Proliferative Effect of Tilapia Fish (Oreochromis niloticus) Lectin on BALB/c Mice Splenocytes.

BACKGROUND: Lectins have been studied in recent years due to their immunomodulatory activities. OBJECTIVE: We purified a lectin named OniL from tilapia fish (Oreochromis niloticus) and here we analyzed the cell proliferation and cytokine production in Balb/c mice splenocytes. METHODS: Cells were stimulated in vitro in 24, 48, 72 hours and 6 days with different concentrations of OniL and Con A. Evaluation of cell proliferation was performed through [3H]-thymidine incorporation, cytokines were investigated using ELISA assay and cell viability assay was performed by investigation of damage through signals of apoptosis and necrosis. RESULTS: OniL did not promote significant cell death, induced high mitogenic activity in relation to control and Con A and stimulated the cells to release high IL-2 and IL-6 cytokines. CONCLUSION: These findings suggest that, like Con A, OniL lectin can be used as a mitogenic agent in immunostimulatory assays.

CasuL: A new lectin isolated from Calliandra surinamensis leaf pinnulae with cytotoxicity to cancer cells, antimicrobial activity and antibiofilm effect.

This work describes the isolation of a lectin (CasuL) from the leaf pinnulae of Calliandra surinamensis and the evaluation of its cytotoxic, antimicrobial and antibiofilm properties. Proteins from pinnulae extract were precipitated with ammonium sulphate (60% saturation) and submitted to Sephadex G-75 chromatography, which yielded isolated CasuL (purification factor: 113). Native CasuL is an acidic protein (pI 5.82) with a relative molecular mass of 48kDa. This lectin is also an oligomeric protein composed of three subunits and mass spectrometry revealed similarities with a Sorghum bicolor protein. CasuL did not undergo unfolding when heated but changes in conformation and hemagglutinating activity were detected at basic pH. CasuL did not reduce the viability of human peripheral blood mononuclear cells but was toxic to leukemic K562 cells (IC50 67.04±5.78µg/mL) and breast cancer T47D cells (IC50: 58.75±2.5µg/mL). CasuL (6.25-800µg/mL) only showed bacteriostatic effect but was able to reduce biofilm formation by Staphylococcus saprophyticcus and Staphylococcus aureus (non-resistant and oxacillin-resistant isolates). CasuL showed antifungal activity against Candida krusei causing alterations in cell morphology and damage to cell wall. In conclusion, the pinnulae of C. surinamensis leaves contain a thermo-stable lectin with biotechnological potential as cytotoxic, antibiofilm, and antifungal agent.