Alpha Lifetech Inc. has developed and commercialized an integrated service covering native or synthesized library construction and screening, generation of specific monoclonal antibodies, antibody humanization and antibody affinity maturation based on our phage display platform for scientists from the worldwide. With a deep understanding of peptide/protein library and antibody production, we can offer you an excellent technical support and one-stop service.

The Background of Phage Display Technology

Phage display is a laboratory technique for the study of protein–protein, protein–peptide, and protein–DNA interactions that uses bacteriophages (viruses that infect bacteria) to connect proteins with the genetic information that encodes them. This technology lies on the fact that the gene encoding the displayed molecule is packed within the same virion as a single-strained DNA (ssDNA) and the displayed peptides or proteins are expressed in fusion with phage coat protein.

The phage display technique allows the creation of libraries containing up to 10¹² different variants and could be used for affinity screening of combinatorial peptide libraries to study protein-ligand interactions and to characterize these ligands, receptor and antibody-binding sites, define epitopes for monoclonal antibodies, select enzyme substrates and screen cloned antibody repertoires. One of the most widely used library methodologies is based on the use of filamentous phage (e.g., M13), a virus that lives on E. coli and one of the most successful applications of phage display has been the isolation of monoclonal antibodies using large phage antibody libraries. For example, antibodies derived from a native antibody library of human and other species. Figure 1 shows the workflow of the phage display technology:

Fig. 1 Phage-display cycle. DNA encoding for millions of variants of certain ligands (e.g., peptides, proteins, fragments) is batch-cloned into the phage genome as part of one of the phage coat proteins (pIII, pVI or pVIII). Large libraries containing millions of different ligands can be obtained by force-cloning in E. coli. From these repertoires, phage-carrying specific-binding ligands can be isolated by a series of recursive cycles of selection on Ag, each of which involves binding, washing, elution, and amplification.

What we can do for you?

By using the phage display technology, Alpha Lifetech Inc. can offer the scientist an advanced platform to produce a high-affinity and high-specificity antibodies, including nanoantibody, diabody, chimeric antibody (such as humanized antibody), VHH single domain antibody and special monoclonal antibody (which can't be produced by hybridoma), in a very short turnaround time. We not only produce various antibodies based on M13 phage display system for clients, but also accept customers' requests to yield antibodies or proteins in T4 phage display system or T7 phage display system. And our scientists normally generate libraries with a diversity of 10⁸-10⁹, while we are also able to generate libraries over 10¹⁰ or follow our clients' specific requirements.  The main information of those three systems is shown in Table 1.  

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