Human neutralizing Fab molecules against severe acute respiratory syndrome coronavirus generated by phage display.
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.
Kang
Xiaoping
X
State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
Yang
Bao-An
BA
Hu
Yuyang
Y
Zhao
Hui
H
Xiong
Wei
W
Yang
Yinhui
Y
Si
Bingyin
B
Zhu
Qingyu
Q
D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007135:Immunoglobulin Variable Region / Q000276:immunology; D007155:Immunologic Factors / Q000737:chemistry / Q000276:immunology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D019151:Peptide Library; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology*
D000914:Antibodies, Viral; D007140:Immunoglobulin Fab Fragments; D007135:Immunoglobulin Variable Region; D007155:Immunologic Factors; D019151:Peptide Library