The authors appreciate Dr. Frederic Fellouse from the Sidhu lab for critical comments on Kunkel&#39;s method based synthetic Fab phage library construction. The authors appreciate Mrs. Alevtina Pavlenco and other members from the Sidhu lab for valuable help of preparing high-efficiency electro-competent E. coli cells and high quality dU-ssDNA. This work was supported by National Natural Science Foundation of China (Grant No.: 81572698, 31771006) to DW and by ShanghaiTech University (Grant No.: F-0301-13-005) to Laboratory of Antibody Engineering.

<ol>
	<li>Singh, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monoclonal+Antibodies:+A+Review.">Monoclonal Antibodies: A Review.</a> Curr Clin Pharmacol. , (2017).</li><li>Reichert, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibodies+to+watch+in+2017.">Antibodies to watch in 2017.</a> MAbs. 9 (2), 167-181 (2017).</li><li>Kohler, G., Milstein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+cultures+of+fused+cells+secreting+antibody+of+predefined+specificity.">Continuous cultures of fused cells secreting antibody of predefined specificity.</a> Nature. 256 (5517), 495-497 (1975).</li><li>Milstein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hybridoma+revolution:+an+offshoot+of+basic+research.">The hybridoma revolution: an offshoot of basic research.</a> Bioessays. 21 (11), 966-973 (1999).</li><li>Gray, A. C., Sidhu, S. S., Chandrasekera, P. C., Hendriksen, C. F., Borrebaeck, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal-Friendly+Affinity+Reagents:+Replacing+the+Needless+in+the+Haystack.">Animal-Friendly Affinity Reagents: Replacing the Needless in the Haystack.</a> Trends Biotechnol. 34 (12), 960-969 (2016).</li><li>Hutchison, C. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutagenesis+at+a+specific+position+in+a+DNA+sequence.">Mutagenesis at a specific position in a DNA sequence.</a> J Biol Chem. 253 (18), 6551-6560 (1978).</li><li>Smith, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Filamentous+fusion+phage:+novel+expression+vectors+that+display+cloned+antigens+on+the+virion+surface.">Filamentous fusion phage: novel expression vectors that display cloned antigens on the virion surface.</a> Science. 228 (4705), 1315-1317 (1985).</li><li>Sidhu, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Phage Display in Biotechnology and Drug Discovery. , (2005).</li><li>Weiss, G. A., Watanabe, C. K., Zhong, A., Goddard, A., Sidhu, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+mapping+of+protein+functional+epitopes+by+combinatorial+alanine+scanning.">Rapid mapping of protein functional epitopes by combinatorial alanine scanning.</a> Proc Natl Acad Sci U S A. 97 (16), 8950-8954 (2000).</li><li>Frenzel, A., Schirrmann, T., Hust, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phage+display-derived+human+antibodies+in+clinical+development+and+therapy.">Phage display-derived human antibodies in clinical development and therapy.</a> MAbs. 8 (7), 1177-1194 (2016).</li><li>Sidhu, S. S., Fellouse, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+therapeutic+antibodies.">Synthetic therapeutic antibodies.</a> Nat Chem Biol. 2 (12), 682-688 (2006).</li><li>Adams, J. J., Sidhu, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+antibody+technologies.">Synthetic antibody technologies.</a> Curr Opin Struct Biol. 24, 1-9 (2014).</li><li>Kunkel, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+efficient+site-specific+mutagenesis+without+phenotypic+selection.">Rapid and efficient site-specific mutagenesis without phenotypic selection.</a> Proc Natl Acad Sci U S A. 82 (2), 488-492 (1985).</li><li>Sidhu, S. S., Lowman, H. B., Cunningham, B. C., Wells, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phage+display+for+selection+of+novel+binding+peptides.">Phage display for selection of novel binding peptides.</a> Methods Enzymol. 328, 333-363 (2000).</li><li>Persson, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CDR-H3+diversity+is+not+required+for+antigen+recognition+by+synthetic+antibodies.">CDR-H3 diversity is not required for antigen recognition by synthetic antibodies.</a> J Mol Biol. 425 (4), 803-811 (2013).