Identification of a human monoclonal Fab with neutralizing activity against H3N2 influenza A strain from a newly constructed human Fab library.
A combinatorial Fab library was constructed in pComb3H phagemid vectors, using RNA from peripheral blood lymphocytes of a healthy volunteer who had recovered from an influenza A virus infection. The library contained approximately 1.3 x 10(8)E. coli transformants. Bio-panning was carried out against an influenza vaccine containing components of influenza A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2), and B/Shandong/7/97 for the enrichment of phages displaying human Fab specific to the viral proteins. E. coli transformed with IF1A11, 1 of 94 randomly selected clones, displayed a human Fab antibody molecule (FabIF1A11) with efficient neutralizing activity against H3N2 influenza A virus strains. The purified FabIF1A11 demonstrated neutralizing activity against A/Okayama/6/01 (H3N2) and A/Kitakyushu/159/93 (H3N2) with 50% plaque reduction neutralization titers of 0.11 microg/ml (2.2 nM) and 1.4 microg/ml (28 nM) respectively. However, FabIF1A11 did not show neutralizing activity against the influenza A virus strain A/USSR/77 (H1N1) or the influenza B virus strain B/Kanagawa/73, even at a concentration of 20 microg/ml (400 nM). The Kd of FabIF1A11 was calculated as 3.6 x 10(-9) M. FabIF1A11 was estimated to recognize a conformational epitope on the hemagglutinin of A/Okayama/6/01 (H3N2). The human monoclonal Fab product FabIF1A11 may have potential as a therapeutic or short-term prophylactic molecule for humans with influenza A H3N2 infection.
Shibuya
Tadamasa
T
Department of Infectious Diseases, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
Yamashiro
Tetsu
T
Masaike
Yuka
Y
Ohuchi
Masanobu
M
Uechi
Gen-ichiro
G
Nishizono
Akira
A
D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000276:immunology* / Q000302:isolation & purification*; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology* / Q000302:isolation & purification*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology; D007251:Influenza, Human / Q000517:prevention & control; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D019151:Peptide Library; D010948:Viral Plaque Assay
D000914:Antibodies, Viral; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; D019151:Peptide Library