Recombinant library screening methods
First Claim
1. A method for screening a DNA library for nucleotide sequences which encode an antibody Fab fragment comprising first and second polypeptide chains, one chain comprising a light chain variable region and another chain comprising a heavy chain variable region, wherein said antibody Fab fragment binds specifically to a ligand of interest, said method comprising:
- (a) transforming a host cell with a filamentous bacteriophage expression vector selected from the group consisting of fl, fd, and M13 filamentous bacteriophage expression vectors, which vector comprises;
(i) a first nucleotide sequence that encodes a fusion coat protein composed of the first chain fused to a pIII coat protein of the bacteriophage; and
(ii) a second nucleotide sequence that encodes the second chain fused to a signal peptide that directs periplasmic secretion of said second chain;
(b) cultivating the transformed host cell under conditions suitable for expression and assembly of a bacteriophage particle with a coat comprising said fusion coat protein bound to said second chain to form said antibody Fab fragment on the coat of said particle; and
(c) selecting a bacteriophage particle encoding the antibody Fab fragment that binds specifically to the ligand of interest by binding said particle to the ligand specific for said antibody Fab fragment and removing particles that do not bind to said ligand.
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Abstract
Nucleotide sequences encoding proteins of interest are isolated from DNA libraries using bacteriophage to link the protein to the sequence which encodes it. DNA libraries are prepared from cells encoding the protein of interest and inserted into or adjacent to a coat protein of a bacteriophage vector, or into a sequence encoding a protein which may be linked by means of a ligand to a phage coat protein. By employing affinity purification techniques the phage particles containing sequences encoding the desired protein may be selected and the desired nucleotide sequences obtained therefrom. Thus, for example, novel proteins such as monoclonal antibodies may be produced and conventional hybridoma technology avoided.
893 Citations
17 Claims
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1. A method for screening a DNA library for nucleotide sequences which encode an antibody Fab fragment comprising first and second polypeptide chains, one chain comprising a light chain variable region and another chain comprising a heavy chain variable region, wherein said antibody Fab fragment binds specifically to a ligand of interest, said method comprising:
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(a) transforming a host cell with a filamentous bacteriophage expression vector selected from the group consisting of fl, fd, and M13 filamentous bacteriophage expression vectors, which vector comprises; (i) a first nucleotide sequence that encodes a fusion coat protein composed of the first chain fused to a pIII coat protein of the bacteriophage; and (ii) a second nucleotide sequence that encodes the second chain fused to a signal peptide that directs periplasmic secretion of said second chain; (b) cultivating the transformed host cell under conditions suitable for expression and assembly of a bacteriophage particle with a coat comprising said fusion coat protein bound to said second chain to form said antibody Fab fragment on the coat of said particle; and (c) selecting a bacteriophage particle encoding the antibody Fab fragment that binds specifically to the ligand of interest by binding said particle to the ligand specific for said antibody Fab fragment and removing particles that do not bind to said ligand. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification