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Articles by Juan Kouri
Total Records ( 3 ) for Juan Kouri
  Viviana Falcon , Ivon Menendez , Nelson Acosta-Rivero , Mineko Shibayama , Marlia-C de la Rosa , Jose Luna- Munoz , Magdalena Miranda-Sanchez , Jorge V. Gavilondo , Deliana Lopez , Santiago Duenas-Carrera , Bienvenido Gra , Glay Chinea , Luisa Tamayo Garcia , Waldo Garcia , Eduardo Vidal , Enrique Arus-Soler , Jose Silva , Felix Alvarez , Emilio F. Acosta , Jesus Seoane , Juan Morales-Grillo , Eduardo Penton , Juan Kouri and Victor Tsutsumi
  Despite of recent advances on acknowledge of hepatitis B virus (HBV) structure and biology, little is known about the morphogenesis and release of virions. In this study, the ultrastructural analysis of HBV components in liver biopsies from chronically HBV-infected patients disclosed complex assembly and morphogenesis pathways for HBV. HBV core (HBcAg) and surface (HBsAg) antigens were specifically identified in all liver biopsies from HVB-infected patients. HBcAg containing core-like particles 24-28 nm in diameter were observed both in nucleus and cytoplasm of hepatocytes. Dane’s-like particles were detected either budding to or into the lumen of ER close to HBsAg containing tubular structures. Besides, Dane’s-like particles were detected in different vesicular compartments resembling multivesicular endosomes. Other kind of enveloped HBV-like particles similar to the previously described cobra-shaped and horn-shaped particles were also observed in hepatocytes. Some of these particles were connected to the vesicle membrane through a stalk 20-22 nm in diameter. On the other hand, spherical subviral particles (SVP) were frequently observed in cytoplasmic vesicles. Moreover, a minor proportion of enveloped HBV-like particles budding through the plasma membrane to the extracellular space and bile canaliculi were detected. Interestingly, Dane’s-like particles in the bile canaliculi and entering into ductular-like cells were shown. Strikingly, Dane’s-like particles close to tubular structures and specific immunolabeling for HBcAg both in cytoplasm and nuclei of stellate-like cells were detected. Remarkably, HVB-like particles appeared entering hepatocytes from large cytoplasmic processes of fibrocytes raising the interesting possibility of a cell to cell passage of HBV through direct transcellular migration.
  Viviana Falcon , Nelson Acosta-Rivero , Nelson Acosta-Rivero , Jose Luna-Munoz , Magdalena Miranda-Sanchez , Maria-C de la Rosa , Ivon Menendez , Bienvenido Gra , Santiago Duenas-Carrera , Waldo Garcia , Eduardo Vilar , Jose Silva , Deliana Lopez , Maritza Gonzalez-Bravo , Celia Fernandez-Ortega , Dionne Casillas , Juan Morales , Juan Kouri and Victor Tsutsumi
  In this study, we examined the expression of hepatitis C virus (HCV) components in hepatocytes and peripheral blood mononuclear cells (PBMC) from patients positive for anti-HCV antibodies and negative for serum HCV-RNA. The samples obtained from 25 randomly selected patients (13 of 25 patients showed no histological evidences of chronic hepatitis and had normal serum ALAT and GGTP levels) were studied by in situ Hybridization and Immunofluorescence assays. The findings show that HCV-RNA of both positive and negative polarity was carried in the hepatocytes of more than 80% of cases. The proportion of cells expressing the negative strand (mean ± SD, 10.25% ± 5.56%) was lower than those expressing positive strand (mean ± SD, 19.88% ± 9.19%) (p=0.0076; Student’s t test). In addition, reaction products suggestive of HCV core, E1 and E2 antigens within hepatocytes were also observed. Both hybridization and immunofluorescence signals were localized in the cytoplasm suggesting that this is the place of active HCV replication. On the other hand, the HCVRNA of positive polarity was detected in PBMC from 16 out of 17 samples analyzed (94%) while the HCV-RNA of negative polarity was detected in 82% of samples investigated. Positive hybridization signals were localized in the cytoplasm of PBMC. Interestingly, 12 out of 13 patients with clinical and histological resolution of hepatitis, contain HCV-RNA in either liver or PBMC. These results provide further evidences that the intermediate replicative form of the HCV genome can persist in hepatocytes and PBMC after apparently complete resolution of chronic hepatitis C.
  Nelson Acosta-Rivero , Joanna Poutou , Alexis Mussachio , Viviana Falcon , Yaraima Aguilera , Armando Rodriguez , Angel Perez , Julio C. Aguilar , Maria C de la Rosa , Felix Alvarez , Juan Morales-Grillo , Juan Kouri and Santiago Duenas-Carrera
  Recently, it has been shown that HCV core proteins (HCcAg) with C-terminal deletions assemble in vitro into virus-like particles (VLPs) in the presence of structured RNA molecules. Results presented in this work showed that a truncated HCcAg variant covering the first 120 aa (HCcAg.120) with a 32 aa N-terminal fusion peptide (6xHistag-XpressTMepitope) interacts with plasmid DNA vaccine. Interestingly, the buoyant density of VLPs containing HCcAg.120 in CsCl gradients changed from 1.15-1,17 g mL1 to 1.30-1.34 g mL1 after addition of plasmid DNA to assembly reactions. In addition, a delay in electrophoretic mobility of HCcAg.120-plasmid samples on agarose gels was observed indicating a direct interaction between VLPs and nucleic acids. Remarkably, addition of either plasmid DNA or tRNA to assembly reactions leaded to heterogeneous and larger VLPs formation than those observed in HCcAg.120 assembly reactions. VLPs containing HCcAg.120 induced a specific IgG antibodies in mice that reacted with hepatocytes from HCV-infected patients. VLPs obtained in this work would be important to elucidate the mechanisms behind the ability of HCcAg to assemble into a nucleocapsid structure. Besides, the capacity of particles containing HCcAg.120 to interact with nucleic acids could be used in the development of DNA vaccines and viral vectors based on these particles.
 
 
 
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