The leishmaniases are multifactorial zoonotic diseases requiring a multidisciplinary One Health approach for diagnosis and control. For leishmaniasis diagnosis, here we describe production of a new recombinant protein based on a kinesin-related gene of Leishmania braziliensis (Lbk39), which shows 59% amino acid identity to the L. infantum homologue. The Lbk39 gene was synthesized, inserted into the pLEXSY-sat2 vector and transfected into L. tarentolae cells by electroporation. Culturing was carried out, and the secreted recombinant protein with a C-terminal histidine tag purified using nickel affinity chromatography on the culture supernatant, yielding a final product at 0.4 mg/mL. An indirect enzyme linked immunosorbent assay (ELISA) was standardised using sera from 74 Brazilian patients with cutaneous leishmaniasis and 11 with visceral leishmaniasis. Optimal ELISA conditions were established for the Lbk39 antigen in comparison with a crude extract from L. braziliensis. The sensitivity, specificity analysis and receiver operating characteristic (ROC) curve were determined with a significance level of 5%. The ROC curve showed a good accuracy with an area under curve (AUC) = 0.967, p < 0.001 (0.941–0.993) for CL patients and an AUC = 100 (100-100) for VL patients. The values of sensitivity and specificity were 88 and 98% for CL and 100 and 100% for VL, respectively. The study showed good production and expression of the target protein and has generated a potential new antigen for the diagnosis of leishmaniasis.

Antigen formulation is the main feature for the success of leishmaniosis diagnosis and vaccination, since the disease is caused by different parasite species that display particularities which determine their pathogenicity and virulence. It is desirable that the antigens are recognized by different antibodies and are immunogenic for almost all Leishmania species. To overcome this problem, we selected six potentially immunogenic peptides derived from Leishmania histones and parasite membrane molecules obtained by phage display or spot synthesis and entrapped in liposome structures. We used these peptides to immunize New Zealand rabbits and determine the immunogenic capacity of the chimeric antigen. The peptides induced the production of antibodies as a humoral immune response against L. braziliensis or L. infantum. Next, to evaluate the innate response to induce cellular activation, macrophages from the peptide mix-immunized rabbits were infected in vitro with L. braziliensis or L. infantum. The peptide mix generated the IFN-γ, IL-12, IL-4 and TGF-β that led to Th1 and Th2 cellular immune responses. Interestingly, this mix of peptides also induced high expression of iNOS. These results suggest that the mix of peptides derived from histone and parasites membrane molecules was able to mimic parasites proteins and induce cytokines important to CD4+ T cell Th1 and Th2 differentiation and effector molecule to control the parasite infection. Finally, this peptide induced an immune balance that is important to prevent immunopathological disorders, inflammatory reactions, and control the parasite infection.

No Brasil, a atual exploração comercial de plantas medicinais, tanto para consumo interno como para exportação é ainda muito limitada, visto que produção e produtividade dependem de incentivos e estudos que possibilitem agregar valor a estes produtos agrícolas. Portanto, a necessidade de investigações fitoquímicas, além de desenvolvimento de novas tecnologias na área de fitoterápicos que contribuam para a melhoria e controle de qualidade das plantas torna-se evidente. Nesta perspectiva, realizou-se um screening fitoquímico do Nasturtium officinale R. Br.; planta pertencente à família Brassicaceae, popularmente conhecida por agrião. Para comparação dos resultados obtidos, realizou-se uma avaliação por cromatografia em camada delgada (CCD). A presença de compostos fenólicos simples e heterosídicos (fenilpropanóides e flavonóides), saponinas (esteróidais e terpênicas policíclicas) e compostos contendo enxofre (glucosinolatos) detectadas no screening fitoquímico foi confirmada por CCD. A identificação dos mesmos se deu por meio de comparação com amostras autênticas e dados de literatura, permitindo desta forma, qualificar o Nasturtium officinale R. Br com as propriedades referenciadas na literatura para a sua eficácia e aplicabilidade fitoterápica.