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AELCe showed a moderate bacteriostatic activity and promoted an immunomodulatory status through higher production of Th1 cytokines, nitric oxide release and T CD8 lymphocytes stimulation.

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In this study, we report the purification and characterization of a multifunctional lectin (MvFL) from Microgramma vacciniifolia fronds as well as its immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). MvFL (pI 4.51; 54kDa) is a glycoprotein able to inhibit trypsin activity and that has sequence similarities (32% coverage) with a plant RNA-binding protein. Hemagglutinating activity of MvFL was not altered by heating at 100°C for 30min, but was reduced in alkaline pH (8.0 and 9.0). Fluorimetric analyses showed that this lectin did not undergo marked conformational changes when heated. However, the MvFL conformation changed depending on the pH. MvFL at 6.25-25μg/mL was not cytotoxic to lymphocytes present among PBMCs. The PBMCs incubated for 24h with the lectin (12.5μg/mL) showed increased TNF-α, IFN-γ, IL-6, IL-10, and nitric oxide production. MvFL also stimulated T lymphocytes from PBMCs to differentiate into CD8 cells. The activation (indicated by CD28 expression) of these cells was also stimulated. In conclusion, MvFL is a heat-stable and multifunctional protein, with both lectin and trypsin inhibitor activities, and capable of inducing predominantly a Th1 response in human PBMCs as well as activation and differentiation of T lymphocytes.

Benznidazole (Bz) is the recommended drug for the treatment of Chagas disease; however, its efficacy may vary according to the sensitivity of Trypanosoma cruzi strains to the drug and host immune background. The study evaluated the immune response of peripheral blood mononuclear cells (PBMC) that were infected in vitro with the Colombian strain (Col) and treated with Bz. The co‐cultures were incubated for 24 h, 5 and 10 days, where cytokine dosage was performed in the supernatant and evaluation of the cells for CD28+ and CTLA‐4+ molecules in CD4+ and CD8+ lymphocytes, and CD80+, CD86+ and HLA‐DR+ in CD14+ cells. The results showed that Col induced a strong inflammatory response, with an increase in IFN‐γ and TNF early in the infection (24 h), however, from 5 days of infection on, TNF production declined, and IL‐10 production increased, which may be associated with a control mechanism of the exacerbated inflammatory response. The Bz treatment did not significantly alter the frequencies of the phenotypes evaluated both T cell subsets and CD14+ cells. Therefore, this study reinforces the need for typing the patient's strain to guide therapy and promote individualized treatment protocols due to the heterogeneous genetic background among T. cruzi strains.

L-asparaginase is an indispensable component of the chemotherapeutic treatment of acute lymphoblast leukaemia (ALL) and acute myeloid leukaemia (AML). Currently, drugs such as Asparaginase , Kidrolase , and Elspar and Erwinase are efficient against leukemic disease, but promote immunosuppression and other side effects in human organisms. Our purified S. ansochromogenes L-asparaginase showed promissory results inducing, in vitro, higher immunostimulation in human PBMC, especially in T CD8 lymphocyte subsets.

Trypanosoma cruzi causes the lethal Chagas disease, which is endemic in Latin America. Flowers of Moringa oleifera (Moringaceae) express a trypsin inhibitor (MoFTI) whose toxicity to T. cruzi trypomastigotes was previously reported. Here, we studied the effects of MoFTI on the viability of human peripheral blood mononuclear cells (PBMCs) as well as on the production of cytokines and nitric oxide (NO) by T. cruzi-infected PBMCs. Incubation with MoFTI (trypsin inhibitory activity: 62 U/mg) led to lysis of trypomastigotes (LC50 of 43.5 µg/mL) but did not affect the viability of PBMCs when tested at concentrations up to 500 µg/mL. A selectivity index > 11.48 was determined. When T. cruzi-infected PBMCs were treated with MoFTI (43.5 or 87.0 µg/mL), the release of the pro-inflammatory cytokine TNF-α and INF-γ, as well as of NO, was stimulated. The release of the anti-inflammatory cytokine IL-10 also increased. In conclusion, the toxicity to T. cruzi and the production of IL-10 by infected PBMCs treated with MoFTI suggest that this molecule may be able to control parasitemia while regulating the inflammation, preventing the progress of Chagas disease. The data reported here stimulate future investigations concerning the in vivo effects of MoFTI on immune response in Chagas disease.