Publications by authors named "Laurie Ngo"

Mumps virus (MuV) is a neurotropic non-segmented, negative-stranded, enveloped RNA virus in the family. The 15.4 kb genome encodes seven genes, including the V/P, which encodes, among other proteins, the V protein.

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Mumps virus (MuV) is postulated to adhere to the "rule of six" for efficient replication. To examine the requirement for MuV, minigenomes of nonpolyhexameric length (6n-1 and 6n+1) were analyzed. Expression of the reporter gene CAT was significantly reduced with minigenomes of nonpolyhexameric length compared to the wild type 6n genome, and reduction was more pronounced for the 6n-1 than for the 6n+1 minigenome.

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Mumps is a highly infectious viral disease of humans with a wide array of clinical manifestations ranging from painful swelling of the salivary glands to meningitis and encephalitis. Despite the clinical importance of mumps virus, most of what is known of its biological properties comes from studies using supernatants from virus infected cell cultures, which contain substantial levels of host cell derived debris and biologically active substances such as cytokines, transcription factors and secreted virus proteins. These contaminants complicate interpretation of studies of virus replication, virus-host interactions and in vivo virulence.

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As a member of the family paramyxoviridae, subfamily paramyxovirinae, the genome of mumps virus (MuV) is postulated to be polyhexameric in length in order to be able to replicate efficiently. While all natural MuV strains sequenced so far obey to this "rule of six," we describe here the isolation of recombinant MuVs that appeared to contain an additional U residue in the homopolymeric tract of the F gene-end signal, resulting in a genome length of 6n + 1. Sequencing of several plaque-purified viruses from these preparations did not reveal the existence of length-correcting mutations, suggesting that they are violators of the rule of six.

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Article Synopsis
  • - The study investigates whether a third dose of the MMR vaccine (MMR3) is necessary in populations with high vaccination rates, focusing on mumps antibody levels in young adults aged 18-28.
  • - Prior to receiving MMR3, only a small percentage of participants had low or negative mumps antibody levels, and these numbers improved slightly one year after the vaccination.
  • - Although there was a significant increase in antibody levels post-MMR3, the overall improvements were modest and may only provide short-term protection during mumps outbreaks rather than being beneficial for regular vaccination strategies.
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Recently, numerous large-scale mumps outbreaks have occurred in vaccinated populations. Clinical isolates sequenced from these outbreaks have invariably been of genotypes distinct from those of vaccine viruses, raising concern that certain mumps virus strains may escape vaccine-induced immunity. To investigate this concern, sera obtained from children 6 weeks after receipt of measles, mumps, and rubella (MMR) vaccine were tested for the ability to neutralize a carefully selected group of genetically diverse mumps virus strains.

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Background: In 2006, a mumps outbreak occurred on a university campus despite ≥ 95% coverage of students with 2 doses of measles-mumps-rubella (MMR) vaccine. Using plasma samples from a blood drive held on campus before identification of mumps cases, we compared vaccine-induced preoutbreak mumps antibody levels between individuals who developed mumps (case patients) and those who did not develop mumps (nonpatients).

Methods: Preoutbreak samples were available from 11 case patients, 22 nonpatients who reported mumps exposure but no mumps symptoms, and 103 nonpatients who reported no known exposure and no symptoms.

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Mumps virus (MuV) is highly neurotropic and was the leading cause of aseptic meningitis in the Western Hemisphere prior to widespread use of live attenuated MuV vaccines. Due to the absence of markers of virus neuroattenuation and neurovirulence, ensuring mumps vaccine safety has proven problematic, as demonstrated by the occurrence of aseptic meningitis in recipients of certain vaccine strains. Here we examined the genetic basis of MuV neuroattenuation and neurovirulence by generating a series of recombinant viruses consisting of combinations of genes derived from a cDNA clone of the neurovirulent wild-type 88-1961 strain (r88) and from a cDNA clone of the highly attenuated Jeryl Lynn vaccine strain (rJL).

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Deletion of the small hydrophobic (SH) protein of certain paramyxoviruses has been found to result in attenuation, suggesting that the SH protein is a virulence factor. To investigate the role of the mumps virus (MuV) SH protein in virulence, multiple stop codons were introduced into the open reading frame (ORF) of a MuV molecular clone (r88-1961(SHstop)), preserving genome structure but precluding production of the SH protein. No differences in neurovirulence were seen between the wild-type and the SH(stop) viruses.

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