Macrophage Migration Inhibitory Factor (MIF) Promotes Increased Proportions of the Highly Permissive Th17-like Cell Profile during HIV Infection.

In this study, we evaluate the role of the MIF/CD74 axis in the functionality of CD4+ T lymphocytes (CD4TL) during HIV infection. MDMs from healthy donors were infected with a R5-tropic or Transmitted/Founder (T/F) HIV strain. At day 11 post-MDM infection, allogeneic co-cultures with uninfected CD4TLs plus MIF stimulus were performed. Cytokine production was evaluated by ELISA. MIF plasma levels of people with HIV (PWH) were evaluated by ELISA. The phenotype and infection rate of CD4TLs from PWH were analyzed after MIF stimulus. Intracellular cytokines and transcription factors were evaluated by flow cytometry. Data were analyzed by parametric or non-parametric methods. The MIF stimulation of HIV-infected MDMs induced an increased expression of IL-6, IL-1ß and IL-8. In CD4TL/MDM co-cultures, the MIF treatment increased IL-17A/RORγt-expressing CD4TLs. Higher concentrations of IL-17A in supernatants were also observed. These results were recapitulated using transmitted/founder (T/F) HIV-1 strains. The MIF treatment appeared to affect memory CD4TLs more than naïve CD4TLs. MIF blocking showed a negative impact on IL17A+CD4TL proportions. Higher MIF concentrations in PWH-derived plasma were correlated with higher IL-17A+CD4TL percentages. Finally, MIF stimulation in PWH-derived PBMCs led to an increase in Th17-like population. MIF may contribute to viral pathogenesis by generating a microenvironment enriched in activating mediators and Th17-like CD4TLs, which are known to be highly susceptible to HIV-1 infection and relevant to viral persistence. These observations establish a basis for considering MIF as a possible therapeutic target.

M1 Macrophage Polarization Prevails in Epstein-Barr Virus-Infected Children in an Immunoregulatory Environment.

Macrophages can be polarized toward a proinflammatory phenotype (M1) (CD68+) or to an anti-inflammatory one (M2) (CD163+). Polarization can be triggered by cytokines such as IFN-γ for M1, or IL-10 and TGF-ß, for M2. In the context of pediatric Epstein Barr virus (EBV) infection, little is known about macrophage polarization in EBV primary or persistent infection. When studying tonsils of patients undergoing primary infection (PI), healthy carrier (HC), reactivation (R), and not infected (NI), M1 profile prevailed in all infection status. However, an increase in M2 cells was observed in those patients with broader expression of latency antigens, in particular EBNA2. Tonsils from primary infected patients showed an increased IL-10 expression, whereas, unexpectedly, TGF-ß expression correlated with M1 marker. Furthermore, an inverse correlation was demonstrated between CD68 and IFN-γ. Therefore, in the context of asymptomatic infection in children, M1 macrophage polarization prevails, even in the presence of IL-10 and TGF-Ꞵ immunomodulatory cytokines, and it might be independent from lymphomagenesis process. Our finding indicates that macrophages may have a significant plasticity in response to different types of extrinsic stimuli, and further studies are required to investigate M1 polarization under anti-inflammatory stimuli. IMPORTANCE Most studies on Epstein Barr virus (EBV) primary infection have been performed in adolescents and young adult populations with Infectious Mononucleosis (IM) in developed countries. Furthermore, studies related to macrophage polarization were assessed in EBV-associated lymphomas, but little is known about macrophage polarization in the context of primary infection at the site of viral entry and replication, the tonsils. Therefore, the aim of this study was to characterize macrophage response in children undergoing EBV primary or persistent infection, in order to enlighten the role of macrophages in viral pathogenesis, in a population with a high incidence of EBV-associated lymphomas in children younger than 10 years old. This study may contribute to explain, at least in part, the asymptomatic viral infection in children from an underdeveloped region, given that M1 polarization pattern prevails, but in a regulatory environment.

