Schistosoma mansoni antigens alter the cytokine response in vitro during cutaneous leishmaniasis

Schistosoma mansoni infection or associated products are able to down-modulate the type 1 CD4+ T cell inflammatory response characteristic of autoimmune diseases. In this study, we evaluated how S. mansoni antigens altered the immune response that was induced by the soluble Leishmania antigen (SLA) from cutaneous leishmaniasis (CL) patients. Cytokines were measured from the supernatants of peripheral blood mononuclear cell cultures stimulated with SLA. This was performed using the sandwich enzyme linked immunosorbent assay technique in the presence or absence of S. mansoni recombinant antigens Sm29, SmTSP-2 and PIII. The addition of S. mansoni antigens to the cultures resulted in the reduction of interferon gamma (IFN-γ) levels in 37-50 percent of patients. Although to a lesser extent, the antigens were also able to decrease the production of tumour necrosis factor-alpha (TNF-α). We compared patients that either had or did not have reduction in IFN-γ and TNF-α production in cultures stimulated with SLA in the presence of S. mansoni antigens. We found that there was no significant difference in the levels of interleukin (IL)-10 and IL-5 in response to S. mansoni antigens between the groups. The antigens used in this study down-modulated the in vitro proinflammatory response induced by SLA in a group of CL patients through a currently undefined mechanism.

Molecular characterization and T and B cell epitopes prediction of Mycoplasma synoviae 53 strain VlhA hemagglutinin

Mycoplasma sinoviae is a major pathogen of poultry causing synovitis and respiratory infection. M. synoviae hemagglutinin (VlhA) is a lipoprotein encoded by related multigene families that appear to have arisen by horizontal gene transfer. It is an abundant immunodominant surface protein involved in host-parasite interaction mediating binding to host erythrocytes. Herein, we have performed in silico analysis of the vlhA gene product from the Mycoplasma synoviae 53 strain and compared it to the VlhA protein of M. synoviae WUV1853 strain. The VlhA of the M. synoviae 53 strain possesses 569 amino acids and showed 85 percent identity with the VlhA protein of the M. synoviae WUV1853 strain. Further, a signal peptide was identified from amino acid M1 to D28 and a cleavage site between D28 and Q29, both located in the N-terminal domain of the molecule. Additionally, an insertion of PAPT amino acids was observed between T30-P35 and a deletion of the amino acids GTPGNP within the PRR region of the VlhA from the M. synoviae 53 strain, which may be related to its reduced virulence. Finally, we have identified 17 B cell epitopes and 22 T cells epitopes within the VlhA from the M. synoviae 53 strain. The B cell epitope S263-D277 and the T cell epitopes N45-N54 and G58-N67 showed 100 percent and 87-100 percent identity, respectively, with regions of VlhA protein of tested Mycoplasma synoviae and Mycoplasma galisepticum strains. Thus, these peptides represent new candidate molecules for the development of efficient diagnostic assays and new subunit vaccines.

Clustering and artificial neural networks: Classification of variable lengths of Helminth antigens in set of domains

A new scheme for representing proteins of different lengths in number of amino acids that can be presented to a fixed number of inputs Artificial Neural Networks (ANNs) speel-out classification is described. K-Means's clustering of the new vectors with subsequent classification was then possible with the dimension reduction technique Principal Component Analysis applied previously. The new representation scheme was applied to a set of 112 antigens sequences from several parasitic helminths, selected in the National Center fo Biotechnology Information and classified into fourth different groups. This bioinformatic tool permitted the establishment of a good correlation with domains that are already well characterized, regardless of the differences between the sequences that were confirmed by the PFAM database. Additionally, sequences were grouped according to their similarity, confirmed by hierarchical clustering using ClustalW.

Salmonella como vetor de vacinas vivas orais / Live oral vaccines using salmonella

Hß alguns anos, foram desenvolvidas as primeiras linhagens atenuadas de Salmonella para serem utilizadas como candidatas a vacinas vivas orais contra a febre tifóide. No início, ainda eram desconhecidas as mutações responsáveis pelo fenótipo atenuado, mas, com o acúmulo de conhecimento sobre a genética associada à virulência, surgiram novas linhagens com atenuações geneticamente definidas. Muitas linhagens de S. enterica sorotipo Typhimurium e S. enterica sorotipo Typhi já foram bem estudadas quanto à capacidade de induzir resposta imunológica em modelos animais e em humanos. Com o desenvolvimento de sistemas de clonagem e expressão eficientes, o uso destas linhagens vacinais extrapolou o problema das salmoneloses, uma vez que tornou-se possível a produção e administração de antígenos de diferentes agentes patogênicos. Recentemente, uma nova tecnologia que vem sendo explorada é o uso de Salmonella como carreadora de vacinas de DNA. Tais vacinas já se mostraram capazes de induzir potentes respostas humorais e celulares contra antígenos heterólogos nos organismos hospedeiros. Todo este progresso nos estudos com as linhagens vacinais de Salmonella demonstra o potencial que elas possuem para a produção das futuras vacinas contra doenças infecciosas, parasitárias e até mesmo contra o câncer.

Induction of protective immunity against Schistosoma mansoni infection by antigens purified from PIII, a fraction of adult worm, associated to the downregulation of granuloma formation

This study was performed in order to define Schistosoma mansoni antigens able to function as modulator agents in BALB/c mice granulomatous hypersensitivity to parasite egg. The antigens P-24, P-35 and P-97 were purified by affinity chromatography from a fraction of S. mansoni adult worm antigenic preparation, denominated PIII, involved in the inhibition of granulomatous response to eggs. Immunization of mice with these antigens, in the presence of Corynebacterium parvum and Al(OH)3 as adjuvant, induced a significant protection degree against challenge infection, as observed by the decrease on worm burden recovered from portal system. In vitro blastogenesis assays revealed that purified antigens were able to induce significant proliferation of spleen cells from S. mansoni-infected mice. This protection was correlated to significant decrease in granuloma size induced by PIII. From these results, we concluded that PIII preparation contains antigens capable of mediating protective anti-parasite immunity and down-regulating granulomatous hypersensitivity to S. mansoni eggs.

Determinaçäo das condiçöes ótimas para detecçäo de anticorpos contra coynebacterium pseudotuberculosis através de método imunoenzimático (ELISA) / Enzyme linked immunosorbent assay (ELISA): optimal conditions for detection of antibodies produced against corinebacterium pseudotuberculosis

Resumo: O ensaio imunoenzimático (ELISA) foi utilizado para mensurar os níveis de anticorpos contra a exotoxina, linfadenina e os antigenos solúveis extraídos por SDS e por ultr-som do Corynebacterium pseudotuberculosis, nos soros de caprinos normais e naturalmente infectados. Nossos resultados indicam a exotoxina e a linfadenina como os melhores antigenos, dentre os estudados, para detectar anticorpos específicos contra o Corynebacterium pseudotuberculosis (au)