Seleção, caracterização e clonagem dos genes fljB e groEL agonistas dos receptores de reconhecimento de padrão do sistema imune inato das aves / Selection, characterization and cloning of the fljB and groEL genes agonists of the innate immune system pattern recognition receptors of birds

The recombinant production of innate immune system pattern recognition receptor agonists has provided a new tool for the production of immunostimulants for animals. The molecular pattern associated with the pathogen (PAMP), flagellin, coded by the fljB gene from Salmonella Typhimirium, and the molecular pattern associated to the damage (DAMP), HSP60, coded by the groEL gene from S. Typhimurium and S. Enteritidis, are recognized by pattern recognition receptors (PRRs) of the innate immune system of birds. In the present study, we performed the cloning of genetic fragments of the genes fljB, from S. Typhimurium, and groEL from S. Typhimurium and S. Enteritidis inserted in expression vector pET100/D-TOPO and transformed in E. coli TO10 cells. The clones were evaluated by colony PCR, plasmidial DNA PCR and genome sequencing in order to confirm the presence of these genes. In the colony PCR, we identified the presence of genes groEL (S. Enteritidis), groEL (S. Typhimurium) and fljB (S. Typhimurium) in 80%, 60% and 80% of the transformed colonies, respectively. The cloning system adopted allowed the production of HSP60 genetic fragment clones and flagellin of Salmonella strains, allowing the posterior use of these clones in gene expression trials, with the future potential of being used as non-specific immunostimulants for birds.

A produção recombinante de agonistas dos receptores do reconhecimento de padrão do sistema imune inato tem fornecido uma nova ferramenta para a produção de imunoestimulantes para animais. O padrão molecular associado ao patógeno (PAMP), flagelina, codificado pelo gene fljB de Salmonella Typhimurium e o padrão molecular associado ao dano (DAMP) HSP60, codificado pelo gene groEL da S. Typhimurium e S. Enteritidis, são reconhecidos por receptores de reconhecimento de padrões (RRPs) do sistema imune inato das aves. No presente estudo, foi feita a clonagem de fragmentos genéticos dos genes fljB de S. Typhimurium e groEL de S. Typhimurium e S. Enteritidis inseridos no vetor de expressão pET100/D-TOPO e transformados em células de E. coli TOP10. Os clones foram avaliados pela PCR de colônia, PCR de DNA plasmidial e sequenciamento genômico para a confirmação da presença desses genes. Na PCR de colônia, foram identificadas em 80%, 60% e 80% das colônias transformadas, a presença dos genes groEL (S. Enteritidis), groEL (S. Typhimurium) e fljB (S. Typhimurium) respectivamente. O sistema de clonagem adotado possibilitou a produção de clones dos fragmentos genéticos da HSP60 e flagelina das cepas de Salmonella, permitindo a utilização posterior desses clones em ensaios de expressão gênica, com potencial futuro de serem utilizados como imunoestimulante inespecífico das aves.

A Novel Recombinant BCG Vaccine Encoding Eimeria tenella Rhomboid and Chicken IL-2 Induces Protective Immunity Against Coccidiosis

A novel recombinant Bacille Calmette-Guerin (rBCG) vaccine co-expressed Eimeria tenella rhomboid and cytokine chicken IL-2 (chIL-2) was constructed, and its efficacy against E. tenella challenge was observed. The rhomboid gene of E. tenella and chIL-2 gene were subcloned into integrative expression vector pMV361, producing vaccines rBCG pMV361-rho and pMV361-rho-IL2. Animal experiment via intranasal and subcutaneous route in chickens was carried out to evaluate the immune efficacy of the vaccines. The results indicated that these rBCG vaccines could obviously alleviate cacal lesions and oocyst output. Intranasal immunization with pMV361-rho and pMV361-rho-IL2 elicited better protective immunity against E. tenella than subcutaneous immunization. Splenocytes from chickens immunized with either rBCG pMV361-rho and pMV361-rho-IL2 had increased CD4+ and CD8+ cell production. Our data indicate recombinant BCG is able to impart partial protection against E. tenella challenge and co-expression of cytokine with antigen was an effective strategy to improve vaccine immunity.

Tuberculosis: looking beyond BCG vaccines.

Tuberculosis (TB) is an infectious disease of international importance and ranks among the top 10 causes of death in the World. About one-third of the world's population is infected with Mycobacterium tuberculosis. Every year, approximately eight million people develop active disease and two million die of TB. The currently used BCG vaccines have shown variable protective efficacies against TB in different parts of the world. Moreover, being a live vaccine, BCG can be pathogenic in immunocompromised recipients. Therefore, there is an urgent need to develop new vaccines against TB. The comparative genome analysis has revealed the existence of several M. tuberculosis-specific regions that are deleted in BCG. The work carried out to determine the immunological reactivity of proteins encoded by genes located in these regions revealed several major antigens of M. tuberculosis, including the 6 kDa early secreted antigen target (ESAT6). Immunization with ESAT6 and its peptide (aa51-70) protects mice challenged with M. tuberculosis. The protective efficacy of immunization further improves when ESAT6 is recombinantly fused with M. tuberculosis antigen 85B. In addition, ESAT6 delivered as a DNA vaccine is also protective in mice. Whether these vaccines would be safe or not cannot be speculated. The answer regarding the safety and efficacy of these vaccines has to await human trials in different parts of the world.