The establishment of immune tolerance during Glioblastoma Multiforme (GBM) progression, is characterized by high levels expression of anti-inflammatory cytokines, which suppress the function of tumor assocciated myeloid cells, and the activation and expansion of tumor antigen specific T cells. However, the mechanisms underlying the failed anti-tumor immune response around the blood vessels during GBM, are poorly understood. The consequences of possible interactions between cancer cells and the perivascular compartment might affect the tumor growth. In this work we show for the first time that GBM cells induce immunomodulatory changes in pericytes in a cell interaction-dependent manner, acquiring an immunosuppresive function that possibly assists the evasion of the anti-tumor immune response and consequently participates in tumor growth promotion. Expression of high levels of anti-inflammatory cytokines was detected in vitro and in vivo in brain pericytes that interacted with GBM cells (GBC-PC). Furthermore, reduction of surface expression of co-stimulatory molecules and major histocompatibility complex molecules in GBC-PC correlated with a failure of antigen presentation to T cells and the acquisition of the ability to supress T cell responses. In vivo, orthotopic xenotransplant of human glioblastoma in an immunocompetent mouse model showed significant GBM cell proliferation and tumor growth after the establishment of interspecific immunotolerance that followed GMB interaction with pericytes.

This study demonstrates virucidal and broad-spectrum antiviral activities for β escin and AH. Besides, β-escin and AH modulate cytokine production depending on the stimuli (viral or non-viral) and the cell type under study.

Aesculus hippocastanum L. seed extract shows virucidal and antiviral activities against respiratory syncytial virus (RSV) and reduces lung inflammation in vivo

Meliacine (MA), an antiviral principle present in partially purified leaf extracts of Melia azedarach L., prevents the development of herpetic stromal keratitis (HSK) in mice by diminishing the viral load in the eye and the severity of lesions caused by a virus-induced immunopathological reaction. The tetranortriterpenoid 1-cinnamoyl-3,11-dihydroxymeliacarpin (CDM), obtained from MA purification, displays anti-herpetic activity and impedes nuclear factor kappaB (NF-kappaB) activation in HSV-1 infected conjunctival cells. To extend our understanding about CDM biological properties, we investigated its anti-HSV-1 activity as well as the effect on NF-kappaB activation and cytokine secretion induced by viral (HSV-1) and no-viral (LPS) stimuli, in corneal cells and macrophages. CDM exerted a potent anti-HSV-1 effect on corneal cells and inhibited NF-kappaB translocation to the nucleus, leading to a decrease in IL-6 production. Besides, CDM seemed to modulate IL-6 and TNF-alpha responses in macrophages, whether they were infected with HSV-1 or stimulated with LPS. However, CDM did not affect NF-kappaB activation in these cells, suggesting that an alternative NF-kappaB cell signaling pathway would be involved in the modulation of cytokine production. We conclude that, in addition to its antiviral effect, CDM would be acting as an immunomodulating compound which would be responsible for the improvement of murine HSK already reported.

The phytochemical investigation of the dichloromethane-soluble part of the methanol extract obtained from the fruits of Melia azedarach afforded one new tirucallane-type triterpene, 3-α-tigloylmelianol (1) and three known tirucallanes, melianone (2), 21-β-acetoxy-melianone (3), and methyl kulonate (4). The structure of the isolated compounds was mainly determined by 1D and 2D NMR experiments as well as HPLC-Q-TOF mass spectrometry. The cytotoxicity of the isolated compounds toward the human lung adenocarcinoma epithelial cell line A549 was determined, while no activity was observed against the phytonematode Meloidogyne incognita.

Cytomegalovirus (CMV) is an opportunistic virus severely infecting immunocompromised individuals. In mice, endosomal Toll-like receptor 9 (TLR9) and downstream myeloid differentiation factor 88 (MyD88) are central to activating innate immune responses against mouse CMV (MCMV). In this respect, the cell-specific contribution of these pathways in initiating anti-MCMV immunity remains unclear. Using transgenic mice, we demonstrate that TLR9/MyD88 signaling selectively in CD11c dendritic cells (DCs) strongly enhances MCMV clearance by boosting natural killer (NK) cell CD69 expression and IFN-γ production. In addition, we show that in the absence of plasmacytoid DCs (pDCs), conventional DCs (cDCs) promote robust NK cell effector function and MCMV clearance in a TLR9/MyD88-dependent manner. Simultaneously, cDC-derived IL-15 regulates NK cell degranulation by TLR9/MyD88-independent mechanisms. Overall, we compartmentalize the cellular contribution of TLR9 and MyD88 signaling in individual DC subsets and evaluate the mechanism by which cDCs control MCMV immunity.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease and bronchiolitis in children, as well as an important cause of morbidity and mortality in elderly and immunocompromised individuals. However, there is no safe and efficacious RSV vaccine or antiviral treatment. Toll Like Receptors (TLR) are important molecular mediators linking innate and adaptive immunity, and their stimulation by cognate agonists has been explored as antiviral agents. Imiquimod is known as a TLR7 agonist, but additionally acts as an antagonist for adenosine receptors. In this study, we demonstrate that imiquimod, but not resiquimod, has direct anti-RSV activity via PKA pathway in HEp-2 and A549 cells, independently of an innate response. Imiquimod restricts RSV infection after viral entry into the host cell, interfering with viral RNA and protein synthesis. Probably as a consequence of these anti-RSV properties, imiquimod displays cytokine modulating activity in RSV infected epithelial cells. Moreover, in a murine model of RSV infection, imiquimod treatment improves the course of acute disease, evidenced by decreased weight loss, reduced RSV lung titers, and attenuated airway inflammation. Consequently, imiquimod represents a promising therapeutic alternative against RSV infection and may inform the development of novel therapeutic targets to control RSV pathogenesis.

The pathogenesis of many viral infections lies on the damage caused by the immune response against the virus. Current antiviral drugs do not act on the inflammatory component of the disease. Thus, new compounds that inhibit both viral multiplication and the immunopathology elicited by the virus are an approach that should be considered. In the present study, we identified two jatropholones (2A and 5B) and one carnosic acid derivative (9C) that significantly inhibited multiplication of TK+ and TK- strains of HSV-1 in Vero cells. Compounds 2A, 5B and 9C also prevented HSV-1- and TLRs-induced inflammatory response in cultivated murine macrophages. In macrophages infected with HSV-1, the inhibitory effect of compounds 2A, 5B and 9C on TNF-α and IL-6 production could be associated with the block of ERK pathway, whereas NF-κB pathway was not hampered by any of the compounds. Besides, 2A, 5B and 9C also inhibited ERK pathway and reduced TNF-α production in macrophages stimulated with TLR2, TLR4 or TLR9 agonists and were able to hinder IL-6 secretion after activation with TLR2 or TLR4, but not with TLR9. The immunomodulatory effect of 2A, 5B and 9C in macrophages infected with HSV-1 may be a consequence of the inhibition of ERK pathway activated by TLRs. The availability of compounds with both antiviral and immunomodulatory properties which affect TLR signaling pathways might be a useful strategy to control the progress of virus-induced disease.