RADICALLY DIVERSE HUMAN ANTIBODY LIBRARY
Disclosed is an antibody library comprising a plurality of antibodies with non-naturally occurring combinations of complementary determining regions from memory and naïve B-cells naturally occurring in humans, and wherein the antibody library comprises a high number of functional and non-redundant antibodies. Further disclosed are methods of preparing antibody libraries with a high level of functional diversity.
1 . A method of preparing an antibody library, comprising:
a) obtaining sequence information for a plurality of VH-CDR3 and VL-CDR3 sequences from a pool of naïve B-cells and sequence information for a plurality of VH-CDR1, VH-CDR2, VH-CDR3, VL-CDR1, VL-CDR2, and VL-CDR3 sequences from a pool of memory B-cells;
b) assembling a plurality of variable light (VL) domain sequences, each VL domain sequence comprising: a VL-CDR1 sequence derived from the sequence information from memory B-cells determined in part a), a VL-CDR2 sequence derived from the sequence information from memory B-cells determined in part a), and a VL-CDR3 sequence derived from the sequence information from memory B-cells or naïve B-cells determined in part a),
c) assembling a first plurality of nucleic acid sequences encoding a first plurality of antibodies, each antibody comprising:
i. a variable light (VL) domain sequence assembled in part b); and
ii. a single fixed heavy chain sequence;
d) inserting the first plurality of nucleic acid sequences into a first plurality of phages;
e) transforming a plurality of microbes with the first plurality of phages to produce a first plurality of transformants, wherein the first plurality of transformants express the first plurality of antibodies on the surface of a second plurality of phages;
f) applying at least one selective pressure to the second plurality of phages;
g) screening the second plurality of phages for expression of an antibody with an ability to bind to a protein to produce a subset of the second plurality of phages comprising a subset of the first plurality of nucleic acid sequences;
h) assembling a plurality of a variable heavy (VH) domain sequences, each VH domain sequence comprising: a VH-CDR1 sequence derived from the sequence information from memory B-cells determined in part a), a VH-CDR2 sequence derived from the sequence information from memory B-cells determined in part a), and a VH-CDR3 sequence derived from the sequence information from memory B-cells or naïve B-cells determined in part a), wherein at least one of the VH-CDR3 sequence and the VL-CDR3 sequence is derived from the sequence information from naïve B-cells;
i) replacing the single fixed heavy chain sequences of the subset of the first plurality of nucleic acid sequences with the plurality of VH domain sequences assembled in part h) to produce a second plurality of nucleic acid sequences, each nucleic acid sequence comprising:
i. a variable light (VL) domain sequence assembled in step b), and
ii. a variable heavy (VH) domain sequence assembled in step h),
wherein the second plurality of nucleic acid sequences encodes a second plurality of antibodies;
j) inserting the second plurality of nucleic acid sequences into a third plurality of phages; and
k) transforming a plurality of microbes with the third plurality of phages to produce a second plurality of transformants, wherein the plurality of second transformants express the second plurality of antibodies on the surface of a fourth plurality of phages.
2 . The method of claim 1 , wherein the pool of naïve B-cells comprises less than 5% of cells not of naïve B-cell origin, and the pool of memory B-cells comprises less than 5% of cells not of memory B-cell origin.
3 . The method of claim 1 , wherein the at least one of the VH-CDR3 sequence and the VL-CDR3 sequence derived from a naïve B-cell is a naturally occurring sequence.
4 . The method of claim 1 , wherein the VH-CDR3 sequence or VL-CDR3 sequence derived from a memory cell is a naturally occurring sequence, and wherein the VH-CDR1 sequence, VH-CDR2 sequence, VL-CDR1 sequence, and VL-CDR2 sequence derived from a memory B cell are naturally occurring sequences.
5 . The method of claim 1 , wherein the at least one of the VH-CDR3 sequence and the VL-CDR3 sequence derived from a naïve B-cell comprises at least 80% sequence homology to a naturally occurring sequence.
6 . The method of claim 1 , wherein the VH-CDR3 sequence or VL-CDR3 sequence derived from a memory cell comprises at least 80% sequence homology to a naturally occurring sequence, and wherein the VH-CDR1 sequence, VH-CDR2 sequence, VL-CDR1 sequence, and VL-CDR2 sequence derived from a memory B cell comprise at least 80% sequence homology to a naturally occurring sequence.
7 . The method of claim 1 , wherein the pool of naïve B-cells, the pool of memory cells, or the combination thereof is obtained from a plurality of individuals.
8 . The method of claim 1 , further comprising sorting the naïve B-cells and memory B-cells in a sample to produce the pool of naïve B-cells and the pool of memory B-cells prior to obtaining the sequence information.
9 . The method of claim 8 , wherein sorting the naïve B-cells and the memory B-cells comprises flow cytometry.
10 . The method of claim 1 , wherein the method further comprises extracting nucleic acid from the naïve B-cells and the memory B-cells.
11 . The method of claim 10 , wherein the nucleic acid is DNA or mRNA.
12 . The method of claim 1 , wherein assembling each VL domain sequence comprises the use of overlap extension PCR (OE-PCR).
13 . The method of claim 1 , wherein assembling each VH domain sequence comprises the use of overlap extension PCR (OE-PCR).
14 . The method of claim 1 , wherein the single fixed heavy chain sequence is a germline sequence selected from the group consisting of: IGHJ4, IGHV1-46, IGHV1-69, IGHV3-15, and IGHV3-23.
15 . The method of claim 1 , wherein applying at least one selective pressure comprises applying a heat stress, selection with protein A, selection with protein L, or a combination thereof.
16 . The method of claim 1 , wherein the phage is a bacteriophage or a phagemid, the microbe is Escherichia coli , and the transformation is done via electroporation.
17 . The method of claim 1 , wherein the plurality of transformants comprise at least 7.6×10 10 transformants.
18 . The method of claim 1 , wherein at least 95% of the second plurality of antibodies are functional.
19 . The antibody library prepared by the method of claim 1 .
20 . The antibody library prepared by the method of claim 19 , wherein each of a plurality of antibodies in the antibody library comprises: (a) a VH domain comprising a VH-CDR1 sequence, a VH-CDR2 sequence, and a VH-CDR3 sequence; and (b) a VL domain comprising a VL-CDR1 sequence, a VL-CDR2 sequence, and a VL-CDR3 sequence; wherein (a) at least one of the VH-CDR3 sequence and the VL-CDR3 sequence is derived from a naïve B-cell; (b) the VH-CDR3 sequence or the VL-CDR3 sequence not derived from a naïve B-cell is derived from a memory B-cell; and (c) the VH-CDR1 sequence, VH-CDR2 sequence, VL-CDR1 sequence, and VL-CDR2 sequence are derived from a memory cell.