NFAT1 transcription factor is central in the regulation of tissue microenvironment for tumor metastasis

Members of the nuclear factor of activated T cell (NFAT) family of transcription factors were originally described in T lymphocytes but later shown to be expressed in several immune and non-immune cell types. NFAT proteins can modulate cellular transformation intrinsically, and NFAT-deficient (NFAT1-/-) mice are indeed more susceptible to transformation than wild-type counterparts. However, the contribution of an NFAT1-/- microenvironment to tumor progression has not been studied. We have addressed this question by inoculating NFAT1-/- mice with B16F10 melanoma cells intravenously, an established model of tumor homing and growth. Surprisingly, NFAT1-/- animals sustained less tumor growth in the lungs after melanoma inoculation than wild-type counterparts. Even though melanoma cells equally colonize NFAT1-/- and wild-type lungs, tumors do not progress in the absence of NFAT1 expression. A massive mononuclear perivascular infiltrate and reduced expression of TGF-beta in the absence of NFAT1 suggested a role for tumor-infiltrating immune cells and the cytokine milieu. However, these processes are independent of an IL-4-induced regulatory tumor microenvironment, since lack of this cytokine does not alter the phenotype in NFAT1-/- animals. Bone marrow chimera experiments meant to differentiate the contributions of stromal and infiltrating cells to tumor progression demonstrated that NFAT1-induced susceptibility to pulmonary tumor growth depends on NFAT1-expressing parenchyma rather than on bone marrow-derived cells. These results suggest an important role for NFAT1 in radio-resistant tumor-associated parenchyma, which is independent of the anti-tumor immune response and Th1 versus Th2 cytokine milieu established by the cancer cells, but able to promote site-specific tumor growth.

Endostatin- and interleukin-2-expressing retroviral bicistronic vector for gene therapy of metastatic renal cell carcinoma

Background Metastatic renal cell carcinoma (mRCC) is one of the most treatment-resistant malignancies. Despite all new therapeutic advances, almost all patients develop resistance to treatment and cure is rarely seen. In the present study, we evaluated the antitumor effect of a bicistronic retrovirus vector encoding both endostatin (ES) and interleukin (IL)-2 using an orthotopic metastatic RCC mouse model. Methods Balb/C-bearing Renca cells were treated with NIH/3T3-LendIRES-IL-2-SN cells. In the survival studies, mice were monitored daily until they died. At the end of the in vivo experiment, serum levels of IL-2 and ES were measured, the lung was weighed, and the number of metastatic nodules, nodule area, tumor vessels and proliferation of tumor-infiltrating Renca cells were determined. Results Inoculation of NIH/3T3-LendIRES-IL-2-SN cells resulted in an increase in ES and IL-2 levels in the treated group (p < 0.05). There was a significant decrease in lung wet weight, lung nodule area and tumor vessels in the treated group compared to the control group (p < 0.001). The proliferation of Renca cells in the bicistronic-treated group was significantly reduced compared to the control group (p < 0.05). Kaplan-Meier survival curves showed that the probability of survival was significantly higher for mice submitted to bicistronic therapy (log-rank test, p = 0.0016). Bicistronic therapy caused an increase in the infiltration of CD4, CD4 interferon (IFN)gamma-producing, CD8, CD8 IFN gamma-producing and natural killer (CD49b) cells. Conclusions Retroviral bicistronic gene transfer led to the secretion of functional ES and IL-2 that was sufficiently active to: (i) inhibit tumor angiogenesis and tumor cell proliferation and (ii) increase the infiltration of immune cells (C) Copyright. 2011 John Wiley & Sons, Ltd.

Decrease in Mycobacterium tuberculosis specific immune responses in patients with untreated psoriasis living in a tuberculosis endemic area

