ADC Development Solutions

ADCs Target Protein and Customization Services

In the early stages of ADC drug development, the antibody must specifically bind to antigens on tumor cells to target them accurately. As a result, preparing highly pure and active target antigen proteins is essential for successful ADC development. These proteins are used to screen and validate antibody specificity, assess ADC drug cytotoxicity in vitro, and perform cell function tests.

CUSABIO has years of experience in protein expression and offers a range of target antigens from different species and with various tags. These proteins are suitable for experiments like immunization, antibody screening, SPR, and cell activity assays.

Here are the key features of these proteins.

● Multi-species Proteins for Cross-validation

B-lymphocyte antigen CD20 (MS4A1)

Species: Human

Code: CSB-MP015007HU

Species: Dog

Code: CSB-MP661636DO

Species: Macaca fascicularis

Code: CSB-MP4516MOV

● High Purity

Recombinant Human Folate receptor alpha(FOLR1),partial (Active)

Code: CSB-MP4516MOV

The purity of FOLR1 was greater than 95% as determined by SEC-HPLC.

● ELISA/LSPR/BIL for Bioactivity Verification

Recombinant Human Claudin-18.2 (CLDN18.2)

CSB-MP005498HU(A5)l5

Measured by its binding ability in a functional ELISA. Immobilized Human CLDN18.2 at 10 μg/ml can bind Anti-CLDN18.2 recombinant antibody (CSB-RA005498A1HU), the EC₅₀ is 5.115-8.534 ng/mL. The VLPs (CSB-MP3838) are negative control.

Recombinant Human Leukocyte surface antigen CD47 (CD47)

CSB-MP004940HU

Human SIRPA protein His/Myc tag (CSB-MP021334HU) captured on COOH chip can bind Human CD47 protein Fc tag (CSB-MP004940HU) with an affinity constant of 19.1 nM as detected by LSPR Assay.

Recombinant Human Cystine/glutamate transporter (SLC7A11)

CSB-CF892171HU(A4)

Loaded Anti-Human SLC7A11 Antibody (CSB-RA892171MA1HU) on 96-Flat plate, can bind Human SLC7A11, with an affinity constant of ＜1 pM as determined in BLI assay (Gator Prime).

● High Batch-to-Batch Consistency

Lot.No.	EC50(ng/mL)
DD05827k1g0wl	1.216-1.438
DD05868k1g0wl	1.353-1.587
DD05886k1g0wj	1.352-1.600

The binding activity of three different lots of Human AXL, his Tag (CSB-MP326981HUd7) and Anti-AXL recombinant antibody (CSB-RA326981MA1HU) was evaluated by ELISA.

The result shows very high batch-to-batch consistency.

● ADCs Target Protein Products

● ADCs Target Protein Customization Service

Therapeutic Antibody Discovery Service

Antibody discovery is the first and critical step in drug development, directly impacting efficacy and safety. For 17 years, CUSABIO has focused on protein and antibody R&D, screening over 100 therapeutic antibody candidates for pharmaceutical companies—many now in the CMC or IND stages. With expertise in antigen preparation and antibody screening, we provide a one-stop solution from target identification to therapeutic antibody candidates, helping accelerate drug development.

CUSABIO offers two antibody discovery platforms: hybridoma and single B cell technology.

● Hybridoma Antibody Discovery

CUSABIO has 16 years of experience in hybridoma monoclonal antibody development. Their technical processes are mature, ensuring stable and reliable product quality. The initial positive rate reaches 20%-40%, while the FACS positive rate is 10%-20%. These rates meet the diverse needs of various customers.

CUSABIO performs functional tests on therapeutic antibodies after screening. These tests include antigen ELISA, cell FACS, antigen SPR, and antigen-binding assays. The tests are tailored to your needs. They ensure the antibodies work well in FACS experiments with stable cell lines.

- Case Display

Immunization

ELISA preliminary screening after electrofusion

FACS screening of supernatants after subcloning

18 positive clones from different plates were determined after comparison with the reference antibody.

Recombinant expression after sequencing positive clones

According to the FACS ranking, the top 7 unique sequences were expressed and validated with the A549 cell.

● Single B Cell Antibody Discovery

Single B cell antibody technology has several advantages over traditional methods like hybridoma and phage display. It has shorter development cycles, higher throughput, more positive clones, and higher affinity, ensuring the natural pairing of light and heavy chains.

CUSABIO provides a one-stop service for single B cell antibody preparation. The service is fast, high-throughput, and delivers antibodies with high specificity and affinity. Our comprehensive process includes immunogen design, antibody production, and detection method development, ensuring clients receive high-quality antibody solutions.

- Case Display

Cell sorting

High positivity rate

Linear expression vector construction

FACS validation

Antibody Molecular Optimization

The mammalian cell display platform is designed to optimize therapeutic antibodies' developability. Mammalian cells grown in dishes closely resemble human clinical conditions and industrial antibody production. This platform is a cutting-edge tool for antibody engineering, including affinity maturation and humanization.

