Vaccine-induced early control of hepatitis C virus infection in chimpanzees fails to impact on hepatic PD-1 and chronicity

Broad T cell and B cell responses to multiple HCV antigens are observed early in individuals who control or clear HCV infection. The prevailing hypothesis has been that similar immune responses induced by prophylactic immunization would reduce acute virus replication and protect exposed individuals from chronic infection. Here, we demonstrate that immunization of na?ve chimpanzees with a multicomponent HCV vaccine induced robust HCV-specific immune responses, and that all vaccinees exposed to heterologous chimpanzee-adapted HCV 1b J4 significantly reduced viral RNA in serum by 84%, and in liver by 99% as compared to controls (P=0.024 and 0.028, respectively). However, despite control of HCV in plasma and liver in the acute period, in the chronic phase, 3 of 4 vaccinated animals developed persistent infection. Analysis of expression levels of proinflammatory cytokines in serial hepatic biopsies failed to reveal an association with vaccine outcome. However, expression of IDO, CTLA-4 [corrected] and PD-1 levels in liver correlated with clearance or chronicity. CONCLUSION: Despite early control of virus load, a virus-associated tolerogenic-like state can develop in certain individuals independent of vaccination history.     

Short-term memory formation and long-term memory consolidation are enhanced by cellular prion association to stress-inducible protein 1

Cellular prion protein (PrP(C)) is a cell surface glycoprotein that interacts with several ligands such as laminin, NCAM (Neural-Cell Adhesion Molecule) and the stress-inducible protein 1 (STI1). PrP(C) association with these proteins in neurons mediates adhesion, differentiation and protection against programmed cell death. Herein, we used an aversively motivated learning paradigm in rats to investigate whether STI1 interaction with PrP(C) affects short-term memory (STM) formation and long-term memory (LTM) consolidation. Blockage of PrP(C)-STI1 interaction with intra-hippocampal infusion of antibodies against PrP(C) or STI1 immediately after training impaired both STM and LTM. Furthermore, infusion of PrP(C) peptide 106-126, which competes for PrP(C)-STI1 interaction, also inhibited both forms of memory. Remarkably, STI1 peptide 230-245, which includes the PrP(C) binding site, had a potent enhancing effect on memory performance, which could be blocked by co-treatment with the competitive PrP(C) peptide 106-126. Taken together, these results demonstrate that PrP(C)-STI1 interaction modulates both STM and LTM and suggests a potential use of ST11 peptide 230-245 as a pharmacological agent.     

Comparative immunogenicity analysis of modified vaccinia Ankara vectors expressing native or modified forms of hepatitis C virus E1 and E2 glycoproteins

We have evaluated in C57/Bl6 and HLA-A2.1 transgenic mice the immunogenicity of three MVA vectors expressing either native HCV E1E2 polyprotein, truncated and secreted E1 (E'1(311)) and E2 (E'2(661)) proteins, or a chimeric E1E2 heterodimer presented at the plasma membrane. Immunization induced mainly a Th1 response in HLA-A2.1 transgenic mice while a Th2-type response was detected in C57/Bl6 mice. Comparison of the three vectors shows an increase in the humoral response when antigens are secreted or membrane bound, and slightly in the cellular response when antigens are exposed on the cell surface.     

Pregnancy in patients with chronic renal insufficiency at Hospital de Clínicas of Porto Alegre, Brazil

Chronic renal insufficiency (CRI) decreases reproductive capability. The biggest challenge in monitoring pregnant women with renal disease is to keep the intrauterine environment favorable to the fetus. One of the common prognosis in this kind of pregnancy involves premature birth, restricted growth and mental retardation. Also, the risk of developing complications is higher for the mother. This study focuses on evaluating CRI patients' clinical conditions during pregnancy, checking fetal development and birth and verifying the prevalence of CRI in pregnant women attended at Hospital de Clínicas of Porto Alegre-Brazil (HCPA). This is a retrospective study with both a control and an case group of pregnant women with CRI who delivered their babies at HCPA from 1989 to 1999. The case group is composed of pregnant women with CRI, while the control group was paired according to maternal and gestational ages and to the time of the delivery, which should be the same both in the experimental and in the control group. Among the criteria usually used to identify CRI, we chose the creatinine level higher than 1.5 mg/dL. Significance was established in 0.05%. Our results demonstrate that the prevalence of CRI was 6/10,000 births. Average maternal age was 28. Sixty five per cent of the patients, in both the groups, underwent prenatal monitoring, 40% presented preeclampsia, 48% presented urinary infection. Among the CRI complications, 48% of the cases presented anemia and 56% presented systemic hypertension. Average hematocrit was 24% while hemoglobin was 6.7 g/dL, which leads us to the conclusion that patients presented anemia during pregnancy. Average creatinine was 4.61 mg/dL. It is relevant that 64% of the CRI cases migrated to a substitutive renal therapy method. As for the fetus evolution in the case group, we confirmed the findings of previous studies, such as larger number of premature births (newborns younger than 36 weeks in 60% of the cases), larger number of cesarean section (56%), lower weight at birth (1980 gr. in average), lower APGAR scores in the first and fifth minute (4.13 and 5.08, respectively) in comparison to the control group (7.52 and 8.63, respectively). We can state that babies born from CRI patients present underdevelopment. Also, mothers with CRI develop more complications during pregnancy.     

