L-asparaginase isolated from Streptomyces ansochromogenes promotes Th1 profile and activates CD8+ T cells in human PBMC: an in vitro investigation.

AIMS: A new L-asparaginase produced by Streptomyces ansochromogenes UFPEDA 3420 actinobacteria was used in this study against human lymphocyte cultures to evaluate the immunological profile induced by this enzyme. METHODS AND RESULTS: Cultures of lymphocytes were stimulated with S. ansochromogenes L-asparaginase, and cytotoxicity, cell viability, cell stimulation and cytokine production were analysed. This new S. ansochromogenes L-asparaginase induced activation and proliferation of the TCD8+ lymphocyte subset and produced higher TNF-α, IFN-γ, IL-2 and IL-10 levels in a 24-h assay. CONCLUSION: Streptomyces ansochromogenes L-asparaginase is a promising molecule to be used in in vivo models and to deepen preclinical tests against acute lymphoblast leukaemia. SIGNIFICANCE AND IMPACT OF STUDY: 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.

Water-soluble Moringa oleifera lectin interferes with growth, survival and cell permeability of corrosive and pathogenic bacteria.

AIMS: This work evaluated the antibacterial activity of a water-soluble Moringa oleifera seed lectin (WSMoL) by evaluating its effect on growth, survival and cell permeability of Bacillus sp., Bacillus cereus, Bacillus pumillus, Bacillus megaterium, Micrococcus sp., Pseudomonas sp., Pseudomonas fluorescens, Pseudomonas stutzeri and Serratia marcescens. In addition, the effect of lectin on membrane integrity of most sensitive species was also evaluated. All the tested bacteria are able to cause biocorrosion and some are also responsible for human infections. METHODS AND RESULTS: WSMoL inhibited the bacterial growth, induced agglutination and promoted the leakage of proteins from cells of all strains. Bactericidal effect was detected against Bacillus sp., B. pumillus, B. megaterium, Ps. fluorescens and Ser. marcescens. The bacteriostatic effect of lectin was evident with only 6 h of incubation. Fluorescence microscopy of Ser. marcescens showed that WSMoL caused loss of cell integrity and indicated an anti-biofilm activity of the lectin. CONCLUSIONS: WSMoL was active against the bacteria by inhibiting growth and affecting cell permeability. The lectin also interfered with membrane integrity of Ser. marcescens, the most sensitive species. SIGNIFICANCE AND IMPACT OF THE STUDY: The study indicates that WSMoL was active against bacteria that cause serious problems in both industrial and health sectors. Also, the study contributes for the 'state-of-art' on antibacterial mechanisms of lectins.

Rachycentron canadum (cobia) lectin promoted mitogenic response in mice BALB/c splenocytes.

The mitogenic lectins are invaluable tools to study the biochemical changes associated with lymphocyte activation and proliferation of various immune cells. Rachycentron canadum lectin (RcaL) was detected and purified from serum of cobia fish. The aim of this study was to evaluate the proliferative response and cytokine production in splenocytes of mice in vitro stimulated with RcaL lectin; Canavalia ensiformis lectin (Con A) was used as positive control. A high proliferation index was induced by RcaL in relation to control cells. Furthermore, RcaL induced higher IL-2 and IL-6 production in relation to control. The cell viability was 90% in splenocytes treated with RcaL lectin, but RcaL promoted significant late apoptosis after 24 and 48 h in relation to control. RcaL induced proliferative responses suggesting that this lectin can be used as a mitogenic agent in immunostimulatory assays.