Tuberculosis has emerged as a major concern in patients with immuno-mediated diseases, including psoriasis, undergoing treatment with biologicals. However, it is not known whether the chronically activated immune system of psoriasis patients interferes with their Mycobacterium tuberculosis (Mtb)-specific immunity, especially in tuberculosis-endemic areas like Brazil. We evaluated T-cell responses to a Mtb lysate and to the recombinant Mtb proteins ESAT-6 and Ag85B of tuberculin skin test (TST) positive and TST negative patients with severe or mild/moderate, untreated psoriasis in three different assays: lymphocyte proliferation, enzyme immunoassay for interferon (IFN)-gamma and interleukin (IL)-10 production by peripheral blood mononuclear cells and overnight enzyme immunospot (ELISpot) for enumerating IFN-gamma-secreting cells. In our cohort, a low proportion (29%) of the severe psoriasis patients tested were TST-positive. IFN-gamma and IL-10 secretion and T-cell proliferation to Mtb antigens were reduced in TST-negative but not in TST-positive patients with severe psoriasis when compared to healthy controls with the same TST status. Similarly, severe psoriasis patients had decreased cytokine secretion and proliferative response to phytohemagglutinin. However, most psoriasis patients and healthy controls showed detectable numbers of IFN-gamma-secreting effector-memory T-cells in response to Mtb antigens by ELISpot. TST-negative, mild/moderate psoriasis patients had responses that were mostly intermediary between TST-negative controls and severe psoriasis patients. Thus, patients with severe psoriasis possess decreased anti-Mtb central memory T-cell responses, which may lead to false-negative results in the diagnosis of TB infection, but retain T-cell memory-effector activity against Mtb antigens. We hypothesize that the latter may confer some protection against tuberculosis reactivation.

An overview of the immunopathology of human paracoccidioidomycosis

We review here the advances in the understanding of the immunopathology of human paracoccidioidomycosis (PCM). Its investigation must take in account the intriguing natural history of the mycosis and its agent, providing clues to the mechanisms that lead to development of disease (unbalanced host-parasite relationship?) or to the clinically silent, chronic carrier state (balanced host-parasite relationship?), in exposed people living in endemic areas. Although the literature on this subject has progressed notably, the overall picture of what are the mechanisms of susceptibility or resistance continues to be fragmentary. Major advances were seen in the description of both the cytokines/chemokines associated to the different outcomes of the host-parasite interaction, and the fungus-monocyte/macrophage interaction, and cytokines released thereof by these cells. However, relatively few studies have attempted to modify, even in vitro, the patients` unbalanced immune reactivity. Consequently, the benefits of this improved knowledge did not yet reach clinical practice. Fortunately, the previous notion of the immune system as having two nearly independent arms, the innate and adaptive immunities, leaving a large gap between them, is now being overcome. Immunologists are now trying to dissect the connections between these two arms. This will certainly lead to more productive results. Current investigations should address the innate immunity events that trigger the IL-12/IFN-gamma axis and confer protection against PCM in those individuals living in endemic areas, who have been infected, but did not develop the mycosis.

Atopic dermatitis in adults: evaluation of peripheral blood mononuclear cells proliferation response to Staphylococcus aureus enterotoxins A and B and analysis of interleukin-18 secretion

Atopic dermatitis (AD) is a chronic, inflammatory skin disease with a high prevalence and complex pathogenesis. The skin of AD patients is usually colonized by Staphylococcus aureus (S. aureus); its exotoxins may trigger or enhance the cutaneous inflammation. Several mediators are related to the AD immune imbalance and interleukin-18 (IL-18), an inflammatory cytokine, may play a role in the atopic skin inflammation. To evaluate peripheral blood mononuclear cells (PBMC) proliferation response to staphylococcal enterotoxins A (SEA) and B (SEB) and the levels of IL-18 in adults with AD. Thirty-eight adult patients with AD and 33 healthy controls were analysed. PBMC were stimulated with SEA and SEB, phytohemaglutinin (PHA), pokeweed (PWM), tetanus toxoid (TT) and Candida albicans (CMA). IL-18 secretion from PBMC culture supernatants and sera were measured by ELISA. A significant inhibition of the PBMC proliferation response to SEA, PHA, TT and CMA of AD patients was detected (P <= 0.05). Furthermore, increased levels of IL-18 were detected both in sera and non-stimulated PBMC culture supernatants from AD patients (P <= 0.05). A decreased PBMC proliferation response to distinct antigens and mitogens (TT, CMA, SEA and PHA) in adults with AD suggest a compromised immune profile. IL-18 secretion from AD upon stimulation was similar from controls, which may indicate a diverse mechanism of skin inflammation maintained by Staphylococcus aureus. On the other hand, augmented IL-18 secretion from AD sera and non-stimulated cell culture may enhance the immune dysfunction observed in AD, leading to constant skin inflammation.