Vaccination with an adenoviral vector encoding hepatitis C virus (HCV) NS3 protein protects against infection with HCV-recombinant vaccinia virus

Cellular immune response plays an important role in the clearance of hepatitis C virus (HCV). Thus, development of efficient ways to induce anti-viral cellular immune responses is an important step toward prevention and/or treatment of HCV infection. With this aim, we have constructed a replication-deficient recombinant adenovirus expressing HCV NS3 protein (RAdNS3). The efficacy of RAdNS3 was tested in vivo by measuring the protection against infection with a recombinant vaccinia virus expressing HCV-polyprotein (vHCV1-3011). Immunisation with 10(9)pfu of RAdNS3 induced anti-NS3 humoral, T helper and T cytotoxic responses. We identified eight epitopes recognised by IFN-gamma producing cells, five of them exhibiting lytic activity. Moreover, we show that RAdNS3 immunised mice were protected against challenge with vHCV1-3011 and that this protection was mediated by CD8(+) cells. In conclusion, our results suggest that adenoviral vectors encoding NS3 might be useful for the induction of prophylactic and/or therapeutic anti-HCV immunity.     

Immune response and protection in mice inoculated with Leishmania amazonensis clones expressing different degrees of virulence

The induction of protective immunity to Leishmania amazonensis was investigated by injection of parasite clones of low and medium virulence into susceptible mice. To this end, L. amazonensis were cloned by limiting dilution and the clones' virulence was evaluated by the course of infection in susceptible mice. Clones originally derived from the spleen showed virulence variations in comparison with that of the parental population (PP) of parasites. Two low-virulence clones (SP 5 and SP 20) and one medium-virulence clone (SP 11), representative of the spectrum of derived clones, were compared with virulent parasites and with an avirulent strain (Josefa) as to their ability to induce T-cell immune responses and to protect BALB/c mice from infection with the virulent L. amazonensis PP. Clone SP 20 and clone SP 11 induced partial protection when injected by the intravenous and intradermal route, respectively. The avirulent Josefa strain induced neither T-cell responses nor protection. Low-virulence L. amazonensis clones can therefore be additional tools in vaccine investigation. Received: 22 March 1997 / Accepted: 9 April 1997     

Serum amyloid A-induced mRNA expression and release of tumor necrosis factor-alpha (TNF-alpha) in human neutrophils

Recently, we described the effect of the acute phase protein serum amyloid A (SAA) on the mRNA expression and release of IL-8 in neutrophils [Mediators Inflamm. 12 (3) (2003) 173]. Here, we expand this earlier study, focusing on tumor necrosis factor-alpha (TNF-alpha) m-RNA expression and protein release. Our findings indicate that SAA stimulates the rapid expression and release of TNF-alpha from cultured human blood neutrophils. The release of TNF-alpha from SAA-stimulated neutrophils is strongly suppressed by the addition of the antioxidants N-acetyl-L-cysteine, alpha-mercaptoethanol, glutathione, the antiinflammatory dexamethasone and the compounds wortmannin (a PI3K inhibitor), PD98059 (a MEK-1 inhibitor) and SB203580 (a p38 inhibitor). Monocytes also responded to SAA by releasing TNF-alpha. These data are congruent with the increasing evidence of the role of SAA in modulating inflammatory and immune responses, possibly contributing to the pool of cytokines produced in acute inflammation and in chronic diseases.     

Development of membranes based on carboxymethyl cellulose/acetylated arrowroot starch containing bromelain extract carried on nanoparticles and liposomes

Polymeric membranes have been used in several applications, including their use as curatives in cutaneous wounds. Bromelain has long been used for anti-inflammatory purposes, so the objective of this work was to produce carboxymethylcellulose-acetylated blends, incorporate bromelain, characterize the systems, compare the blends with bromelain loaded in nanoparticles and liposomes and, finally, to evaluate their healing potential. Four membrane formulations were produced by solvent evaporation: the control, membranes containing free bromelain, bromelain-loaded nanoparticles (NPs) and bromelain-loaded liposomes (LIPs). The enzyme concentration was the same for all formulations. Transparent, flexible and intact films were obtained. The membranes containing free bromelain, bromelain-loaded NPs and bromelain-loaded LIPs had higher water content, lower water vapor permeability and maximum tensile strength, and greater elongation at rupture. The capacity to absorb simulated exudate was higher in samples containing free bromelain, and bioadhesion was reduced in the presence of free bromelain compared to the control. An in vivo assay was performed to verify the membranes’ healing potential. Histological analysis revealed no edema on the 14th day in animals treated with membranes containing bromelain-loaded NPs and LIPs.     

Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine

Transport of iodide into thyrocytes, a fundamental step in thyroid hormone biosynthesis, depends on the presence of the sodium-iodide symporter (NIS). The importance of the NIS for diagnosis and treatment of diseases has raised several questions about its physiological control. The goal of this study was to evaluate the influence of thyroid iodine content on NIS regulation by thyrotrophin (TSH) in vivo. We showed that 15-min thyroid radioiodine uptake can be a reliable measurement of NIS activity in vivo. The effect of TSH on the NIS was evaluated in rats treated with 1-methyl-2-mercaptoimidazole (MMI; hypothyroid with high serum TSH concentrations) for 21 days, and after 1 (R1d), 2 (R2d), or 5 (R5d) days of withdrawal of MMI. NIS activity was significantly greater in both MMI and R1d rats. In R2d and R5d groups, thyroid iodide uptake returned to normal values, despite continuing high serum TSH, possibly as a result of the re-establishment of iodine organification after withdrawal of MMI. Excess iodine (0.05% NaI for 6 days) promoted a significant reduction in thyroid radioiodide uptake, an effect that was blocked by concomitant administration of MMI, confirming previous findings that iodine organification is essential for the iodide transport blockade seen during iodine overload. Therefore, our data show that modulation of the thyroid NIS by TSH depends primarily on thyroid iodine content and, further, that the regulation of NIS activity is rapid.