Dendritic cell are able to differentially recognize Sporothrix schenckii antigens and promote Th1/Th17 response in vitro.

Sporotrichosis is a disease caused by the dimorphic fungus Sporothrix schenckii. The main clinical manifestations occur in the skin, however the number of systemic and visceral cases has increased, especially in immunocompromised patients. Dendritic cells (DCs) are highly capable to recognize the fungus associated data and translate it into differential T cells responses both in vivo and in vitro. Although, the mechanisms involved in the interaction between DCs and S. schenckii are not fully elucidated. The present study investigated the phenotypic and functional changes in bone marrow dendritic cells (BMDCs) stimulated in vitro with the yeast form of S. schenckii or exoantigen (ExoAg) and its ability to trigger a cellular immune response in vitro. Our results demonstrated that the live yeast of S. schenckii and its exoantigen, at a higher dose, were able to activate BMDCs and made them capable of triggering T cell responses in vitro. Whereas the yeast group promoted more pronounced IFN-γ production rather than IL-17, the Exo100 group generated similar production of both cytokines. The exoantigen stimulus suggests a capability to deviate the immune response from an effector Th1 to an inflammatory Th17 response. Interestingly, only the Exo100 group promoted the production of IL-6 and a significant increase of TGF-ß, in addition to IL-23 production. Interestingly, only Exo100 group was capable to promote the production of IL-6 and a significant increase on TGF-ß, in addition with IL-23 detection. Our results demonstrated the plasticity of DCs in translating the data associated with the fungus S. schenckii and ExoAg into differential T cell responses in vitro. The possibility of using ex vivo-generated DCs as vaccinal and therapeutic tools for sporotrichosis is a challenge for the future.

Exposure to Mycobacterium avium decreases the protective effect of the DNA vaccine pVAXhsp65 against Mycobacterium tuberculosis-induced inflammation of the pulmonary parenchyma.

This work investigated the effect of previous Mycobacterium avium exposure on the protective ability of the DNA vaccine pVAXhsp65 against inflammation in the pulmonary parenchyma. BALB/c mice were presensitized with heat-killed M. avium and then immunized with three doses of pVAXhsp65 prior to challenge with Mycobacterium tuberculosis. M. avium sensitization induced high levels of spontaneous IL-5 production that were concomitant with a positive delayed-type hypersensitivity reaction; antigen-specific IFN-γ production was also observed upon splenocyte stimulation. Prior exposure to M. avium resulted in altered cytokine and antibody production induced by immunization with pVAXhsp65; instead of a Th1 response, vaccinated mice previously exposed to M. avium developed a strong Th2 response. This switch to a Th2 response coincided with the loss of the anti-inflammatory effect of pVAXhsp65 vaccination previously observed in the pulmonary parenchyma of mice infected with M. tuberculosis. These results suggest that exposure to environmental mycobacteria can modulate immune responses induced by mycobacterial vaccines other than bacillus Calmette-Guérin.

Immune regulatory effect of pHSP65 DNA therapy in pulmonary tuberculosis: activation of CD8+ cells, interferon-gamma recovery and reduction of lung injury.

A DNA vaccine based on the heat-shock protein 65 Mycobacterium leprae gene (pHSP65) presented a prophylactic and therapeutic effect in an experimental model of tuberculosis. In this paper, we addressed the question of which protective mechanisms are activated in Mycobacterium tuberculosis-infected mice after immune therapy with pHSP65. We evaluated activation of the cellular immune response in the lungs of infected mice 30 days after infection (initiation of immune therapy) and in those of uninfected mice. After 70 days (end of immune therapy), the immune responses of infected untreated mice, infected pHSP65-treated mice and infected pCDNA3-treated mice were also evaluated. Our results show that the most significant effect of pHSP65 was the stimulation of CD8+ lung cell activation, interferon-gamma recovery and reduction of lung injury. There was also partial restoration of the production of tumour necrosis factor-alpha. Treatment with pcDNA3 vector also induced an immune stimulatory effect. However, only infected pHSP65-treated mice were able to produce significant levels of interferon-gamma and to restrict the growth of bacilli.

Synthesis, antimycobacterial activities and cytotoxicity on V79 of 3-[4'-Y-(1,1'-biphenyl)-4-yl]-N,N-dimethyl-3-(4-X-phenyl)-2-propen-1-amine derivatives.

The derivatives of 3-(4'-bromo-[1,1'-biphenyl]-4-yl)-3-(4-X-phenyl)-N,N-dimethyl-2-propen-1-amine (5a-m) were synthesised through a Friedel-Crafts acylation followed by Wittig reaction. The effects of the compounds on standard strains of Mycobacterium sp. (ATCC) and M. tuberculosis isolated from clinical specimens were evaluated. Also the toxicity was determined on V79 cells line using neutral red uptake (NRU), nucleic acid content (NAC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction to measure the cellular viability.

Antimycobacterial activity of 4'-bromo-[1,1'-biphenyl]-4-yl 4-x-phenylmethanone derivatives, and their acute toxicity and cytotoxicity.

The antimycobacterial activity of nine biphenyl methanone (BPM) derivatives against standard strains of Mycobacterium kansasii, M. avium and M. malmoense was determined by colorimetric assay in microplates with the dye Alamar Blue. Acute toxicity of these compounds was also analyzed by determination of CO2 concentration in a respirometric assay using Escherichia coli. The compounds showed weak antimycobacterial activity with a minimal inhibitory concentration (MIC) over 0.038 mmol l-1 and no toxicity was found in E. coli up to 400 mmol l-1. No cytotoxicity was observed on V79 cells up to 0.35 mmol l-1 with 7 of the BPM derivatives, with two exceptions (X = SO2CH3, NO2) that showed some toxicity. The greatest antimycobacterial activity was observed with the SO2CH3 derivative and the application of Principal Component Analysis (PCA) showed a relationship between structure and antimycobacterial activity of the compounds. Two descriptors, nucleophilic superdelocalizability of carbon atom and pi-hydrophobic constant, were necessary to describe this relationship.