Highly Purified Alloantigen-Specific Tregs From Healthy and Chronic Kidney Disease Patients Can Be Long-Term Expanded, Maintaining a Suppressive Phenotype and Function in the Presence of Inflammatory Cytokines.

The adoptive transfer of alloantigen-specific regulatory T cells (alloTregs) has been proposed as a therapeutic alternative in kidney transplant recipients to the use of lifelong immunosuppressive drugs that cause serious side effects. However, the clinical application of alloTregs has been limited due to their low frequency in peripheral blood and the scarce development of efficient protocols to ensure their purity, expansion, and stability. Here, we describe a new experimental protocol that allows the long-term expansion of highly purified allospecific natural Tregs (nTregs) from both healthy controls and chronic kidney disease (CKD) patients, which maintain their phenotype and suppressive function under inflammatory conditions. Firstly, we co-cultured CellTrace Violet (CTV)-labeled Tregs from CKD patients or healthy individuals with allogeneic monocyte-derived dendritic cells in the presence of interleukin 2 (IL-2) and retinoic acid. Then, proliferating CD4+CD25hiCTV- Tregs (allospecific) were sorted by fluorescence-activated cell sorting (FACS) and polyclonally expanded with anti-CD3/CD28-coated beads in the presence of transforming growth factor beta (TGF-ß), IL-2, and rapamycin. After 4 weeks, alloTregs were expanded up to 2,300 times the initial numbers with a purity of >95% (CD4+CD25hiFOXP3+). The resulting allospecific Tregs showed high expressions of CTLA-4, LAG-3, and CD39, indicative of a highly suppressive phenotype. Accordingly, expanded alloTregs efficiently suppressed T-cell proliferation in an antigen-specific manner, even in the presence of inflammatory cytokines (IFN-γ, IL-4, IL-6, or TNF-α). Unexpectedly, the long-term expansion resulted in an increased methylation of the specific demethylated region of Foxp3. Interestingly, alloTregs from both normal individuals and CKD patients maintained their immunosuppressive phenotype and function after being expanded for two additional weeks under an inflammatory microenvironment. Finally, phenotypic and functional evaluation of cryopreserved alloTregs demonstrated the feasibility of long-term storage and supports the potential use of this cellular product for personalized Treg therapy in transplanted patients.

CAR-T Cells for Cancer Treatment: Current Design and Next Frontiers.

Immunotherapy has been growing in the past decade as a therapeutic alternative for cancer treatment. In this chapter, we deal with CAR-T cells, genetically engineered autologous T cells to express a chimeric receptor specific for an antigen expressed on tumor cell surface. While this type of personalized therapy is revolutionizing cancer treatment, especially B cell malignancies, it has some challenging limitations. Here, we discuss the basic immunological and technological aspects of CAR-T cell therapy, the limitations that have compromised its efficacy and safety, and the current proposed strategies to overcome these limitations, thereby allowing for greater therapeutic application of CAR-T cells.

Staphylococcus epidermidis role in the skin microenvironment.

Wound healing is a complex dynamic physiological process in response to cutaneous destructive stimuli that aims to restore the cutaneous' barrier role. Deciphering the underlying mechanistic details that contribute to wound healing will create novel therapeutic strategies for skin repair. Recently, by using state-of-the-art technologies, it was revealed that the cutaneous microbiota interact with skin immune cells. Strikingly, commensal Staphylococcus epidermidis-induced CD8+ T cells induce re-epithelization of the skin after injury, accelerating wound closure. From a drug development perspective, the microbiota may provide new therapeutic candidate molecules to accelerate skin healing. Here, we summarize and evaluate recent advances in the understanding of the microbiota in the skin microenvironment.

Unveiling the Link Between Inflammation and Adaptive Immunity in Breast Cancer.