</li><li>Lefranc, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IMGT+unique+numbering+for+immunoglobulin+and+T+cell+receptor+variable+domains+and+Ig+superfamily+V-like+domains.">IMGT unique numbering for immunoglobulin and T cell receptor variable domains and Ig superfamily V-like domains.</a> Dev Comp Immunol. 27 (1), 55-77 (2003).</li><li>Graille, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complex+between+Peptostreptococcus+magnus+protein+L+and+a+human+antibody+reveals+structural+convergence+in+the+interaction+modes+of+Fab+binding+proteins.">Complex between Peptostreptococcus magnus protein L and a human antibody reveals structural convergence in the interaction modes of Fab binding proteins.</a> Structure. 9 (8), 679-687 (2001).</li><li>Graille, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystal+structure+of+a+Staphylococcus+aureus+protein+A+domain+complexed+with+the+Fab+fragment+of+a+human+IgM+antibody:+structural+basis+for+recognition+of+B-cell+receptors+and+superantigen+activity.">Crystal structure of a Staphylococcus aureus protein A domain complexed with the Fab fragment of a human IgM antibody: structural basis for recognition of B-cell receptors and superantigen activity.</a> Proc Natl Acad Sci U S A. 97 (10), 5399-5404 (2000).</li><li>Huang, R., Fang, P., Kay, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvements+to+the+Kunkel+mutagenesis+protocol+for+constructing+primary+and+secondary+phage-display+libraries.">Improvements to the Kunkel mutagenesis protocol for constructing primary and secondary phage-display libraries.</a> Methods. 58 (1), 10-17 (2012).</li><li>Chen, G., Sidhu, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+generation+of+synthetic+antibody+libraries+for+phage+display.">Design and generation of synthetic antibody libraries for phage display.</a> Methods Mol Biol. 1131, 113-131 (2014).</li><li>Padlan, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+of+the+antibody+molecule.">Anatomy of the antibody molecule.</a> Mol Immunol. 31 (3), 169-217 (1994).</li><li>Virnekas, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trinucleotide+phosphoramidites:+ideal+reagents+for+the+synthesis+of+mixed+oligonucleotides+for+random+mutagenesis.">Trinucleotide phosphoramidites: ideal reagents for the synthesis of mixed oligonucleotides for random mutagenesis.</a> Nucleic Acids Res. 22 (25), 5600-5607 (1994).</li><li>Fellouse, F. A., Sidhu, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Making and Using Antibodies: A Practical Handbook. , 157-180 (2006).</li><li>Fantini, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+antibody+library+diversity+through+next+generation+sequencing+and+technical+error+compensation.">Assessment of antibody library diversity through next generation sequencing and technical error compensation.</a> PLoS One. 12 (5), e0177574 (2017).</li><li>Glanville, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deep+sequencing+in+library+selection+projects:+what+insight+does+it+bring?.">Deep sequencing in library selection projects: what insight does it bring?.</a> Curr Opin Struct Biol. 33, 146-160 (2015).</li><li>Perelson, A. S., Oster, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theoretical+studies+of+clonal+selection:+minimal+antibody+repertoire+size+and+reliability+of+self-non-self+discrimination.">Theoretical studies of clonal selection: minimal antibody repertoire size and reliability of self-non-self discrimination.</a> J Theor Biol. 81 (4), 645-670 (1979).</li><li>Miersch, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scalable+high+throughput+selection+from+phage-displayed+synthetic+antibody+libraries.">Scalable high throughput selection from phage-displayed synthetic antibody libraries.</a> J Vis Exp. (95), e51492 (2015).</li><li>Ponsel, D., Neugebauer, J., Ladetzki-Baehs, K., Tissot, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+affinity,+developability+and+functional+size:+the+holy+grail+of+combinatorial+antibody+library+generation.">High affinity, developability and functional size: the holy grail of combinatorial antibody library generation.</a> Molecules. 16 (5), 3675-3700 (2011).</li><li>Petering, J., McManamny, P., Honeyman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibody+therapeutics+-+the+evolving+patent+landscape.">Antibody therapeutics - the evolving patent landscape.</a> N Biotechnol. 28 (5), 538-544 (2011).</li></ol>

