Targeting the Immune System with Plant Lectins to Combat Microbial Infections

The arsenal of drugs available to treat infections caused by eukaryotic and prokaryotic microbes has been declining exponentially due to antimicrobial resistance phenomenon, leading to an urgent need to develop new therapeutic strategies. Host-directed immunotherapy has been reported as an attractive option to treat microbial infections. It consists in the improvement of host defenses by increasing the expression of inflammatory mediators and/or controlling of inflammation-induced tissue injury. Although the in vitro antimicrobial and immunomodulatory activities of lectins have been extensively demonstrated, few studies have evaluated their in vivo effects on experimental models of infections. This review aims to highlight the experimental use of immunomodulatory plant lectins to improve the host immune response against microbial infections. Lectins have been used in vivo both prophylactically and therapeutically resulting in the increased survival of mice under microbial challenge. Other studies successfully demonstrated that lectins could be used in combination with parasite antigens in order to induce a more efficient immunization. Therefore, these plant lectins represent new candidates for management of microbial infections. Furthermore, immunotherapeutic studies have improved our knowledge about the mechanisms involved in host–pathogen interactions, and may also help in the discovery of new drug targets

Cytokines and NO in American tegumentary leishmaniasis patients: profiles in active disease, after therapy and in self-healed individuals

Submitted by Kamylla Nascimento ([email protected]) on 2017-12-14T14:26:17Z No. of bitstreams: 1 ART. Cytokines and NO - SOUZA.pdf: 327507 bytes, checksum: 9cb92ad0b2d17463cf0552be0e260631 (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2017-12-15T12:19:28Z (GMT) No. of bitstreams: 1 ART. Cytokines and NO - SOUZA.pdf: 327507 bytes, checksum: 9cb92ad0b2d17463cf0552be0e260631 (MD5)Made available in DSpace on 2017-12-15T12:19:28Z (GMT). No. of bitstreams: 1 ART. Cytokines and NO - SOUZA.pdf: 327507 bytes, checksum: 9cb92ad0b2d17463cf0552be0e260631 (MD5) Previous issue date: 2013Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Universidade de São Paulo (IMT/USP). Instituto de Medicina Tropical de São Paulo. São Paulo, SP, Brazil.Universidade de Pernambuco (HUOC/UPE). Hospital Universitário Oswaldo Cruz. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de imunologia. Recife, PE, Brasil.Studies suggest the influence of immune response on the successful treatment of American tegumentary leishmaniasis (ATL), and indicate the existence of protective immunity in self-healed patients. Thus, the aim of this work was to quantify interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL-) 10, IL-17, IL-22 and nitric oxide (NO) in culture supernatants of PBMC from patients with active disease (AD), after treatment (AT), and from self-healed (SH) and healthy subjects (CT), in response to Leishmania (Viannia) braziliensis insoluble antigen (AgIns). All groups of patients produced IFN-γ, indicating a predominant proinflammatory profile. AD and AT patients presented TNF-α levels, with a slight increase after therapy, whereas it was weakly quantified in SH. Interestingly, NO secretion was significant in these individuals, whereas IL-17 appeared in low levels and seems to be regulated by NO. Although IL-22 was detected in AD, its role is still questionable. The presence of IL-10 in all groups of patients suggests that the cytokine plays distinct roles in the disease. These results indicate that specific cellular immunity takes part against Leishmania, but with some similarities between the different clinical states herein described; these mediators seem to be necessary for the cure to occur

Trypanosoma cruzi cell death induced by the Morita-Baylis-Hillman adduct 3-Hydroxy-2-methylene-3-(4-nitrophenylpropanenitrile)

Submitted by Kamylla Nascimento ([email protected]) on 2017-11-27T11:36:23Z No. of bitstreams: 1 art. Trypanosoma cruzi - sandes.pdf: 5943676 bytes, checksum: c33130d68adc83b9c57c45ec2b59ed34 (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2017-11-27T11:57:20Z (GMT) No. of bitstreams: 1 art. Trypanosoma cruzi - sandes.pdf: 5943676 bytes, checksum: c33130d68adc83b9c57c45ec2b59ed34 (MD5)Made available in DSpace on 2017-11-27T11:57:20Z (GMT). No. of bitstreams: 1 art. Trypanosoma cruzi - sandes.pdf: 5943676 bytes, checksum: c33130d68adc83b9c57c45ec2b59ed34 (MD5) Previous issue date: 2014Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.Universidade Federal de Pernambuco. Departamento de Biofísica e Radiobiologia. Recife, PE, Brazil.Fundação Oswaldo Cruz. Centro Pesquisas Gonçalo Moniz. Laboratório de Biologia Parasitaria. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Imunologia. Recife, PE, Brasil.Universidade Federal da Paraíba. Departamento de Química. João Pessoa, PB, Brasil.Universidade Federal da Paraíba. Departamento de Química. João Pessoa, PB, Brasil.Universidade Federal da Paraíba. Departamento de Química. João Pessoa, PB, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a serious health concern due to the lack of effective vaccines or satisfactory treatment. In the search for new compounds against this neglected disease, we have previously demonstrated that the compound 3-Hydroxy-2-methylene-3-(4-nitrophenylpropanenitrile) (MBHA3), derived from the Morita-Baylis-Hillman reaction, effectively caused a loss of viability in both the epimastigote and trypomastigote forms. However, the mechanisms of parasite death elicited by MBHA3 remain unknown. The aim of this study was to better understand the morphophysiological changes and the mechanism of cell death induced by MBHA3 treatment on T. cruzi. To perform this analysis, we used confocal microscopy and flow cytometry to monitor the fluorescent probes such as annexin-V/propidium iodide (AV/PI), calcein-AM/ethidium homodimer (CA/EH), acridine orange (AO) and rhodamine 123 (Rho 123). Lower concentrations of MBHA3 led to alterations in the mitochondrial membrane potential and AO labeling, but did not decrease the viability of the epimastiogote forms, as determined by the CA/EH and AV/PI assays. Conversely, treatment with higher concentrations of MBHA3 led to extensive plasma membrane damage, loss of mitochondrion membrane potential, DNA fragmentation and acidification of the cytoplasm. Our findings suggest that at higher concentrations, MBHA3 induces T. cruzi epimastigote death by necrosis in a mitochondrion-dependent manner