Inflammation has been recognized as an important driver in the development and growth of malignancies. Inflammatory signaling in cancer emerges from the combinatorial interaction of several deregulated pathways. Pathway deregulation is often driven by changes in the underlying gene regulatory networks. Confronted with such complex scenario, it can be argued that a closer analysis of the structure of such regulatory networks will shed some light on how gene deregulation led to sustained inflammation in cancer. Here, we inferred an inflammation-associated gene regulatory network from 641 breast cancer and 78 healthy samples. A modular structure analysis of the regulatory network was carried out, revealing a hierarchical modular structure. Modules show significant overrepresentation score p-values for biological processes unveiling a definite association between inflammatory processes and adaptive immunity. Other modules are enriched for T-cell activation, differentiation of CD8+ lymphocytes and immune cell migration, thus reinforcing the aforementioned association. These analyses suggest that in breast cancer tumors, the balance between antitumor response and immune tolerance involving CD8+ T cells is tipped in favor of the tumor. One possible mechanism is the induction of tolerance and anergization of these cells by persistent antigen exposure.

Th17/Treg imbalance in COPD progression: A temporal analysis using a CS-induced model.

BACKGROUND: The imbalance between pro- and anti-inflammatory immune responses plays a pivotal role in chronic obstructive pulmonary disease (COPD) development and progression. To clarify the pathophysiological mechanisms of this disease, we performed a temporal analysis of immune response-mediated inflammatory progression in a cigarette smoke (CS)-induced mouse model with a focus on the balance between Th17 and Treg responses. METHODS: C57BL/6 mice were exposed to CS for 1, 3 or 6 months to induce COPD, and the control groups were maintained under filtered air conditions for the same time intervals. We then performed functional (respiratory mechanics) and structural (alveolar enlargement) analyses. We also quantified the NF-κB, TNF-α, CD4, CD8, CD20, IL-17, IL-6, FOXP3, IL-10, or TGF-ß positive cells in peribronchovascular areas and assessed FOXP3 and IL-10 expression through double-label immunofluorescence. Additionally, we evaluated the gene expression of NF-κB and TNF in bronchiolar epithelial cells. RESULTS: Our CS-induced COPD model exhibited an increased proinflammatory immune response (increased expression of the NF-κB, TNF-α, CD4, CD8, CD20, IL-17, and IL-6 markers) with a concomitantly decreased anti-inflammatory immune response (FOXP3, IL-10, and TGF-ß markers) compared with the control mice. These changes in the immune responses were associated with increased alveolar enlargement and impaired lung function starting on the first month and third month of CS exposure, respectively, compared with the control mice. CONCLUSION: Our results showed that the microenvironmental stimuli produced by the release of cytokines during COPD progression lead to a Th17/Treg imbalance.

Probiotics alter the immune response of gingival epithelial cells challenged by Porphyromonas gingivalis.

BACKGROUND AND OBJECTIVE: Although previous studies revealed the potential use of probiotics in the control of periodontitis, little is known about their interactions with gingival epithelial cells (GECs). Since GECs comprise the first defense in the subgingival microenvironment, the aim of this study was to evaluate the effect of probiotic lactobacilli and bifidobacteria strains on OBA-9 cells challenged with Porphyromonas gingivalis. METHODS: Immortalized human GECs (OBA-9) were challenged with live P. gingivalis (strains W83 and ATCC33277) and co-infected with one of 12 tested probiotic strains at a multiplicity of infection (MOI) of 1:1000 for 2 hours. Bacterial adhesion and invasion were determined by antibiotic exclusion analysis and CFU counting. OBA-9 viability was assessed by MTT assay, and levels of inflammatory mediators (TNF-α, IL-1ß, and CXCL8) in the supernatants were determined by ELISA. The expression of genes encoding Toll-like receptors (TLR2, TLR4) was evaluated by RT-qPCR. RESULTS: Both strains of P. gingivalis were able to adhere and invade OBA-9 cells, with significant loss in cell viability, increase in the levels of TNF-α and IL-1ß, and upregulation of TLR4. However, co-infection with probiotics attenuated these effects in P. gingivalis challenged GECs. Most probiotics maintained OBA-9 viability and reduced pathogens adhesion and invasion. Furthermore, probiotics were able to adhere to GECs, which was enhanced for most strains in the presence of P. gingivalis. The synthesis of IL-1ß and TNF-α by P. gingivalis in challenged GECs was reduced in co-culture with most of the tested probiotics, whereas the secretion of CXCL8 increased, and TLR4 was downregulated. CONCLUSION: Probiotics can alter the interaction of GECs with P. gingivalis by modulating the pathogen's ability to adhere and invade these cells, as well as by regulating the innate immune response. Such properties are strain-specific and may indicate the most efficient probiotics to control periodontitis.