The authors have nothing to disclose.

To construct high diversity, phage-displayed Fab libraries, quality control check points are needed to monitor various stages of the construction process, including the competency of electro-competent cells, quality of the dU-ssDNA template, efficiency of CCC-dsDNA synthesis, titer after electroporation, Fab folding, and amino acid diversity of CDRs by sequence analysis of Fab-phage clones.
High yield and purity of dU-ssDNA is essential for high mutagenesis rate. In our experience, phage induc...

mAbs have broad applications ranging from basic research to disease diagnostics and therapeutics. As of 2016, more than 60 mAbs have been approved by the United States Food and Drug Administration (USFDA) for clinical treatment of autoimmune diseases, cancer, and infectious diseases1,2.
In 1975, Kohler and Milstein reported a technique for the continuous generation of antibodies of a single clonal specificity from a cellular source referred to as &#39;hybridomas&#39; and this technique has subsequently become a cornerstone in medicine and industry3,4. Generation of mAbs by this method requires various steps including antigen production, mouse immunization, extraction of B lymphocytes, fusion of B cells with myeloma cells to form immortal hybridoma cells, clone selection, and for therapeutic applications, humanization is required to avoid human anti-mouse antibody (HAMA)4,5. However, for this technology, antigens including toxins, pathogens, and highly conserved proteins are relatively ineffective in triggering an in vivo immune response for mAb production5.
In 1978, Hutchison et al. reported the use of an oligonucleotide to direct mutagenesis of a residue in a single-stranded bacteriophage virus6. In 1985, Smith reported that foreign gene fragments can be fused in frame with the gene encoding phage coat protein III and can thus be displayed on the phage surface without compromising its infectivity7. These pioneering works laid a foundation for the subsequent construction of phage-displayed antibody libraries in immune, na&#239;ve, and synthetic forms with the formats of single-chain variable fragment (scFv) and antigen-binding fragment (Fab) for therapeutic mAb development8,9. From the technical point of view, phage display-based antibody development offers a complementary approach to hybridoma-based mAb development that can help to circumvent the limitations some antigens can pose and the humanization process that hybridoma-derived antibodies often require5. As of 2016, 6 phage display-derived mAbs have been approved in the market including Humira, one of the most successful mAbs used for treatment of rheumatoid arthritis, and many phage display-derived antibody candidates are currently at various stages of clinical investigation10.
For immune and na&#239;ve phage antibody libraries, the diversity of complementarity-determining regions (CDRs) in light and heavy chain is derived from the natural immune repertoire (i.e., from B cells). In contrast, the diversity of CDRs in synthetic phage antibody libraries is entirely artificial. Synthetic approaches to library construction provide precise control over the design of sequence diversity and offer opportunities for mechanistic studies of antibody structure and function11,12. Moreover, the framework for synthetic libraries can be optimized before library construction to facilitate downstream, large-scale industrial development11,12.
In 1985, Kunkel reported a single-stranded DNA (ssDNA) template-based mutagenesis approach to introduce site-directed mutations into M13 bacteriophage efficiently13. This approach was subsequently used widely for construction of phage-displayed libraries. Chemically synthesized DNA oligonucleotides designed to introduce diversity into Fab CDRs are incorporated into a phagemid with an antibody backbone template. In this process, the phagemid is expressed as a uracil-containing ssDNA (dU-ssDNA) and the oligonucleotides are annealed onto the CDRs and extended to synthesize double-stranded DNA (dsDNA) in the presence of T7 DNA polymerase and T4 DNA ligase. Finally, generated ds-DNA can be introduced into Escherichia coli by electroporation.
For high diversity, phage-displayed library construction, high-voltage electroporation of a two-component mixture of electro-competent cells and covalently closed circular dsDNA (CCC-dsDNA) should be prepared carefully. Sidhu et al. modified the preparation of electro-competent cells and DNA from traditional methods and greatly improved library diversity14.
In this protocol, we describe a method for construction of synthetic phage-displayed Fab libraries with diversities of 109-1010 obtainable with a single electroporation. Figure 1 shows an overview of library construction including: 1) high-efficiency electro-competent cell preparation; 2) extraction of dU-ssDNA; 3) Kunkel&#39;s method based oligonucleotide-directed mutagenesis; 4) electroporation and calculation of library size; 5) protein A/L-based ELISA for folding and functional diversity evaluation; and 6) DNA sequence analysis of diversity. All the reagents, strains and equipment are listed in the Material&#39;s Table. Table 1 shows the reagent setup.

