Human neutralizing Fab molecules against severe acute respiratory syndrome coronavirus generated by phage display

Clin Vaccine Immunol. 2006 Aug;13(8):953-7. doi: 10.1128/CVI.00037-06.

Abstract

Human recombinant Fab fragments specific for the spike protein of severe acute respiratory syndrome coronavirus (SARS-CoV) were screened from a human Fab library, which was generated from RNAs from peripheral lymphocytes of convalescent SARS patients. Among 50 randomly picked clones, 12 Fabs specially reacted with S protein by an enzyme-linked immunosorbent assay. The microneutralizing test showed that one clone, designated M1A, had neutralizing activity on Vero E6 cells against SARS-CoV. DNA sequence analysis indicated that the light- and heavy-chain genes of M1A Fab belong to the kappa2a and 4f families, respectively. A neutralizing test on purified M1A demonstrated that 0.5 mg/ml of M1A completely inhibited SARS-CoV activity, with an absence of cytopathic effect for 7 days. Real-time fluorescence reverse transcription-PCR also proved the neutralizing capacity of M1A. These data showed that the number of virus copies was significantly reduced in the M1A-treated group, suggesting an important role for M1A in passive immunoprophylaxis against the SARS virus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Viral / genetics
  • Antibodies, Viral / immunology*
  • Antibodies, Viral / isolation & purification
  • Humans
  • Immunoglobulin Fab Fragments / genetics
  • Immunoglobulin Fab Fragments / immunology*
  • Immunoglobulin Fab Fragments / isolation & purification
  • Immunoglobulin Variable Region / immunology
  • Immunologic Factors / chemistry
  • Immunologic Factors / immunology
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Peptide Library*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Severe Acute Respiratory Syndrome / immunology*
  • Severe acute respiratory syndrome-related coronavirus / immunology*

Substances

  • Antibodies, Viral
  • Immunoglobulin Fab Fragments
  • Immunoglobulin Variable Region
  • Immunologic Factors
  • Peptide Library