ABSTRACT
Toxoplasmosis, caused by Toxoplasma gondii, is a major public concern owing to its neurotropic nature and high morbidity and mortality rates in immunocompromised patients and newborns. Current treatment for this disease is inefficient and produces side effects. Inflammatory mediators produced during T. gondii infection (e.g., cytokines and nitric oxide) are crucial in controlling parasite replication. In this context, Tityus serrulatus venom (TsV) induces the production of inflammatory mediators by immune cells. Thus, this study aimed to isolate and identify the components of TsV with potential anti-T. gondii activity. TsV was extracted from scorpions and lyophilized or loaded onto a column to obtain its fractions. TsV subfractions were obtained using chromatography, and its amino acid sequence was identified and applied to peptide design using bioinformatics tools. The C57BL/6 mice and their harvested macrophages were used to test the anti-Toxoplasma activity of TsV components and peptides. TsV and its fraction F6 attenuated the replication of tachyzoites in macrophages and induced nitric oxide and cytokine (IL-12, TNF, and IL-6) production by infected cells, without host cell toxicity. Moreover, Su6-B toxin, a subfraction of F6, demonstrated anti-T. gondii activity. The partially elucidated and characterized amino acid sequence of Sub6-B demonstrated 93% similarity with T. serrulatus 2 toxin (Ts2). Ts2 mimetic peptides ("Pep1," "Pep2a," and "Pep2b") were designed and synthesized. Pep1 and Pep2a, but not Pep2b, reduced the replication of tachyzoites in macrophages. In vivo, treatment of T. gondii-infected mice with Pep1, Pep2a, or Pep2b decreased the number of cerebral cysts and did not induce hepatotoxicity in the animals. Taken together, our data show promising immunomodulatory and antiparasitic activity of TsV that could be explored and applied in future therapies for treating infectious parasitic diseases such as toxoplasmosis.
Subject(s)
Scorpion Venoms , Toxoplasmosis , Animals , Chemistry Techniques, Synthetic , Cytokines , Humans , Mice , Mice, Inbred C57BL , Scorpion Venoms/therapeutic use , Scorpions , Toxoplasma , Toxoplasmosis/drug therapyABSTRACT
O fracionamento da secreção das glândulas acetabulares de cercárias do Schistosoma mansoni em coluna de Sephadex G-SO seguida por uma coluna de Sepharose-l 2 no sistema FPLC, isolou componentes da secreção com atividade antigênica e enzimática. Uma protease de 47 kDa migra como banda única em geis de SDS-PAGE. Um anticorpo monoclonal foi produzido e reconhece somente a protease de 47 kDa. Uma coluna de imunoafinidade com anticorpos monoclonais foi usada para purificar esta protease. A protease apresenta atividade sobre algumas macromoléculas tais como elastina, colágeno, gelatina e caseina. Isto sugere que a enzima pode ser parte de um complexo de enzimas que a cercária usa para penetrar na pele do hospedeiro. A enzima é de natureza glicoproteíca, apresenta pH ótimo em torno de 10 quando se utiliza tampão tris-HCL. Experimentos com inibidores sugere que a enzima purificada é uma serino protease. Experimentos de proteção utilizando como antígenos componentes da secreção de cercárias purificadas ou sem i fracionadas mostraram ser capazes de conferir uma proteção significativa em camundongos frente a infecção com cercárias.
