RESUMO
The Schistosoma japonicum fatty acid-binding protein (FABP) is used in the cell membrane to absorb and transport fatty acids, which cannot be resynthesized by the organism and combined with hydrophobic ligands. Among the 5 stages of the worm life cycle examined, FABP messenger ribonucleic acid (mRNA) expression was highest in male adult worms, followed by the liver-stage schistosome, and was the lowest in the lung-stage schistosome. The fabp gene-coding region was cloned and expressed to obtain recombinant S. japonicum FABP (rSjFABP) with a molecular weight of approximately 18 kDa. Mice were then immunized against rSjFABP to prepare anti-FABP serum. Using immunohistochemical techniques, FABP protein was found to localize to the eggshell, parenchyma, and digestive tract. Double-stranded RNA-mediated knockdown of FABP mRNA by RNA interference decreased the number of transcripts by >70%. Moreover, the egg production rate decreased, whereas the abnormal egg ratio was significantly increased in the FABP-silenced group compared with the negative control group (P < 0.05). These results demonstrate that FABP localizes in adults and in various stages. FABP contributes to the egg-laying capacity of adults, which may be related to the reproductive function of S. japonicum.
Assuntos
Proteínas de Ligação a Ácido Graxo/fisiologia , Proteínas de Helminto/fisiologia , Schistosoma japonicum/fisiologia , Animais , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/imunologia , Proteínas de Ligação a Ácido Graxo/isolamento & purificação , Feminino , Regulação da Expressão Gênica , Proteínas de Helminto/genética , Proteínas de Helminto/imunologia , Proteínas de Helminto/isolamento & purificação , Imuno-Histoquímica , Fígado/parasitologia , Pulmão/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/análise , Reação em Cadeia da Polimerase em Tempo Real , Schistosoma japonicum/química , Schistosoma japonicum/genéticaRESUMO
AIMS: The aim of this study was to evaluate the effect of anti-CTLA-4 monoclonal antibody (mAb) on 26-kDa glutathione-S-transferase (GST) vaccine-induced immunity against Schistosoma japonicum infection. METHODS AND RESULTS: Mice immunized with GST before infection with S japonicum cercariae were injected with anti-CTLA-4 mAb. Worm reduction rate of GST was increased from 25.41% in mice with GST immunization to 52.48% in mice with GST plus anti-CTLA-4 mAb. The percentages of regulatory T cells (Tregs) were significantly higher following administration of both GST and anti-CTLA-4 mAb, or anti-CTLA-4 mAb alone. Elevated levels of IFN-γ, IL-2, IL-4 and IL-5 were observed. CONCLUSION: These results demonstrated that CTLA-4 may inhibit the protective effect of GST vaccine, and anti-CTLA-4 mAb may be used as an adjuvant to enhance the immune protection conferred by the GST vaccine by enhancing Th1- and Th2-type immune response.
