9-associated cytokines in both skin and stimulated PBMCs of PPD-allergic patients. Moreover, interleukin (IL)-9 was mainly produced by Th9 cells, in both skin and PBMCs. Further investigations showed that Il9r-deficient mice were more affected in a PPD contact hypersensitivity model than wild-type mice. CONCLUSION: We did not confirm the preclinical presence of CD8+ T cells. However, the expression of different T cell markers positively correlated with patch test reactions. IL-9 expression was strongly upregulated and directly related to patch test severity. In addition, we showed that IL-9 has an anti-inflammatory role in a mouse model of PPD contact hypersensitivity.

Prophylactic treatment against GM-CSF, but not IL-17, abolishes relapses in a chronic murine model of multiple sclerosis.

The pathogenic role of IL-17 and GM-CSF has been unravelled in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS). However, in most models, EAE is characterised by a monophasic attack which is not representative of the relapsing nature nor the chronicity displayed in MS. Here, we used proteolipid protein peptide (PLP139-151 ) to trigger EAE-relapses (EAE-II) in SJL mice that had recovered from a primary-EAE episode (EAE-I). This procedure resulted in severe and irreversible disease that, unlike EAE-I, was not abolished by anti-IL-17-mAb. In contrast, prophylactic anti-GM-CSF-mAb treatment prevented EAE-I and -II. Strikingly, the expression of T-cell transcription factors and cytokines/chemokines in mice treated with anti-GM-CSF during both EAE episodes was silenced. Anti-GM-CSF-mAb treatment administered only during EAE-II did not completely prevent relapses but mice ultimately reached full recovery. Anti-GM-CSF treatment also strongly impaired and ultimately resolved monophasic MOG35-55 -induced EAE in C57Bl/6 mice. In such protected mice, anti-GM-CSF treatment also prevented a further relapse induced by MOG-revaccination. These results underscore the critical role of GM-CSF on pro-inflammatory mediator production. Furthermore, we observed a strong preventive and curative effect of anti-GM-CSF neutralisation in two EAE models, relapsing and chronic. Altogether these findings are relevant for further MS research.

Novel highly specific anti-periostin antibodies uncover the functional importance of the fascilin 1-1 domain and highlight preferential expression of periostin in aggressive breast cancer.

Periostin (POSTN), a secreted homodimeric protein that binds integrins αvß3, αvß5, and α6ß4, was originally found to be expressed in fetal tissues and in the adult upon injury particularly bone fractures due to its role in remodelling and repair. Recently it was found to be over-expressed in human breast cancer and a variety of other tumour types including head and neck squamous cell carcinoma, where its overexpression correlates with increased tumour invasion. Progress in studying its functional role in tumour pathogenesis has been hampered by the paucity of antibodies for its specific and sensitive detection. It has proven very difficult to obtain monoclonal antibodies (mAbs) against this highly conserved protein but we report here that combining infection of mice with lactate dehydrogenase elevating virus (LDV), a B cell activating arterivirus, with conjugation of human POSTN to ovalbumin as an immunogenic carrier, enabled us to develop six mAbs recognizing both human and mouse POSTN and inhibiting its binding to αvß3 integrin. Two of the mAbs, MPB4B1 and MPC5B4, were tested and found to inhibit POSTN-induced migration of human endothelial colony forming cells. All six mAbs recognized amino acids 136-51 (APSNEAWDNLDSDIRR) within the POSTN fascilin (FAS) 1-1 domain revealing the functional importance of this motif; this was further highlighted by the ability of aa 136-151 peptide to inhibit integrin-mediated cell migration. Immunohistochemistry using MPC5B4, indicated that breast tumour cell POSTN expression was a strong prognostic indicator, along with tumour size, lymph node, and human epidermal growth factor receptor 2 (HER2) status.