Macrophage roles in the clearance of apoptotic cells and control of inflammation in the prostate gland after castration.

BACKGROUND: Androgen deprivation results in massive apoptosis in the prostate gland. Macrophages are actively engaged in phagocytosing epithelial cell corpses. However, it is unknown whether microtubule-associated protein 1 light chain 3 alpha (LC3)-associated phagocytosis (LAP) is involved and contribute to prevent inflammation. METHODS: Flow cytometry, RT-PCR and immunohistochemistry were used to characterize the macrophage subpopulation residing in the epithelial layer of the rat ventral prostate (VP) after castration. Stereology was employed to determine variations in the number of ED1 and ED2. Mice were treated with either chloroquine or L-asparagine to block autophagy. RESULTS: M1 (iNOS-positive) and M2 macrophages (MRC1+ and ARG1+) were not found in the epithelium at day 5 after castration. The percentage of CD68+ (ED1) and CD163+ (ED2) phenotypes increased after castration but only CD68+ cells were present in the epithelium. RT-PCR showed increased content of the autophagy markers Bcl1 and LC3 after castration. In addition, immunohistochemistry showed the presence of LC3+ and ATG5+ cells in the epithelium. Double immunohistochemistry showed these cells to be CD68+ /LC3+ , compatible with the LAP phenotype. LC3+ cells accumulate significantly after castration. Chloroquine and L-asparagine administration caused inflammation of the glands at day 5 after castration. CONCLUSIONS: CD68+ macrophages phagocytose apoptotic cell corpses and activate the LAP pathway, thereby contributing to the preservation of a non-inflammed microenvironment. Marked inflammation was detected when autophagy blockers were administered to castrated animals.

Chronic hepatitis C liver microenvironment: role of the Th17/Treg interplay related to fibrogenesis.

The role of the different lymphocyte populations in liver microenvironment of chronic hepatitis C (CHC) patients is still matter of debate. Since Th17 and Treg have opposite functions, their balance could affect disease progression. The aim was to explore liver microenvironment and its peripheral blood counterpart in adult CHC patients. CD4+ lymphocytes were predominant in the liver, with high Foxp3+ but low IL-17A+ frequency. IL-17A+ lymphocytes and IL-17A+/Foxp3+ ratio displayed association with advanced fibrosis (p = 0.0130; p = 0.0236, respectively), while Foxp3+ lymphocytes and IL-10 expression level inversely correlated with fibrosis severity (p = 0.0381, p = 0.0398, respectively). TGF-ß/IL-6 ratio correlated with IL-17A+/Foxp3+ ratio (p = 0.0036, r = 0.5944) and with IL-17A+ lymphocytes (p = 0.0093; r = 0.5203). TNF-α and TGF-ß were associated with hepatitis severity (p = 0.0409, p = 0.0321). Peripheral blood lymphocyte frequency was not associated with liver damage. There are functionally different immune cell populations actively involved in liver damage, but the liver cytokine milieu actually drives the pathogenesis. The intrahepatic Foxp3+ lymphocytes predominance beside the low IL-17A+ lymphocytes frequency, delineate a skewed IL-17A+/Foxp3+ balance towards Foxp3+ lymphocytes. However, the IL-17A+ lymphocytes association with advanced fibrosis denotes their role in the pathogenesis. Therefore, the interplay between Th17 and Treg conditions liver fibrogenesis.

