Development of a humanized monoclonal antibody (MEDI-493) with potent in vitro and in vivo activity against respiratory syncytial virus

J Infect Dis. 1997 Nov;176(5):1215-24. doi: 10.1086/514115.


Neutralizing polyclonal antibody to respiratory syncytial virus (RSV) has been shown to be an effective prophylactic agent when administered intravenously in high-risk infants. This study describes the generation of a humanized monoclonal antibody, MEDI-493, that recognizes a conserved neutralizing epitope on the F glycoprotein of RSV. The affinity of MEDI-493 was found to be equal to or slightly better than an isotype-matched chimeric derivative of the parent antibody. In plaque reduction, microneutralization, and fusion-inhibition assays, MEDI-493 was significantly more potent than the polyclonal preparation. Broad neutralization of a panel of 57 clinical isolates of the RSV A and B subtypes was demonstrated. Pretreatment of cotton rats with MEDI-493 resulted in 99% reduction of lung RSV titers at a dose of 2.5 mg/kg, corresponding to a serum concentration of 25-30 microg/mL. Further, MEDI-493 did not induce increased RSV infection or pathology in either a primary or a secondary challenge.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibodies, Viral / immunology*
  • HN Protein*
  • Humans
  • Molecular Sequence Data
  • Respiratory Syncytial Virus Infections / prevention & control*
  • Respiratory Syncytial Virus, Human / immunology*
  • Sigmodontinae
  • Viral Envelope Proteins
  • Viral Proteins / immunology*


  • Antibodies, Monoclonal
  • Antibodies, Viral
  • HN Protein
  • Viral Envelope Proteins
  • Viral Proteins
  • attachment protein G