<table>
	<tbody>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1.0 M H3PO4</td>
			<td>Fisher</td>
			<td>AC29570</td>
			<td></td>
		</tr>
		<tr>
			<td>1.0 M Tris, pH 8.0</td>
			<td>Invitrogen</td>
			<td>15568-025</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mM ATP</td>
			<td>Invitrogen</td>
			<td>18330-019</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mM dithiothreitol</td>
			<td>Fisher</td>
			<td>BP172</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mM dNTP mix</td>
			<td>GE Healthcare</td>
			<td>28-4065-60</td>
			<td>solution containing 25 mM each of dATP, dCTP, dGTP and dTTP.</td>
		</tr>
		<tr>
			<td>3,3&#8217;,5,5&#8217;-tetramethylbenzidine (TMB)</td>
			<td>Kirkegaard &#38; Perry Laboratories Inc</td>
			<td>50-76-02</td>
			<td></td>
		</tr>
		<tr>
			<td>50X TAE</td>
			<td>Invitrogen</td>
			<td>24710030</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Fisher</td>
			<td>BP160</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbenicillin, carb</td>
			<td>Sigma</td>
			<td>C1389</td>
			<td>100 mg/mL in water,&#160; 0.22 &#956;m filter-sterilize, work concentration: 100 &#956;g/mL.</td>
		</tr>
		<tr>
			<td>Chloramphenicol, cmp</td>
			<td>Sigma</td>
			<td>C0378</td>
			<td>100 mg/mL in ethanol, 0.22 &#956;m filter-sterilize, work concentration: 10 &#956;g/mL.</td>
		</tr>
		<tr>
			<td>EDTA 0.5 M, pH 8.0</td>
			<td>Invitrogen</td>
			<td>AM9620G</td>
			<td></td>
		</tr>
		<tr>
			<td>Granulated agar</td>
			<td>VWR</td>
			<td>J637-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>H2O2 peroxidase substrate</td>
			<td>Kirkegaard &#38; Perry Laboratories Inc</td>
			<td>50-65-02</td>
			<td></td>
		</tr>
		<tr>
			<td>K2HPO4</td>
			<td>Sigma</td>
			<td>795488</td>
			<td></td>
		</tr>
		<tr>
			<td>Kanamycin, kan</td>
			<td>Fisher</td>
			<td>AC61129</td>
			<td>50 mg/mL in water,&#160; 0.22 &#956;m filter-sterilize, work concentration: 50 &#956;g/mL.</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>P2222</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Sigma</td>
			<td>94046</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Alfa Aesar</td>
			<td>U19C015</td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop</td>
			<td>Fisher</td>
			<td>ND2000C</td>
			<td></td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>Fisher</td>
			<td>SS256</td>
			<td>! CAUTION NaOH causes burns.</td>
		</tr>
		<tr>
			<td>NON-Fat Powdered Milk</td>
			<td>Sangon Biotech</td>
			<td>A600669</td>
			<td></td>
		</tr>
		<tr>
			<td>PEG-8000</td>
			<td>Fisher</td>
			<td>BP233</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein A-HRP conjugate</td>
			<td>Invitrogen</td>
			<td>101123</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAprep Spin M13 Kit</td>
			<td>Qiagen</td>
			<td>22704</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAquick Gel Extraction Kit</td>
			<td>Qiagen</td>
			<td>28706</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAquick PCR Purification Kit</td>
			<td>Qiagen</td>
			<td>28104</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Protein L</td>
			<td>Fisher</td>
			<td>77679</td>
			<td></td>
		</tr>
		<tr>
			<td>T4 DNA polymerase</td>
			<td>New England Biolabs</td>
			<td>M0203S</td>
			<td></td>
		</tr>
		<tr>
			<td>T4 polynucleotide kinase</td>
			<td>New England Biolabs</td>
			<td>M0201S</td>
			<td></td>
		</tr>
		<tr>
			<td>T7 DNA polymerase</td>
			<td>New England Biolabs</td>
			<td>M0274S</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetracycline, tet</td>
			<td>Sigma</td>
			<td>T7660</td>
			<td>50 mg/mL in water, 0. 22 &#956;m filter-sterilize, work concentration: 10 &#956;g/mL.</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Fisher</td>
			<td>0123-07-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween-20</td>
			<td>Sigma</td>
			<td>P2287</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrapure glycerol</td>
			<td>Invitrogen</td>
			<td>15514-011</td>
			<td></td>
		</tr>
		<tr>
			<td>Uridine</td>
			<td>Sigma</td>
			<td>U3750</td>
			<td>25 mg/mL in ethanol, work concentration: 0.25 &#956;g/mL.</td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>VWR</td>
			<td>DF0127-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company </td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Strains</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>E.coli CJ236</td>
			<td>New England Biolabs</td>
			<td>E4141</td>
			<td>Genotype: dut-&#160; ung-&#160; thi-1 relA1 spoT1 mcrA/pCJ105(F&#39; camr). Used for preparation of dU-ssDNA.</td>
		</tr>
		<tr>
			<td>E.coli SS320</td>
			<td>Lucigen</td>
			<td>60512</td>
			<td>Genotype: [F&#39;proAB+lacIq lacZ&#916;M15 Tn10 (tetr)] hsdR mcrB araD139 &#916;(araABC-leu)7679 &#916;lacX74 galUgalK rpsL thi. Optimized for high-efficiency electroporation and filamentous bacteriophage production.</td>
		</tr>
		<tr>
			<td>M13KO7</td>
			<td>New England Biolabs</td>
			<td>N0315S</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company </td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>0.2-cm gap electroporation cuvette</td>
			<td>BTX</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>96-well 2mL Deep-well plates</td>
			<td>Fisher</td>
			<td>278743</td>
			<td></td>
		</tr>
		<tr>
			<td>96-well Maxisorp immunoplates</td>
			<td>Nunc</td>
			<td>151759</td>
			<td></td>
		</tr>
		<tr>
			<td>Baffled flasks</td>
			<td>Corning</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Benchtop centrifuge</td>
			<td>Eppendorf</td>
			<td>5811000096</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge bottles</td>
			<td>Nalgene</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ECM-630 electroporator</td>
			<td>BTX</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic stir bars</td>
			<td>Nalgene</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thermo Fisher centrifuge</td>
			<td>Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High speed shaker</td>
			<td>TAITEK</td>
			<td>MBR-034P</td>
			<td></td>
		</tr>
		<tr>
			<td>Microplate shaker</td>
			<td>QILINBEIER</td>
			<td>QB-9002</td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid handler for 96 and 384 wells</td>
			<td>RAININ</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mutil-channel pipette</td>
			<td>RAININ</td>
			<td>E4XLS</td>
			<td></td>
		</tr>
		<tr>
			<td>Amicon concentrator</td>
			<td>Merck</td>
			<td>UFC803096</td>
			<td></td>
		</tr>
	</tbody>
</table>

