title: Characterization of an isotype-dependent monoclonal antibody against linear neutralizing epitope effective for prophylaxis of enterovirus 71 infection.
abstract: BACKGROUND
  Enterovirus 71 (EV71) is the main causative agent of Hand, Foot and Mouth disease (HFMD) and is associated with severe neurologic complications and mortalities. At present, there is no vaccine or therapeutic available for treatment.
  
  
  RESULTS
  In this study, we generated two mAbs, denoted as mAb 51 and 53, both targeting the same linear epitope on VP1 capsid protein, spanning amino acids 215-219. In comparison, mAb 51 belonging to isotype IgM possesses neutralizing activity in vitro, whereas, mAb 53 belonging to isotype IgG1 does not have any neutralizing ability, even towards its homologous strain. When mAb 51 at 10 µg/g of body weight was administered to the 2-week-old AG129 mice one day prior to lethal challenge, 100% in vivo passive protection was observed. In contrast, the isotype control group mice, injected with an irrelevant IgM antibody before the challenge, developed limb paralysis as early as day 6 post-infection. Histological examination demonstrated that mAb 51 was able to protect against pathologic changes such as neuropil vacuolation and neuronal loss in the spinal cord, which were typical in unprotected EV-71 infected mice. BLAST analyses of that epitope revealed that it was highly conserved among all EV71 strains, but not coxsachievirus 16 (CA16).
  
  
  CONCLUSIONS
  We have defined a linear epitope within the VP1 protein and demonstrated its neutralizing ability to be isotype dependent. The neutralizing property and highly conserved sequence potentiated the application of mAb 51 and 53 for protection against EV71 infection and diagnosis respectively.
authors.affiliation: Animal Health Biotechnology, Temasek Life Sciences Laboratory, Singapore.
authors.forename: Xiao Fang
authors.initials: XF
authors.lastname: Lim
authors.forename: Qiang
authors.initials: Q
authors.lastname: Jia
authors.forename: Wei Xin
authors.initials: WX
authors.lastname: Khong
authors.forename: Benedict
authors.initials: B
authors.lastname: Yan
authors.forename: Balraj
authors.initials: B
authors.lastname: Premanand
authors.forename: Sylvie
authors.initials: S
authors.lastname: Alonso
authors.forename: Vincent T K
authors.initials: VT
authors.lastname: Chow
authors.forename: Jimmy
authors.initials: J
authors.lastname: Kwang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D015153:Blotting, Western; D036022:Capsid Proteins / Q000276:immunology / Q000378:metabolism; D002522:Chlorocebus aethiops; D029821:Enterovirus A, Human / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D004769:Enterovirus Infections / Q000276:immunology* / Q000517:prevention & control; D018604:Epitope Mapping / Q000379:methods; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007114:Immunization / Q000379:methods; D007132:Immunoglobulin Isotypes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014709:Vero Cells
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D036022:Capsid Proteins; D000939:Epitopes; D007132:Immunoglobulin Isotypes; D012367:RNA, Viral