De novo AML exhibits greater microenvironment dysregulation compared to AML with myelodysplasia-related changes.

The interaction between the bone marrow microenvironment and malignant hematopoietic cells can result in the protection of leukemia cells from chemotherapy in both myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). We, herein, characterized the changes in cytokine expression and the function of mesenchymal stromal cells (MSC) in patients with MDS, AML with myelodysplasia-related changes (MRC), a well-recognized clinical subtype of secondary AML, and de novo AML. We observed a significant inhibitory effect of MDS-MSC on T lymphocyte proliferation and no significant differences in any of the cytokines tested. AML-MSC inhibited T-cell proliferation only at a very low MSC/T cell ratio. When compared to the control, AML-MRCderived MSC presented a significant increase in IL6 expression, whereas de novo AML MSC presented a significant increase in the expression levels of VEGFA, CXCL12, RPGE2, IDO, IL1ß, IL6 and IL32, followed by a decrease in IL10 expression. Furthermore, data indicate that IL-32 regulates stromal cell proliferation, has a chemotactic potential and participates in stromal cell crosstalk with leukemia cells, which could result in chemoresistance. Our results suggest that the differences between AML-MRC and de novo AML also extend into the leukemic stem cell niche and that IL-32 can participate in the regulation of the bone marrow cytokine milieu.

High levels of CXC ligand 12/stromal cell-derived factor 1 in apical lesions of endodontic origin associated with mast cell infiltration.

INTRODUCTION: CXC ligand 12/stromal-derived factor-1 (CXCL12/SDF-1) is a pleiotropic chemokine that regulates the influx of a wide range of leukocytes. The aim of this study was to characterize CXCL12/SDF-1 in apical lesions (ALs) of endodontic origin, with special emphasis in associated immune cell populations. METHODS: In this case-control study, 29 individuals with chronic apical periodontitis and 21 healthy volunteers were enrolled. ALs and healthy periodontal ligament samples were obtained for tissue homogenization, immune Western blotting, and enzyme-linked immunosorbent assay to determine CXCL12/SDF-1 forms and levels. Anatomopathologic diagnosis, immunostaining for CXCL12/SDF-1, CD117-CXCL12/SDF-1, and toluidine blue were also performed to identify tissue and cell localization. Finally, a set of tissue samples were digested and analyzed by flow cytometry to identify CXCL12/SDF-1 in different immune cell populations. Data were analyzed with Stata v11 and WinDi 2.9 software, and significance was considered if P < .05. RESULTS: CXCL12/SDF-1 was predominantly identified as monomers; levels of CXCL12/SDF-1 were significantly higher in ALs compared with controls, and it was primarily localized to inflammatory infiltrates. Expression of CXCL12/SDF-1 was colocalized to mast cells in tissue sections. Furthermore, CD117(+) mast cells were the second most frequent infiltrating cells and the main CXCL12/SDF-1 expressing cells, followed by CD4(+) lymphocytes, monocytes/macrophages, neutrophils, and dendritic cells. CONCLUSIONS: ALs of endodontic origin demonstrated higher levels of CXCL12/SDF-1 compared with controls. CXCL12/SDF-1 was identified in immune cell populations, whereas mast cells represented the major CXCL12/SDF-1 expressing cells, suggesting that this chemokine might play a central role in apical tissue destruction, most probably inducing persistent recruitment of immune cells, particularly of mast cells.

Increased leptin response and inhibition of apoptosis in thymocytes of young rats offspring from protein deprived dams during lactation.