Alterations in Cytokine Profile and Dendritic Cells Subsets in Peripheral Blood of Rheumatoid Arthritis Patients before and after Biologic Therapy

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic joint inflammation and continuous immune cell infiltration in the synovium. These changes are linked to inflammatory cytokine release, leading to eventual destruction of cartilage and bone. During the last decade new therapeutic modalities have improved the prognosis, with the introduction of novel biological response modifiers including anti-TNF alpha CTLA4Ig and, more recently, anti-IL6. In the present study we looked at the immunological effects of these three forms of therapy. Serum, obtained from patients with RA was analyzed for TNF alpha, IL6, IL10, IFN gamma, and VEGF, and in parallel, circulating plasmacytoid and myeloid dendritic cells (DC) were enumerated before and after three infusions of the respective biological treatments. After treatment with anti-IL6, we found a significant reduction of IL6 and TNF alpha levels and the percentage of both DC subsets decreased. Although the results did not reach statistical significance for anti-TNF alpha treatment, similar trends were observed. Meanwhile, CTLA4Ig therapy led to the reduction IFN gamma levels only. None of the treatments modified significantly VEGF or IL10 levels. These findings may explain why patients with RA improve more rapidly on IL-6 therapy than with the other two modalities.

Histopathology of mast cells and cytokines during healing of human mucosal leishmaniasis

Mast cells (MCs) are associated with chronic inflammatory diseases. However, there is no study evaluating the importance of MCs in the mucosal leishmaniasis (ML). The aim of this study was to quantify the most important cytokines associated with mucosal leishmaniasis, before and after disease treatment, correlating with the healing. A cohort of 12 patients with ML was evaluated, and biopsies were taken before and after the treatment. A quantitative estimation of MCs and some cytokines was analysed by density of the labelled cells through immunohistochemistry. The MCs count in the tissue from patients with ML before treatment showed a mean of 29.3 +/- 37.9 cells/mm(2). The MCs count in patients with ML after healing decreased to 14.8 +/- 23.9 cells/mm(2). There was an inverse relation of MCs with IFN-gamma and IL-4 expression (r(2) = 29.4 and r(2) = 22.3 with P < 0.05). The expression of IL-10 and TNF-alpha was not related with MCs count. MCs decrease after treatment associated with decrease of IL-4 and IFN-gamma. The explanations of cytokine correlation are discussed in the article.

Methylprednisolone improves lung mechanics and reduces the inflammatory response in pulmonary but not in extrapulmonary mild acute lung injury in mice

Objective: Gorticosteroids have been proposed to be effective in modulating the inflammatory response and pulmonary tissue remodeling in acute lung injury (ALI). We hypothesized that steroid treatment might act differently in models of pulmonary (p) or extrapulmonary (exp) ALI with similar mechanical compromise. Design: Prospective, randomized, controlled experimental study. Setting: University research laboratory. Subjects: One hundred twenty-eight BALB/c mice (20-25 g). Interventions: Mice were divided into six groups. In control animals sterile saline solution was intratracheally (0.05 mL, Cp) or intraperitoneally (0.5 mL, Gexp) injected, whereas ALI animals received Escherichia coli lipopolysaccharide intratracheally (10 mu g, ALIp) or intraperitoneally (125 mu g, ALIexp). Six hours after lipopolysaccharide administration, ALIp and ALlexp animals were further randomized into subgroups receiving saline (0.1 mL intravenously) or methylprednisolone (2 mg/kg intravenously, Mp and Mexp, respectively). Measurements and Main Results: At 24 hrs, lung state elastance, resistive and viscoelastic pressures, lung morphometry, and collagen fiber content were similar in both ALI groups. KC, interieukin-6, and transforming growth factor (TGF)-beta levels in bronchoatveolar lavage fluid, as well as tumor necrosis factor (TNF)-alpha, migration inhibitory factor (MIF), interferon (IFN)-gamma, TGF-beta 1 and TGF-beta 2 messenger RNA expression in lung tissue were higher in ALIp than in ALIexp animals. Methylprednisolone attenuated mechanical and morphometric changes, cytokine levels, and TNF-alpha, MIF, IFN gamma, and TGF-beta 2 messenger RNA expression only in ALIp animals, but prevented any changes in collagen fiber content in both ALI groups. Conclusions. Methylprednisolone is effective to inhibit fibrogenesis independent of the etiology of ALI, but its ability to attenuate inflammatory responses and lung mechanical changes varies according to the cause of ALI.

