Phage antibodies obtained by competitive selection on complement-resistant Moraxella (Branhamella) catarrhalis recognize the high-molecular-weight outer membrane protein.
We used competitive panning to select a panel of 10 different human antibodies from a large semisynthetic phage display library that distinguish between serum complement-resistant and complement-sensitive strains of the gram-negative diplococcus Moraxella (Branhamella) catarrhalis. Western blotting analyses and inhibition enzyme-linked immunosorbent assays showed that all phage antibodies were directed against the same or closely spaced epitopes on the target protein, which is the high-molecular-weight outer membrane protein (HMW-OMP) of M. catarrhalis. HMW-OMP was found in multiple isolates of complement-resistant but not complement-sensitive M. catarrhalis strains. Nucleotide sequence analysis demonstrated that the immunoglobulin heavy- and light-chain variable-region genes encoding the 10 phage antibodies were remarkably similar, with a strong preference for basic amino acid residues in the heavy-chain CDR3 regions. This is the first report showing that competitive panning is a successful procedure to obtain phage antibodies against differentially expressed structures on phenotypically dissimilar strains of prokaryotic cells.
Boel
E
E
Eijkman-Winkler Institute for Microbiology, Infectious Diseases, and Inflammation, Utrecht University Hospital, The Netherlands. eboel@pi.net
Bootsma
H
H
de Kruif
J
J
Jansze
M
M
Klingman
K L
KL
van Dijk
H
H
Logtenberg
T
T
D000914:Antibodies, Viral / Q000235:genetics / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001435:Bacteriophages / Q000235:genetics / Q000276:immunology*; D015153:Blotting, Western; D003165:Complement System Proteins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology; D001936:Moraxella catarrhalis / Q000276:immunology* / Q000821:virology*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
D000914:Antibodies, Viral; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D003165:Complement System Proteins