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Virus Suppression (virus + suppression)
Selected AbstractsMULTIPLE HIV-1 INFECTION OF CELLS AND THE EVOLUTIONARY DYNAMICS OF CYTOTOXIC T LYMPHOCYTE ESCAPE MUTANTSEVOLUTION, Issue 9 2009Dominik Wodarz Cytotoxic T lymphocytes (CTL) are an important branch of the immune system, killing virus-infected cells. Many viruses can mutate so that infected cells are not killed by CTL anymore. This escape can contribute to virus persistence and disease. A prominent example is HIV-1. The evolutionary dynamics of CTL escape mutants in vivo have been studied experimentally and mathematically, assuming that a cell can only be infected with one HIV particle at a time. However, according to data, multiple virus particles frequently infect the same cell, a process called coinfection. Here, we study the evolutionary dynamics of CTL escape mutants in the context of coinfection. A mathematical model suggests that an intermediate strength of the CTL response against the wild-type is most detrimental for an escape mutant, minimizing overall virus load and even leading to its extinction. A weaker or, paradoxically, stronger CTL response against the wild-type both lead to the persistence of the escape mutant and higher virus load. It is hypothesized that an intermediate strength of the CTL response, and thus the suboptimal virus suppression observed in HIV-1 infection, might be adaptive to minimize the impact of existing CTL escape mutants on overall virus load. [source] In vivo immunization following virus suppression: a novel approach for inducing immune control in chronic hepatitis B,JOURNAL OF VIRAL HEPATITIS, Issue 1 2003D. Sprengers summary. Antiviral treatment of patients with active chronic hepatitis B may lead to significant reduction in morbidity and mortality. However, after stopping nucleoside therapy, relapse rates are high in those without acquired specific immunity. We have treated two chronic hepatitis B patients with in vivo immunization. In vivo immunization aims to optimize conditions for an effective immune response: following rapid and profound virus suppression by interferon-lamivudine combination therapy, lamivudine is withdrawn intermittently for 4 weeks during continued interferon therapy. In both patients with profound virus suppression a rapid rebound in viral replication was observed after lamivudine withdrawal; despite continued interferon. These periods of renewed viral replication were followed by rises in hepatitis activity. After re-introduction of lamivudine HBV DNA became undetectable by PCR followed by normalization of serum ALT. These observations are a stimulus to further explore the concept of in vivo immunization as a novel therapeutic approach for chronic hepatitis B. [source] Hepatitis B in liver transplant recipientsLIVER TRANSPLANTATION, Issue S2 2006Robert G. Gish Key Concepts: 1The use of low-dose immunosuppressive therapy along with pre- and posttransplantation nucleos(t)ide therapy and posttransplantation hepatitis B immunoglobulin (HBIG) has yielded marked improvements in survival. 2Lamivudine (Epivir-HBV), adefovir (Hepsera), entecavir (Baraclude), tenofovir (Viread), emtricitabine (Emtriva), and the combination drugs tenofovir + emtricitabine (Truvada) and abacavir + lamivudine (Epzicom) are effective nucleos(t)ide antiviral agents that, in some cases, may help reverse liver disease sufficiently to avoid transplant. 3In posttransplantation patients, virus suppression with some combination of HBIG and the nucleos(t)ide agents may prevent graft loss and death or the need for a second transplant. 4In both the pre- and posttransplantation setting, the goal of hepatitis B virus management is complete virus suppression. 5The use of low-dose intramuscular HBIG is evolving, with studies showing that dosing and cost can be reduced by 50,300% with a customized approach. 6Elimination of HBIG from the treatment paradigm is currently under evaluation and may be possible with the use of newer medications that have no or low resistance rates. 7Although there is growing evidence that some types of combination therapy may decrease the chance that drug resistance will develop and increase the likelihood of long-term success in preventing graft loss and death, additional research will be required to determine which combinations will work well in the long term, and which will not. Liver Transpl 12:S54,S64, 2006. © 2006 AASLD. [source] | ||||||||||