Whole Yeast Vaccine Displaying ZIKV B and T Cell Epitopes Induces Cellular Immune Responses in the Murine Model.

Improving antigen presentation is crucial for the success of immunization strategies. Yeasts are classically used as biofactories to produce recombinant proteins and are efficient vehicles for antigen delivery, in addition to their adjuvant properties. Despite the absence of epidemic outbreaks, several vaccine approaches continue to be developed for Zika virus infection. The development of these prophylactic strategies is fundamental given the severity of clinical manifestations, mainly due to viral neurotropism. The present study aimed to evaluate in vivo the immune response induced by P. pastoris recombinant strains displaying epitopes of the envelope (ENV) and NS1 ZIKV proteins. Intramuscular immunization with heat-attenuated yeast enhanced the secretion of IL-6, TNF-α, and IFN-γ, in addition to the activation of CD4+ and CD8+ T cells, in BALB/c mice. P. pastoris displaying ENV epitopes induced a more robust immune response, increasing immunoglobulin production, especially IgG isotypes. Both proposed vaccines showed the potential to induce immune responses without adverse effects, confirming the safety of administering P. pastoris as a vaccine vehicle. Here, we demonstrated, for the first time, the evaluation of a vaccine against ZIKV based on a multiepitope construct using yeast as a delivery system and reinforcing the applicability of P. pastoris as a whole-cell vaccine.

Pectin-like polysaccharide extracted from leaves Crataeva tapia promotes antioxidant, immunomodulatory and emulsifiers applied in therapeutic formulations.

The objective of this work was to isolate a polysaccharide similar to pectin from Crataeva tapia leaves, not yet reported in the literature, and to evaluate its antioxidant, cytotoxic and immunomodulatory profile. Pectin was extracted from the leaves in three stages, organic solvent followed by acidified water and ethanol precipitation. With the pectin obtained, the physicochemical characterization of the molecule was carried out using high-performance liquid chromatography, Fourier-transform infrared spectroscopy, nuclear magnetic resonance (13C and 1H) and different thermal and elemental analysis. Furthermore, the antioxidant activities were evaluated in vitro, and using human peripheral blood mononuclear cell culture, cytotoxicity and immunostimulatory actions were investigated. Physical and chemical analyses showed characteristic signs of pectin. Antioxidant activity tests showed that pectin had moderate to low antioxidant activity. Furthermore, pectin did not affect the viability of erythrocytes and PBMC and induced an immunostimulatory state when it promoted the production of cytokines IL-6, IL-10 and TNF-α and increased the activation of CD8 + T lymphocytes. This study showed that pectin from Crataeva tapia is not cytotoxic and promoted a pro-inflammatory profile in peripheral blood mononuclear cell with application as an immunostimulating and emulsifying compound.

Characterization of a lignin from Crataeva tapia leaves and potential applications in medicinal and cosmetic formulations.

Lignins are phenolic macromolecules that have several applications. In this work, we examine some biological activities of a lignin-like macromolecule isolated from the Crataeva tapia leaves, not yet studied to evaluate its potential applications in medicinal and cosmetic formulations. Lignin was obtained by alkaline delignification and its physical-chemical characterization was made by means of FT-IR, UV-Vis, NMR spectroscopy, elementary analysis, molecular mass determination and thermal analysis. Lignin is of the GSH type, with levels of hydrogen (5.10%), oxygen (27.18%), carbon (67.60%), nitrogen (0.12%) and phenolic content of 189.6 ± 9.6 mg GAE/g. In addition, it is a thermally stable macromolecule with low antioxidant activity. Cytotoxicity and cytokine production were assessed by flow cytometry. The photoprotective activity was evaluated by adding different concentrations of lignin to a commercial cream. Lignin was not cytotoxic, it stimulated the production of TNF-α, IL-6 and IL-10 and did not promote a significant change in nitric oxide levels. In addition, this macromolecule was able to promote increased absorption of ultraviolet light from a commercial cream. These results reinforce the ethnopharmacological use of C. tapia leaves and suggest the need for further studies to determine the potential medicinal and cosmetic applications (sunscreen) of lignin from C. tapia leaves.

Evaluation of cytotoxic, immunomodulatory effects, antimicrobial activities and phytochemical constituents from various extracts of Passiflora edulis F. flavicarpa (Passifloraceae).

The leaves of P. edulis were subjected to physicochemical analysis, such as ion content, extractives, and structural molecules. The hexanic, ethanolic and ethyl acetate extracts were submitted to phytochemical analyzes by GC-MS, HPLC-MS, and spectrophotometry. In addition, antioxidant (DPPH, ABTS and TAA methods) potential, antimicrobial (MIC method) action, cytotoxicity and immunostimulant activity (flow cytometry analysis) were performed. The extracts showed a moderate antioxidant capacity and revealed the presence of several metabolites, mainly phenols, such as caffeic acid, p-coumaric acid and luteolin. The ethyl acetate and ethanolic extracts showed antifungal activity. In addition, the extracts did not affect splenocytes viability at 12.5 µg/mL and promoted the production of IL-6, IL-10, IL-17 and TNF-α cytokines. P. edulis extracts showed antifungal and antioxidant activity and were able to induce immunostimulatory action in splenocyte cultures in vitro.

Lignin isolated from Caesalpinia pulcherrima leaves has antioxidant, antifungal and immunostimulatory activities.

Caesalpinia pulcherrima is a shrub with worldwide distribution used as an ornamental plant. In this study, we extracted a lignin from the C. pulcherrima leaves and investigated its biological functions. The lignin was characterized by FT-IR, UV-Vis, GPC, TGA and nuclear magnetic resonance (1H and 13C). The antioxidant activity was evaluated using phosphomolybdenum complexation methods (TAA), sequestration of DPPH and ABTS radicals, reducing power, formation of nitrite radical and iron chelating activity (Fe2 +). Antifungal activity was made using Candida spp., Aspergillus spp. and Cryptococcus neoformans strains. Cytotoxicity, oxidative stress, and cytokine production were performed using mouse splenocytes. The lignin showed maximal UV-Vis at ~280 nm, 22.27 L/g·cm of absorptivity and, 2,503 kDa of molecular weight. Phenolic compounds (41.33 ± 0.65 mg GAE/g) and indications of a guaiacyl-syringyl-hydroxyphenyl (GSH)-type composition were found. Antioxidant activities of lignin to TAA (40±1.2%) and to DPPH (16.9±0.2%) was high and showed antifungal potential, especially against Candida spp. (IC50 = 31.3 µg/mL) and C. neoformans (15.6 µg/mL). In mouse splenocytes, the lignin was not cytotoxic and stimulated the cell proliferation and cytokine release. These results indicate that C. pulcherrima lignin has the potential to be used as antifungal and immunostimulant compound.