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.

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.

Mitogenic response and cytokine production induced by cramoll 1,4 lectin in splenocytes of inoculated mice.

Cramoll 1,4 is a lectin with specific glucose/mannose binding, which is extracted from seeds of Cratylia mollis Mart. Many assays have shown the cytokine expression activity and anti-inflammatory profile of this lectin. The aim of this study was to evaluate the immunostimulatory response, in vitro, of splenocytes in mice previously inoculated, in vivo, with C. mollis (Cramoll 1,4) and Canavalia ensiformis (Con A) lectins. Results demonstrated higher proliferation indexes induced by Cramoll 1,4 than Con A lectin in relation to all experimental groups. Cramoll 1,4 and Con A also induced high levels of IL-2, IL-6, IFN-γ and nitric oxide production. Moreover, Cramoll 1,4 did not induce apoptosis and stimulated a significant number of cells in the S phase of the cell cycle. Results showed that Cramoll 1,4 lectin induces proliferative response and suggested that this lectin can be used as a mitogenic agent in immunostimulatory assays.

Immunological studies and in vitro schistosomicide action of new imidazolidine derivatives

Schistosomiasis is a major public health problem with 207 million people infected and more than 779 million at risk. The drug of choice for treating schistosomiasis is praziquantel (PZQ); however, it is inefficient against immature forms of schistosomes. The aim of this study was to test new imidazolidine derivatives LPSF/PT09 and LPSF/PT10 against adult Schistosoma mansoni worms. IC50, cytotoxicity, immune response and cell viability assays were also available for these imidazolidines. Different concentrations of imidazolidine, from 32 to 320 »M, promoted motor abnormalities in breeding and unpaired worms, and death in 24 hours at higher concentrations. Although LPSF/PT09 and LPSF/PT10 did not affect IFN-³ and IL-10 production, they induced nitric oxide production and showed a similar behavior to praziquantel on cell death test. Thus, these new imidazolidine derivatives should undergo further study to develop schistosomiasis drugs.