construction of synthetic phage displayed fab library with tailored diversity

Demand for monoclonal antibodies (mAbs) in basic research and medicine is increasing yearly. Hybridoma technology has been the dominant method for mAb development since its first report in 1975. As an alternative technology, phage display methods for mAb development are increasingly attractive since Humira, the first phage-derived antibody and one of the best-selling mAbs, was approved for clinical treatment of rheumatoid arthritis in 2002. As a non-animal based mAb development technology, phage display bypasses antigen immunogenicity, humanization, and animal maintenance that are required from traditional hybridoma technology based antibody development. In this protocol, we describe a method for construction of synthetic phage-displayed Fab libraries with diversities of 109-1010 obtainable with a single electroporation. This protocol consists of: 1) high-efficiency electro-competent cell preparation; 2) extraction of uracil-containing single-stranded DNA (dU-ssDNA); 3) Kunkel&#39;s method based oligonucleotide-directed mutagenesis; 4) electroporation and calculation of library size; 5) protein A/L-based enzyme-linked immunosorbent assay (ELISA) for folding and functional diversity evaluation; and 6) DNA sequence analysis of diversity.

Following the flow chart of the Fab library construction (see Figure 1), we prepared M13KO7 helper phage pre-infected E. coli SS320 electro-competent cells. The efficiency of these electro-competent cells is estimated as 2 X 109 cfu/&#181;g when the Fab phagemid backbone for library construction was used (Figure 4).
The uracil incorporation efficienc...

Watch this Scientific Journal Video about Construction of Synthetic Phage Displayed Fab Library with Tailored Diversity at JoVE.com

Construction of Synthetic Phage Displayed Fab Library with Tailored Diversity

This protocol describes a detailed procedure for the construction of a phage-displayed synthetic antibody library with tailored diversity. Synthetic antibodies have broad applications from basic research to disease diagnostics and therapeutics.

Demand for monoclonal antibodies (mAbs) in basic research and medicine is increasing yearly. Hybridoma technology has been the dominant method for mAb ...

The overall goal of this procedure is to provide readers detailed hands-on experience in constructing a phage displayed synthetic human antibody library with tailored diversity. Synthetic phage displayed antibody libraries have great potential for replace traditionally hybridoma-based techniques for therapeutic monoclonal antibody development by bypassing the need for animal immunization and the subsequent antibody humanization. The advantage of synthetic antibody library is that tailored diversity is introduced into an antibody framework using insight into positional diversity that support high affinity interaction and desirable protein properties.Beyond the practical utility, synthetic antibody libraries can also be used to experimentally probe the role of specific amino acids in biomolecular interactions, thus supporting their own continuous improvement. This procedure will be demonstrated by graduate student named Zhenwei Zhong and Doctor Shin-chen Hou from our laboratory. To be

construction-synthetic-phage-displayed-fab-library-with-tailored

Research

JoVE Journal

Immunology and Infection

13.4K Views.  ShanghaiTech University. The overall goal of this procedure is to provide readers detailed hands-on experience in constructing a phage displayed synthetic human antibody library with tailored diversity. Synthetic phage displayed antibody libraries have great potential for replace traditionally hybridoma-based techniques for therapeutic monoclonal antibody development by bypassing the need for animal immunization and the subsequent antibody humanization. The advantage of synthetic antibody library is that tailored div...