Identification of B-cell epitope of dengue virus type 1 and its application in diagnosis of patients.
Using a serotype-specific monoclonal antibody (MAb) of dengue virus type 1 (DEN-1), 15F3-1, we identified the B-cell epitope of DEN-1 from a random peptide library displayed on phage. Fourteen immunopositive phage clones that bound specifically to MAb 15F3-1 were selected. These phage-borne peptides had a consensus motif of HxYaWb (a = S/T, b = K/H/R) that mimicked the sequence HKYSWK, which corresponded to amino acid residues 111 to 116 of the nonstructural protein 1 (NS1) of DEN-1. Among the four synthetic peptides corresponding to amino acid residues 110 to 117 of the NS1 of DEN-1, -2, -3, and -4, only one peptide, EHKYSWKS (P14M) of DEN-1, was found to bind to 15F3-1 specifically. Furthermore, P14M was shown to inhibit the binding of phage particles to 15F3-1 in a competitive inhibition assay. Histidine(111) (His(111)) was crucial to the binding of P14M to 15F3-1, since its binding activity dramatically reduced when it changed to leucine(111) (Leu(111)). This epitope-based peptide demonstrated its clinical diagnostic potential when it reacted with a high degree of specificity with serum samples obtained from both DEN-1-infected rabbits and patients. Based on these observations, our DEN-1 epitope-based serologic test could be useful in laboratory viral diagnosis and in understanding the pathogenesis of DEN-1.
Wu
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HC
Institute of Preventive Medicine, National Defense Medical Center, P.O. Box 90048-700, San-Hsia, Taipei, Taiwan, Republic of China. ipmc3@ms29.hinet.net
Huang
Y L
YL
Chao
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TT
Jan
J T
JT
Huang
J L
JL
Chiang
H Y
HY
King
C C
CC
Shaio
M F
MF
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D001435:Bacteriophages / Q000235:genetics; D003715:Dengue / Q000175:diagnosis* / Q000821:virology; D003716:Dengue Virus / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D006801:Humans; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000737:chemistry
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D018985:Epitopes, B-Lymphocyte; C100315:NS1 protein, Flavivirus; D019151:Peptide Library; D010455:Peptides; D017361:Viral Nonstructural Proteins