نتایج جستجو برای: vaccine escape mutations
تعداد نتایج: 308143 فیلتر نتایج به سال:
Hepatitis B vaccination is safe and effective, although breakthrough infection occasionally occurs in those who receive the vaccine and hepatitis B immunoglobulin (HBIg) prophylaxis. Sequence variation in their antigenic regions is one of the most powerful strategies that are used by viruses to escape recognition by B and T cell-mediated immune responses. The aim of this study was to explore th...
Perinatal transmission of hepatitis B virus (HBV) has been controlled incompletely despite adequate immunoprophylaxis in infants. The aim of this study was to characterize virological factors of HBV associated with vaccine failure in Thailand. Sera of 14 infected infants (13 HBeAg-positive and one HBeAg-negative) with vaccine failure and their respective mothers (group M1) were tested quantitat...
Antiviral CD8(+) T cells are a key component of the adaptive immune system against hepatitis C virus (HCV). For the development of immune therapies, it is essential to understand how CD8(+) T cells contribute to clearance of infection and why they fail so often. A mechanism for secondary failure is mutational escape of the virus. However, some substitutions in viral epitopes are associated with...
Middle East respiratory syndrome coronavirus (MERS-CoV) binds to cellular receptor dipeptidyl peptidase 4 (DPP4) via the spike (S) protein receptor-binding domain (RBD). The RBD contains critical neutralizing epitopes and serves as an important vaccine target. Since RBD mutations occur in different MERS-CoV isolates and antibody escape mutants, cross-neutralization of divergent MERS-CoV strains...
The sequence diversity of human immunodeficiency virus type 1 (HIV-1) represents a major obstacle to the development of an effective vaccine, yet the forces impacting the evolution of this pathogen remain unclear. To address this issue we assessed the relationship between genome-wide viral evolution and adaptive CD8+ T-cell responses in four clade B virus-infected patients studied longitudinall...
BACKGROUND The direct effect of antigenic site mutations in influenza viruses on antigenic drift and vaccine effectiveness is poorly understood. OBJECTIVE To investigate the genetic and antigenic characteristics of human influenza A (H3N2) viruses circulating in Ontario during the early 2010-2011 winter season. STUDY DESIGN We sequenced the hemagglutinin (HA) and neuraminidase (NA) genes fr...
Following transmission, HIV-1 adapts in the new host by acquiring mutations that allow it to escape from the host immune response at multiple epitopes. It also reverts mutations associated with epitopes targeted in the transmitting host but not in the new host. Moreover, escape mutations are often associated with additional compensatory mutations that partially recover fitness costs. It is uncl...
BACKGROUND Antigen-specific CTL responses are thought to play a central role in containment of HIV-1 infection, but no consistent correlation has been found between the magnitude and/or breadth of response and viral load changes during disease progression. METHODS AND FINDINGS We undertook a detailed investigation of longitudinal CTL responses and HIV-1 evolution beginning with primary infect...
Since its identification as the pathogenic cause of Acquired Immunodeficiency Syndrome (AIDS) in the early 1980s, Human Immunodeficiency Virus Type 1 (HIV) has emerged as a major global pandemic with an estimated 33 million infected individuals worldwide at the end of 2007 [1]. Specifically targeting the so-called “helper T cells” that help coordinate the adaptive immune response, HIV causes a ...
OBJECTIVE S The aim of this study was to determine the correlation between vaccine therapy and appearance of mutations in hepatitis B surface antigen (HBsAg)-positive chronic hepatitis B virus (HBV) patients. MATERIALS AND METHODS 16 patients received the HBV vaccine and another 16 individuals from the control group did not. The surface gene was amplified and directly sequenced from samples p...
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