Immunization of neonatal mice with LAMP/p55 HIV gag DNA elicits robust immune responses that last to adulthood

Successful T cell priming in early postnatal life that can generate effective long-lasting responses until adulthood is critical in HIV vaccination strategies because it prevents early sexual initiation and breastfeeding transmission of HIV. A chimeric DNA vaccine encoding p55 HIV gag associated with lysosome-associated membrane protein 1 (LAMP-1; which drives the antigen to the MIIC compartment), has been used to enhance cellular and humoral antigen-specific responses in adult mice and macaques. Herein, we investigated LAMP-1/gag vaccine immunogenicity in the neonatal period in mice and its ability to generate long-lasting effects. Neonatal vaccination with chimeric LAMP/gag generated stronger Gag-specific immune responses, as measured by the breadth of the Gag peptide-specific IFN-gamma, proliferative responsiveness, cytokine production and antibody production, all of which revealed activation of CD4+ T cells as well as the generation of a more robust CTL response compared to gag vaccine alone. To induce long-lived T and B cell memory responses, it was necessary to immunize neonates with the chimeric IAMP/gag DNA vaccine. The LAMP/gag DNA vaccine strategy could be particularly useful for generating an anti-HIV immune response in the early postnatal period capable of inducing long-term immunological memory. (C) 2010 Elsevier Inc. All rights reserved.

Histopathology, humoral and cellular immune response in the murine model of Leishmania (Viannia) shawi

Leishmania (Viannia) shawl was recently characterized and few studies concerning modifications in cellular and humoral immune responses in experimental leishmaniasis have been conducted. In this work, immunopathological changes induced by L. shawl in chronically infected BALB/c mice were investigated. Infected BALB/c mice developed increased lesion size associated with strong inflammatory infiltrate diffusely distributed in the dermis, with highly infected macrophages. The humoral immune response was predominantly directed toward the IgG1 isotype. The functional activity of CD4(+) and CD8(+) T cells showed significantly increased TNF-alpha mRNA levels associated with reduced IFN-gamma expression by CD4(+) T cells and the double negative (dn) CD4CD8 cell subset. High IL-4 levels expressed by CD8(+) T cells and dnCD4CD8 and TGF-beta by CD4(+) and CD8(+) T cells were detected, while IL-10 was highly expressed by all three cell subpopulations. Taken together, these results show an evident imbalance between TNF-alpha and IFN-gamma that is unfavorable to amastigote replication control. Furthermore, L. shawi seems to regulate different cell populations to express deactivating cytokines to avoid its own destruction. This study indicates BALB/c mice as a potentially good experimental model for further studies on American cutaneous leishmaniosis caused by L. shawi. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Exacerbation of Leishmania (Viannia) shawi infection in BALB/c mice after immunization with soluble antigen from amastigote forms

The present study aimed to evaluate the effects of immunization with soluble amastigote (AmaAg) and promastigote (ProAg) antigens from Leishmania (Viannia) shawi on the course of infection in BALB/c mice. After immunization with AmaAg, the challenged group showed greater lesion size and parasite load in the skin and lymph nodes, associated with diminished interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-gamma and nitrate levels in the supernatant of lymph node cell cultures, together with increases in transforming growth factor (TGF)-beta concentrations and humoral immune response. In contrast, immunization with ProAg led to smaller lesion size with reduced numbers of viable parasites in the skin. Protection was associated with increases in IL-12, IFN-gamma, TGF-beta and nitrates and decreases in IL-4 and IL-10 levels. Concerning humoral immune response, a significant reduction in anti-leishmania immunoglobulin G was verified in the ProAg-challenged group. Analysis of these results suggests that AmaAg induced a suppressive cellular immune response in mice, favouring the spread of infection, whereas ProAg induced partial protection associated with increased cellular immune response.

Oral tolerance reduces Th17 cells as well as the overall inflammation in the central nervous system of EAE mice

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory immune response directed against myelin antigens of the central nervous system. In its murine model, EAE, Th17 cells play an important role in disease pathogenesis. These cells can induce blood-brain barrier disruption and CNS immune cells activation, due to the capacity to secrete high levels of IL-17 and IL-22 in an IL-6 + TGF-beta dependent manner. Thus, using the oral tolerance model, by which 200 mu g of MOG 35-55 is given orally to C57BL/6 mice prior to immunization, we showed that the percentage of Th17 cells as well as IL-17 secretion is reduced both in the periphery and also in the CNS of orally tolerated animals. Altogether, our data corroborates with the pathogenic role of IL-17 and IFN-gamma in EAE, as its reduction after oral tolerance, leads to an overall reduction of pro-inflammatory cytokines, such as IL-1 alpha, IL-6, IL-9, IL-12p70 and the chemokines MIP-1 beta, RANTES, Eotaxin and KC in the CNS. It is noteworthy that this was associated to an increase in IL-10 levels. Thus, our data clearly show that disease suppression after oral tolerance induction, correlates with reduction in target organ inflammation, that may be caused by a reduced Th1/Th17 response. Crown Copyright (c) 2010 Published by Elsevier B.V. All rights reserved.

