UNISELECT™ Antibody Discovery and Screening
UNISELECT™ Mammalian Cell-Based Membrane Proteins Antibody Discovery & Screening! Applied StemCell provides Custom TARGATT™ Master Cell Generation in your cell lines, and ready-to-use TARGATT™ HEK293, and TARGATT™CHO to build protein libraries using site-specific transgene integration at a preselected safe harbor locus.
This is a fast, unique and efficient platform for biopanning, including bispecific mAbs, antibody discovery, antibody screening, membrane proteins, CAR-T cell screening, and for bioprocessing.
- Single copy integration
- Homogenous expression of protein variants
- Preselected safe harbor locus
- Stable protein expression
- Inducible expression compatible for membrane proteins (optional)
Brochures/ Flyers:
Poster:
TARGATT™: Rapid and Efficient Transgene Integration Technology to Develop Large Mammalian Cell-Based Screening Libraries
Webinar:
TARGATT™: A Mammalian System for Antibody/ Protein Library Screening (October 2018)
TARGATT™ System in HEK293T Cells
Figure 1. Schematic representation of site-specific gene insertion using TARGATT™ Master Cell Lines. The TARGATT™ Master Cell Line is engineered with the attP landing pad (or docking site) at a preselected safe harbor locus (hROSA26). The TARGATT™ PhiC31 integrase catalyzes an irreversible reaction between the attP sites on genome and the attB sites on the donor vector, resulting in integration of a single copy of the GFP reporter gene at the locus.
Figure 2. GFP expression in hROSA26 locus in TARGATT™ HEK293T Master Cell Lines. The CAG-GFP vector was used to verify a fast knock-in in the TARGATT™-HEK293T Master Cell Line. An enriched GFP signal was shown under fluorescence microscopy. (Left) bright field microscopy. (Right) Immunofluorescence; GFP channel.
Figure 3. TARGATT™-HEK293T Master Cell Line transfected with donor plasmid containing GFP and attB. (a) Parental HEK293T cell line only (control); (b) Parental HEK293T cell line was transfected with donor plasmid containing GFP reporter by random insertion (+GFP); (c) TARGATT™-HEK293T Master Cell Line was transfected with GFP donor plasmid before ganciclovir (GCV) selection (GFP+); (d) TARGATT™-HEK293T Master Cell Line was transfected with GFP donor plasmid after GCV negative selection to eliminate clones without gene of interest (GFP+GCV). The data indicates that the TARGATT™-HEK293 Master Cell Line system provides a robust, fast and efficient integration platform for generating a uniform cell population with stable transgene expression in the hROSA26 locus. This platform paves the way for homogeneous expression of gene of interest and subsequent protein production.
TARGATT™ System in CHO Cells
Figure 4. TARGATT™-CHO Master Cell Line with GFP transgene integration into the hH11 locus. GFP signal was detected by fluorescence imaging after transfection with donor construct by random insertion in bright field (a) and GFP channel (b), and TARGATT™ integration plus GCV selection in bright field (c) and GFP channel (d).
The TARGATT™ Knock-in Master Cell Line Kit uses PhiC31 integrase to insert any gene of interest into a preselected intergenic and transcriptionally active genomic locus (hROSA26, hH11, or other pre-defined safe harbor loci). The TARGATT™ technology can be utilized for generating knock-in cell lines and libraries for a variety of applications including reporter gene expression, gene knockdown, conditional/ inducible gene expression, gene overexpression, expression libraries for antibody discovery, antibody screening, bioproduction of recombinant protein, and disease modeling.
Comparing TARGATT™ with lentivirus-based mammalian cell libraries
Figure 1. Schematic representation of a lentiviral method of generating a mammalian cell library.
Figure 2. Schematic representation of the TARGATT™ method of generating a mammalian cell library. The process is very similar to lentiviral library but more efficient.
Applications for Cell-Based Library Screening
Antibody discovery/ antibody screening:
- Biopanning (scFv screening)
- Off-target screening with membrane protein library
- Bioprocessing
Immuno-oncology (CAR-T cells):
- CAR affinity/ efficiency screening
- CAR specificity screening for safety assessment
- “Universal” CAR-T cell
- Novel immune target discovery: biomarkers and checkpoints
Receptor identification
- Ion channels
- GPCR
Protein evolution
- Enzyme activity and specificity
- AAV capsid specificity and efficiency
Others:
- Off-target screening
- Non-membrane, non-secretary protein library
TARGATT™ Technology Applications:
- SITE-SPECIFIC INTEGRATION OF TRANSGENES (Patent Pending)
- NOVEL INTEGRATION SITES AND USES (Patent Pending)
- Venken, K. J. T., Sarrion-Perdigones, A., Vandeventer, P. J., Abel, N. S., Christiansen, A. E., & Hoffman, K. L. (2016). Genome Engineering: Drosophila melanogaster and beyond. Wiley Interdisciplinary Reviews. Developmental Biology, 5(2), 233–267.