We investigated the consequences of mild maternal malnutrition in rat dams, in terms of thymocyte responses and the putative role of leptin. The young progeny of dams submitted to protein deprivation (PD) during lactation showed at 30 days of age lower body and thymus weights, significant alterations in CD4/CD8-defined T cell subsets without modifications in total thymocyte number as well as in proliferative response. Despite, the rats from PD group did not present alterations in leptin circulating levels, the expression of leptin receptor ObRb was enhanced in their thymocytes. This change was accompanied by an increase in leptin signaling response of thymocytes from PD rats, with an increase in JAK2 and STAT3 phosphorylation after leptin stimulation. Thymocytes from PD rats also presented a decreased rate of spontaneous apoptosis when compared to controls. Accordingly, higher expression of anti-apoptotic protein Bcl-2, and lower of pro-apoptotic protein Bax, with no change of pro-apoptotic Bad, and higher pro-caspase 3 content were detected in PD thymocytes. Moreover, thymocytes from PD group exhibited a constitutive higher nuclear content of p65 NF-kB associated to a lower IkB content in the cytoplasm. Finally, although there was no change in ob gene expression in PD thymocytes, a higher mRNA expression for the Ob gene was observed in the thymic microenvironment from PD animals. Taken together, the results show that mild maternal protein deprivation during lactation affects thymic homeostasis, enhancing leptin activity, which in turn protects thymocytes from apoptosis in the young progeny, with possible consequences upon the immune response of these animals in adult life.

Anti-inflammatory/regulatory cytokine microenvironment mediated by IL-4 and IL-10 coordinates the immune response in hemophilia A patients infected chronically with hepatitis C virus.

In the past decades patients with hemophilia were infected commonly by hepatitis C virus (HCV) and a significant number of patients are infected chronically. Focusing on the role of the immune system for controlling and or maintaining HCV infection, the leukocyte and cytokine profiles of peripheral blood from hemophilia A patients and other patients with and without HCV infection were studied. The results demonstrated that hemophilia A is characterized by a general state of circulating leukocytes activation along with an overall increase in the frequency of IL-6 and IL-10 with decrease of IL-8 and IL-12. HCV infection of patients with hemophilia A does not influence further the activation state of circulating leukocytes but is accompanied by lower levels of alanine transaminase (ALT) and a prominent anti-inflammatory/regulatory serum cytokine pattern, mediated by IL-4 and IL-10. Additionally, the results demonstrated that hemophilia A patients infected with HCV displaying No/Low antibody response to C33c and C22 have significant lower viral load and higher serum levels of IL-12 and IL-4. This finding suggests that the differential RIBA reactivity to C33c/C22 HCV core proteins may have a putative value as a prognostic biomarker for the infection in hemophilia A patients.

Bayesian approach to model CD137 signaling in human M. tuberculosis in vitro responses.

Immune responses are qualitatively and quantitatively influenced by a complex network of receptor-ligand interactions. Among them, the CD137:CD137L pathway is known to modulate innate and adaptive human responses against Mycobacterium tuberculosis. However, the underlying mechanisms of this regulation remain unclear. In this work, we developed a Bayesian Computational Model (BCM) of in vitro CD137 signaling, devised to fit previously gathered experimental data. The BCM is fed with the data and the prior distribution of the model parameters and it returns their posterior distribution and the model evidence, which allows comparing alternative signaling mechanisms. The BCM uses a coupled system of non-linear differential equations to describe the dynamics of Antigen Presenting Cells, Natural Killer and T Cells together with the interpheron (IFN)-γ and tumor necrosis factor (TNF)-α levels in the media culture. Fast and complete mixing of the media is assumed. The prior distribution of the parameters that describe the dynamics of the immunological response was obtained from the literature and theoretical considerations Our BCM applies successively the Levenberg-Marquardt algorithm to find the maximum a posteriori likelihood (MAP); the Metropolis Markov Chain Monte Carlo method to approximate the posterior distribution of the parameters and Thermodynamic Integration to calculate the evidence of alternative hypothesis. Bayes factors provided decisive evidence favoring direct CD137 signaling on T cells. Moreover, the posterior distribution of the parameters that describe the CD137 signaling showed that the regulation of IFN-γ levels is based more on T cells survival than on direct induction. Furthermore, the mechanisms that account for the effect of CD137 signaling on TNF-α production were based on a decrease of TNF-α production by APC and, perhaps, on the increase in APC apoptosis. BCM proved to be a useful tool to gain insight on the mechanisms of CD137 signaling during human response against Mycobacterium tuberculosis.