Oral lesions in lupus erythematosus-cytokines profiles of inflammatory infiltrate

Background: Lupus erythematosus (LE) is a chronic inflammatory disease. Presence of type 1 cytokines in cutaneous discoid lesions suggests that they may be critical for induction, development and maintenance of these manifestations. Type 2 cytokines in combination with local interferon gamma (INF-gamma) are thought to be related to the physiopathology of cutaneous LE. Cytokines profiles are still unknown in oral LE lesions. Materials and Methods: Expression of Th1 and Th2 cytokines (including IL-4, IL-5, IL-6, IL-10, IL-12, tumor necrosis factor alpha (TNF-alpha) and INF-gamma was investigated and compared in 29 biopsies of intra-oral (sun-protected) and labial lesions (sun-exposed) of LE using immunohistochemistry. Results: Inflammatory infiltrate of LE lesions was strongly positive for IFN-gamma (97%) and TNF-alpha (90%), both Th1 type cytokines. Interleukin-10, a Th2 cytokine was also strongly expressed. Other cytokines were only mildly positive. Cytokines patterns were similar in intra-oral (sun-covered) and labial (sun-exposed) LE lesions. Conclusions: Oral LE lesions are associated with both type 1 and type 2 cytokines, characterized by stronger expression of INF-gamma, TNF-alpha and IL-10. These findings suggest that although ultraviolet (UV) light is involved in the induction of LE lesions, mechanisms of lesions formation may be similar in sun-exposed as well as sun-covered areas.

Novel humanized anti-CD3 antibodies induce a predominantly immunoregulatory profile in human peripheral blood mononuclear cells

Strategies to minimize the immunogenicity and toxicity of murine anti-CD3 antibodies (e.g. OKT3) are of special interest for organ transplantation and for the treatment of autoimmune diseases. In the present work, we have developed two humanized anti-CD3 antibodies. These molecules were shown to bind to human CD3, though less efficiently, and display less mitogenic activity than CKT3. These results prompted us to investigate whether this reduced mitogenic potential was associated with the development of anti-inflammatory properties. Indeed, in peripheral blood mononuclear cells (PBMCs), the humanized antibody versions induced a predominantly anti-inflammatory cytokine profile, in contrast with the pro-inflammatory profile induced by OKT3. Neither OKT3 nor the humanized versions induced the expression of IL-4, IL-2 or TGF-beta. Both humanized antibodies induced significantly lower production of IFN-gamma and IL-5 and slightly higher production of IL-10 than OKT3. This immunomodulatory profile was most evident by the 80-fold higher ratio of IL-10/IFN-gamma production in PBMCs cultured in the presence of the humanized antibodies, compared to those stimulated with CKT3. Furthermore, these humanized anti-CD3 antibodies induced a late FOXP3 gene expression while OKT3 led to a more transient expression of FOXP3. Taken our results, we suggest that these humanized anti-CD3 antibodies may promote the development of T cells with immunoregulatory activity. (C) 2009 Elsevier B.V. All rights reserved.

Human visceral leishmaniasis expresses Th1 pattern in situ liver lesions

The architectural and infiltrate pattern of liver human visceral leishmaniasis (HVL) have been systematically classified as typical, fibrogenic or nodular. Despite this histopathological classification, the immune response based on cytokines and cellular phenotypes have never been performed. The aim of this study was to determine the immunophenotypic pattern and cytokine profile of the nodular involvement of the Liver in HVL. We evaluated nine cases of the nodular form of HVL. In situ immune response was studied through cytokine analysis and immunohistochemical study for phenotype markers: IL-1, IL-4, IL-1 0, TNF-alpha, IFN-gamma, CD4+ T cells, CD8+ T cells, CD20, CD68, CD57 and macrophage activation was determined by evaluation of iNOS activity. HVL seems to be related to a better immune response. Amastigotes were rarely found on liver sections. Leishmania antigen expression was also rare and located in the inflammatory nodules. The lower expression of IL-4 and IL-10, moderate expression of TNF-alpha and IFN-gamma demonstrate a panorama of Th1 phenotype. The increased expression of NK cells could help in sustaining this model of response. This pattern of immune response is probably responsible for improvement in the parasite`s clearance from liver tissue and it is a prognostic marker of human visceral leishmaniasis. (C) 2008 The British Infection Society. Published by Elsevier Ltd. All rights reserved.