CD4+CD45RA−FOXP3low Regulatory T Cells as Potential Biomarkers of Disease Activity in Systemic Lupus Erythematosus Brazilian Patients

Heren, we analyzed Treg cells as potential biomarkers of disease activity in systemic lupus erythematosus (SLE) patients. Peripheral blood mononuclear cells from 30 SLE patients (15 active: SLEDAI > 6/15 SLE remission: SLEDAI< 6) and 15 healthy volunteers were purified. Treg immunophenotyping was performed using CD4, CD25, CD45, CD127, and FOXP3 markers. CD4+FOXP3+ Treg activation state was investigated based on CD45RA and FOXP3 expression. To increase the accuracy of our findings, a multivariate linear regression was performed. We showed a significant increase in the frequency of CD4+FOXP3+ Treg cells in SLE patients. However, unlike all other Treg cells phenotypes analyzed, only eTreg (CD4+FOXP3highCD45RA-) (p=0.01) subtype was inversely correlated with disease activity while Foxp3+nontreg (CD4+FOXP3lowCD45RA-) (p=0.003) exerted a direct influence in the outcome of the disease. Foxp3+nontreg cells were the most consistent SLE active indicator, confirmed by multiple linear regression analyses. In summary, our results demonstrate Foxp3+nontreg cells as new biomarkers in the search of an effective therapeutic strategy in SLE

DNA fragmentation induced by MBHA3 on <i>T. cruzi</i> epimastigote forms.

<p>Electrophoresis of total DNA of the control and MBHA3-treated epimastigote forms. Non-specific DNA fragmentation could be observed in cells treated with the 2x IC₅₀ and the 4x IC₅₀ MBHA3. H₂O₂ was used as a positive control of parasite death. M = Low DNA Mass Ladder.</p

Effects of MBHA3 treatment on the acidic compartments of T. cruzi.

<p>(A) Overlay flow cytometric histograms of the control and treated-cells labeled with AO, after 72 hours of drug incubation. A gradual shift of the red fluorescence could be observed in the cells treated with the IC₅₀ and the 2x IC₅₀ of MBHA3. Nevertheless, in cells treated with the 4x IC₅₀ of MBHA3, a striking decrease of the fluorescent signal from red channel was observed. (B–E). Confocal microscopy images of the control (B) and treated-cells (C–E). Control cells presented a normal morphology with a bright green nucleus, pale green cytoplasm and large red-labeled compartments at the posterior end of cells (B). Detail of the IC₅₀-treated culture showing slight changes in the parasite nucleus. (C). Aspect of parasite culture treated with the 2x IC₅₀ of MBHA3 showing severe acidification of the parasite cytoplasm (D). Note the presence of the pyknotic nucleus (white arrow, inset). Parasites treated with the 4x IC₅₀ of MBHA3 showed a round-shape body and a decrease in both green and red AO fluorescent signals (E).</p

Effects of BMHA3 treatment on Anexin V/PI labeling.

<p>Confocal microcopy analysis of control and MBHA3-treated parasites labeled with AV/PI, after 72 hours of incubation. Note the presence of AV and PI double positive cells presenting membrane blebs at the 2x IC₅₀ of MBHA3 (arrow and inset). Drastic morphological changes could be observed by differential interference contrast (DIC, left column) at the 2x and the 4x IC₅₀ of MBHA3.</p

Cytometry analysis of the effects of MBHA3 on Calcein AM/EH.

<p>Flow cytometric dot plots of control (A) and MBHA3-treated cells (B – D) labelled with CA/EH. Cells in the upper left quadrant were positive only for calcein. Cells in the lower right quadrant were positive only for ethidium heterodimer. Events in the upper right quadrant were double positive for both markers, whereas the lower left quadrant corresponds to the cells negative for the both dyes. The dot plots are representative of duplicate experiments with similar results. There were 20,000 recorded events/experimental condition.</p

Chemical structure of MBHA3.

<p>Chemical structure of MBHA3.</p