1,721,630 research outputs found
New perspectives for T-cell-based HCV vaccines
No full textA T-cell HCV vaccine eliciting effective immunity against heterologous virus challenge in chimpanzees. Folgori A, Capone S, Ruggeri L, Meola A, Sporeno E, Ercole BB, Pezzanera M, Tafi R, Arcuri M, Fattori E, Lahm A, Luzzago A, Vitelli A, Colloca S, Cortese R, Nicosia A. Three percent of the world's population is chronically infected with the hepatitis C virus (HCV) and at risk of developing liver cancer. Effective cellular immune responses are deemed essential for spontaneous resolution of acute hepatitis C and long-term protection. Here, we describe a new T-cell HCV genetic vaccine capable of protecting chimpanzees from acute hepatitis induced by challenge with heterologous virus. Suppression of acute viremia in vaccinated chimpanzees occurred as a result of massive expansion of peripheral and intrahepatic HCV-specific CD8(+) T lymphocytes that cross-reacted with vaccine and virus epitopes. These findings show that it is possible to elicit effective immunity against heterologous HCV strains by stimulating only the cellular arm of the immune system, and suggest a path for new immunotherapy against highly variable human pathogens like HCV, HIV or malaria, which can evade humoral responses. [Abstract reproduced by permission of Nat Med 2006;12(2):190-197]. © 2006 European Association for the Study of the Liver
HBV and the immune response
No full textHepatitis B virus (HBV) infection acquired in adult life is generally self-limited while chronic persistence of the virus is the prevalent outcome when infection is acquired perinatally. Both control of infection and liver cell injury are strictly dependent upon protective immune responses, because hepatocyte damage is the price that the host must pay to get rid of intracellular virus. Resolution of acute hepatitis B is associated with functionally efficient, multispecific antiviral T-cell responses which are preceded by a poor induction of intracellular innate responses at the early stages of infection. Persistent control of infection is provided by long-lasting protective memory, which is probably sustained by continuous stimulation of the immune system by trace amounts of virus which are never totally eliminated, persisting in an occult episomic form in the nucleus of liver cells even after recovery from acute infection. Chronic virus persistence is instead characterized by a lack of protective T-cell memory maturation and by an exhaustion of HBV-specific T-cell responses. Persistent exposure of T cells to high antigen loads is a key determinant of functional T-cell impairment but also other mechanisms can contribute to T-cell inhibition, including the tolerogenic effect of the liver environment. The degree of T-cell impairment is variable and its severity is related to the level of virus replication and antigen load. The antiviral T-cell function is more efficient in patients who can control infection either partially, such as inactive HBsAg carriers with low levels of virus replication, or completely, such as patients who achieve HBsAg loss either spontaneously or after antiviral therapy. Thus, understanding the features of the immune responses associated with control of infection is needed for the successful design of novel immune modulatory therapies based on the reconstitution of efficient antiviral responses in chronic HBV patients
Planning Optimal Grasps
Full text linkThe authors address the problem of planning optimal grasps. Two general optimality criteria that consider the total finger force and the maximum finger force are introduced and discussed. Their formalization using various metrics on a space of generalized forces is detailed. The geometric interpretation of the two criteria leads to an efficient planning algorithm. An example of its use in a robotic environment equipped with two-jaw and three-jaw is describe
Efficient Algorithms for Collision Detection Between Rigid Bodies in the Simulation of a Dynamic Scene
No full textMortality from HIV and TB coinfections is higher in Eastern Europe than in Western Europe and Argentina
No full textBACKGROUND AND OBJECTIVES: Tuberculosis (TB) is a leading cause of death in HIV-infected patients worldwide. We aimed to study clinical characteristics and outcome of 1075 consecutive patients diagnosed with HIV/TB from 2004 to 2006 in Europe and Argentina. METHODS: One-year mortality was assessed in patients stratified according to region of residence, and factors associated with death were evaluated in multivariable Cox models. RESULTS: At TB diagnosis, patients in Eastern Europe had less advanced immunodeficiency, whereas a greater proportion had a history of intravenous drug use, coinfection with hepatitis C, disseminated TB, and infection with drug-resistant TB (P < 0.0001). In Eastern Europe, fewer patients initiated TB treatment containing at least rifamycin, isoniazid, and pyrazinamide or combination antiretroviral therapy (P < 0.0001). Mortality at 1 year was 27% in Eastern Europe, compared with 7, 9 and 11% in Central/Northern Europe, Southern Europe, and Argentina, respectively (P < 0.0001). In a multivariable model, the adjusted relative hazard of death was significantly lower in each of the other regions compared with Eastern Europe: 0.34 (95% confidence interval 0.17-0.65), 0.28 (0.14-0.57), 0.34 (0.15-0.77) in Argentina, Southern Europe and Central/Northern Europe, respectively. Factors significantly associated with increased mortality were CD4 cell count less than 200 cells/μl [2.31 (1.56-3.45)], prior AIDS [1.74 (1.22-2.47)], disseminated TB [2.00 (1.38-2.85)], initiation of TB treatment not including rifamycin, isoniazid and pyrazinamide [1.68 (1.20-2.36)], and rifamycin resistance [2.10 (1.29-3.41)]. Adjusting for these known confounders did not explain the increased mortality seen in Eastern Europe. CONCLUSION: The poor outcome of patients with HIV/TB in Eastern Europe deserves further study and urgent public health attention. © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Context-Dependent Reputation Management for Soft Security in MultiAgent Systems
No full textMobile Agent Systems lack of security tools to grant access to their services to a wide range of users as open systems should do. A major issue is to prevent interactions with malicious entities. Trust concept from social science can help information systems to obtain solid social network of collaboration. We propose a flexible reputation framework with a centralized approach that manages trustworthiness of entities grouped by trust context. Members of each group share context-dependent trust opinions within the group itself, in order to form a knowledge base of reputation information. A common ontology supports generic communication, e.g. opinion sharing, and a context-dependent specific ontology is used for opinion formations. The reputations are the weighted means of opinions provided by trusted entities. That information supports the decision making and risk evaluation processes anytime entities start new relations
Management of parkings in a metropolitan area
No full textOutdoor Ambient Assisted Living at a metropolitan area level,
requires to develop highly scalable systems that are
tolerant with respect to many different types of faults. The software components
that are immersed in the environment and that form the fixed infrastructural
part of the system, have to be strongly coupled with all the mobile and volatile
components in order to obtain collective cooperative processes that let the
environment to transparently show some degree of intelligent behavior.
In this paper, we aim at presenting a system for the intelligent management
of the parking requests that come in a metropolitan area. In order to deal with
all issues that arise from mobile devices and to emphasize software partition
as a key methodology in AmI, we designed the parking system using the agent paradigm. Due to the general organization of a metropolitan area, we introduced a hierarchical
model to better deal with all the details at different levels of abstractions.
The agent-based software structure reflects the topographic hierarchy: the system
workflow is then detailed using cooperative processes between agents, that are build
on protocolled interactions that are based on message exchanges and agent mobility.
A first prototype has been developed. The infrastructural part has been simulated andreal mobile device, namely HTC-Android smartphones, have been used. JADE and its
plug-in for mobile device JADE-LEAP, has been used as the platform for agents
- …