Human myeloid dendritic cells treated with supernatants of rotavirus infected Caco-2 cells induce a poor Th1 response.

We have previously shown that human myeloid dendritic cells treated with purified rotavirus induce an allogenic Th1 response. To determine if rotavirus in the context of an intestinal microenvironment modulates the function of dendritic cells, we treated these cells with supernatants from non-infected or infected Caco-2 cells and studied their capacity to promote Th1 or Th2 responses. Dendritic cells treated with supernatants from rotavirus-infected Caco-2 cells promoted a significantly lower Th1 response, in comparison with those treated with purified rotavirus. We wanted to establish if TGF-ß1, induced, or TSLP, not induced, during rotavirus infection, could mediate this effect. Neutralization of TGF-ß but not TSLP in the supernatant prior to treatment of dendritic cells increased their capacity to promote a Th1 response. The results suggest that the TGF-ß1 induced by rotavirus could be an immune evasion mechanism, and may partially explain the poor rotavirus-specific T cell response we have previously evidenced.

Nattectin a fish C-type lectin drives Th1 responses in vivo: licenses macrophages to differentiate into cells exhibiting typical DC function.

Considerable efforts are currently focused on the biology of DC in view of their possible clinical use as adjuvant for the generation of antigen-specific immunity and lifelong immunologic memory or for the treatment of tumors. We assessed the role of Nattectin a C-type lectin identified in the Thalassophryne nattereri fish venom in DC maturation. Nattectin induced a significant neutrophilic recruitment into peritoneal cavity of mice, followed by macrophages, with lipidic mediators and IL-12 p70 synthesis. Macrophages derived from 7day-Nattectin mice were CD11c+CD11b(low)Ly6(high)F4/80R(high) and express high levels of MHC class II and CD80 molecules. Culture of peritoneal exudates derived macrophages from 7day Nattectin-mice and immature BMDCs with Nattectin markedly increased the surface expression of CD40, CD80, CD86, and MHC class II in a dose-dependent manner, and the production of MMP-2 and MMP-9 distributed in nucleus and cytoplasm of cells, that was associated with strong activity in the culture supernatant. Nattectin treated DCs secreted IL-12 p70 and IL-10. The Nattectin-treated BMDC or macrophage-derived DCs were highly efficient at Ag capture. The specific immune response elicited by Nattectin was characterized by the production of specific antibodies IgG1 and mainly IgG2a with IL-10 and IFN-γ synthesis by splenic cells. These results enable us to address that Nattectin induces the recruitment of Ly6C(high) monocytes into the peritoneum, which exhibit a pro-inflammatory profile, where they differentiate into proliferating F4/80R(high) macrophages. Macrophage-derived DCs mature in the presence of the cytokine milieu generated against Nattectin, exhibiting T cell co-stimulatory molecule expression and induced a Th1 polarized response.

Toll-like receptors are key players in neurodegeneration.

The activation of innate immune response is initiated by engagement of pattern-recognition receptors (PPRs), such as Toll-like receptors (TLRs). These receptors are expressed in peripheral leukocytes and in many cell types in the central nervous system (CNS). The expression of TLRs in CNS was mainly studied in astrocytes and microglial cells. However, new evidence indicates that these receptors may play an important role in neuronal homeostasis. The expression of TLRs in the CNS is variable and can be modulated by multiple factors, including pro-inflammatory molecules, which are elevated in neurodegenerative diseases and can increase the expression of TLRs in CNS cells. Moreover, activation of TLRs induces the release of pro-inflammatory cytokines. Therefore, TLRs have been shown to play a role in several aspects of neurodegenerative diseases. Here we will discuss results reported in the recent literature concerning the participation of TLRs in neurodegenerative diseases.