title: Mumps outbreaks in a highly vaccinated population: Investigation of a neutralization titre against the current circulating wildtype genotype G5 mumps virus.
abstract: BACKGROUND
  Mumps outbreaks continue to occur globally, despite high levels of uptake of the mumps vaccine.
  
  
  OBJECTIVE
  In order to address immunity to the current circulating wildtype virus, we sought to determine a mumps G5 specific IgG quantitative value which correlates with genotype G5 specific neutralization ability in vitro.
  
  
  METHODS
  Sera from 199 individuals including controls and acute mumps cases were assessed for mumps specific IgG titres using five different enzyme immunoassays coated with antigen from different mumps virus strains. A subset of 66 sera was also assessed for in vitro neutralizing antibody against a contemporary circulating genotype G5 mumps virus.
  
  
  RESULTS
  For all the different antigenic targets, mumps specific IgG titres were higher in patients following acute mumps infection compared to controls. In acute mumps infected patients, females showed significantly higher serum titres of anti-G5 IgG compared to males (p<0.05). Furthermore, control males did not show any change in G5 specific IgG with increasing age whereas females show a progressive rise in titre. Linear regression analysis revealed a significant association between the mumps G5 specific IgG levels in the EIA and the in vitro neutralization titres (r(2)=0.59).
  
  
  CONCLUSIONS
  Specific IgG to the current circulating genotype G5 mumps strain showed significantly lower titres in males which supports our previous observation that there is a male gender bias in cases of acute mumps infection. Furthermore, in this preliminary study, the data indicate that genotype G5 specific IgG levels of >40 RU/ml are required for neutralization capability to be observed in vitro.
authors.affiliation: National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Lena
authors.initials: L
authors.lastname: Kenny
authors.affiliation: National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Edwin
authors.initials: E
authors.lastname: O'Kelly
authors.affiliation: National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Jeff
authors.initials: J
authors.lastname: Connell
authors.affiliation: National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Cillian
authors.initials: C
authors.lastname: De Gascun
authors.affiliation: National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland. Electronic address: jaythoon.hassan@ucd.ie.
authors.forename: Jaythoon
authors.initials: J
authors.lastname: Hassan
mesh_terms: D000293:Adolescent; D000328:Adult; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D005838:Genotype; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D008875:Middle Aged; D009107:Mumps / Q000453:epidemiology* / Q000276:immunology / Q000821:virology*; D009109:Mumps virus / Q000145:classification / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007074:Immunoglobulin G
keywords: G5 mumps virus; Gender bias; Mumps outbreaks; Mumps virus-specific IgG; Neutralization