Method for generating and selecting antibodies against target protein
Methods and compositions are provided for efficient, high throughput screening of antibody libraries against proteins targets, especially membrane proteins in yeast. In particular, methods are provided for screening a diverse antibody library for antibodies that bind to a membrane protein such as a chemokine receptor in yeast.
1. A method for displaying a library of antibodies on the surface of yeast cells, comprising:
providing yeast cells transformed with a library of yeast expression vectors encoding a library of antibodies each comprising an antibody heavy chain variable region (V H ) and an antibody light chain variable region (V L ), wherein at least one yeast expression vector comprises one or more homologous recombination sites and has undergone homologous recombination such that an insert polynucleotide sequence from a first polynucleotide sequence encoding the V H or a second polynucleotide sequence encoding the V L is incorporated into the yeast expression vector, and wherein the V H or V L polynucleotide sequence is fused in-frame with a sequence encoding a binding subunit of a yeast adhesion receptor; and
expressing the library of antibodies encoded by the library of yeast expression vectors in the yeast cells, whereby the library of antibodies are displayed on the surface of the yeast cells.
2. The method of claim 1 , wherein the yeast cells are Saccharomyces cerevisiae cells.
3. The method of claim 1 , wherein the yeast adhesion receptor is a-agglutinin or α-agglutinin.
4. The method of claim 1 , wherein the library of yeast expression vectors are constructed by homologous recombination in yeast cells between a linearized yeast expression vector and a library of insert nucleotide sequences that are linear and double-stranded, each insert sequence comprising a nucleotide sequence encoding V H or V L .
5. The method of claim 1 , wherein a region of the V H or V L is mutagenized.
6. The method of claim 5 , wherein the region of the V H or V L is mutagenized through mutagenesis selected from the group consisting of error-prone PCR mutagenesis, site-directed mutagenesis, cassette mutagenesis, DNA shuffling and combinations thereof.
7. The method of claim 1 , wherein the diversity of the library of antibodies is at least 1×10 6 .
8. The method of claim 1 , wherein the diversity of the library of antibodies is at least 1×10 7 .
9. The method of claim 1 , wherein the diversity of the library of antibodies is at least 1×10 7 −1×10 10 .
10. The method of claim 1 , wherein the diversity of the library of antibodies is at least 1×10 8 −1×10 10 .
11. The method of claim 1 , wherein the sequence of the antibody heavy or light chain variable region is fully human.
12. The method of claim 1 , wherein the V H and V L are encoded by variable regions of immunoglobulin genes of a human, non-human primate, or rodent.
13. The method of claim 1 , wherein the V H and V L are encoded respectively by a heavy-chain variable region and a light-chain variable region of a human immunoglobulin gene.
14. The method of claim 1 , wherein the VH is encoded by a heavy-chain variable region of a first human immunoglobulin gene, and the VL is encoded by a light chain variable region of a second human immunoglobulin gene different from the first human immunoglobulin gene.
15. The method of claim 1 , wherein the antibody heavy or light chain variable region is encoded by a human IgG gene.