● CUSABIO Presents:

Human-like PTM

Fine-tuned biophysical property

Better developability

Best for antibody engineering

- Application 1: Affinity

The affinity of the customer's mAb was enhanced 100-fold by mutating one AA in CDR3.

The affinity of the customer's mAb against cynomolgus antigen was enhanced 100-fold by mutating one AA in each CDR3 while retaining the affinity to human antigen.

Customers' in vivo data further proves the good quality of the engineered variants.

More affinity maturation

TCR affinity maturation

Blocking activity of small molecules (chemical compound)

- Application 2: Humanization

The customer's mAb was humanized through a library specifically designed for screening high-affinity molecules, and the affinity of humanized antibodies could be 10-fold higher than the parent molecule.

WT and the engineered molecules were also compared through ELISA and flow cytometry.

Positive Control Antibody

CUSABIO supports drug development by developing recombinant antibodies for drug discovery. These recombinant antibodies are expressed in mammalian cells and tested in protein activity assays. They can serve as positive controls in drug discovery or validate the activity of corresponding proteins.

FC Validation of Antibody Specificity

DLL3 Recombinant Monoclonal Antibody

CSB-RA882142A1HU

CLDN18 Recombinant Monoclonal Antibody

CSB-RA005498A2HU

Functional ELISA for Validating Antibody Activity

GCGR Recombinant Monoclonal Antibody

CSB-RA009316A1HU

Claudin-18.2 Recombinant Monoclonal Antibody

CSB-RA005498A1HU

DT3C Recombinant Protein

DT3C is a recombinant protein mainly used for in vitro evaluation of the internalization efficiency of cancer cells towards monoclonal antibodies (mAbs), thereby enabling the screening of more effective monoclonal antibodies. This protein contains a diphtheria toxin (DT) protein lacking a receptor binding domain and Streptococcus protein G.

Compared to commonly used antibody internalization efficiency detection techniques such as acid buffer elution, Mab-ZAP, pHrodo, etc., the DT3C recombinant protein assay is characterized by its simplicity, speed, and high detection efficiency.

In vitro detection of ADC antibody internalization efficiency

Antibody internalization efficiency is higher than Mab-ZAP

In vitro detection of ADC antibody internalization efficiency

Reference: M. Yamaguchi et al. Biochemical and Biophysical Research Communications 454 (2014) 600-603.

DT3C and CCR8 antibodies prepared by CUSABIO are incubated and then applied to different cell lines

After DT3C 10μg/ml formed complexes with different concentrations of Anti-CCR8 antibodies (CSB-RA004847MA3HU), cytotoxicity experiments were conducted on CHOK1/Human CCR8 cells (CSB-SC004847HU2). The ED₅₀ is 0.3708-0.5608 μg/ml.

After DT3C 10μg/ml formed complexes with different concentrations of Anti-CCR8 antibodies (CSB-RA004847MA3HU), cytotoxicity experiments were conducted on CT26/Human CCR8 cells (CSB-SC004847HU3). The ED₅₀ is 0.4661-0.8614 μg/ml.

Overexpression Cell Line and Construction Service

Overexpression stable cell lines are specially engineered cells generated from a specific cellular lineage that can stably overexpress or suppress a particular gene. Unlike transient transfection, which only allows transient gene expression, these cell lines can continue to express specific genes.

● Applications

● Service Advantages

● Case Display

HEK293T/Human CLDN6 Stable Cell Line (CSB-SC005508HU)

CT26/Human ROR1 Stable Cell Line (CSB-SC020067HU)

HEK293F/Human DLL3 Stable Cell Line (CSB-SC882142HU)

Reporter Gene Cell Line and Construction Service

Reporter gene cell line construction uses molecular cloning techniques. This process inserts a reporter gene (e.g., luciferase) into cellular DNA. Subsequent selection and cultivation establish stable cell lines with continuous reporter gene expression.

● Applications

CUSABIO provides reporter gene cell line construction services and spot products.

● Case Display

NF-κB (Luc) HEK293 Reporter Cell Code: CSB-SC6123HU

Anti-payload Antibodies and Customized Service

Payload is a key component of ADC drugs. It targets tumor cell molecules to disrupt their functions and prevent growth and division, thus killing cancer cells. During ADC quality control, anti-payload antibodies are used to detect the ADC's payload, evaluating drug stability, safety, and efficacy.

CUSABIO provides research tools for preclinical and clinical studies of anti-payload antibodies (e.g., Anti-DXD mAb, Anti-MMAE/MMAF, Anti-Eribulin, etc.). These tools enable pharmacokinetic monitoring and drug-antibody ratio (DAR) analysis in blood samples.

● Types of Anti-payload Antibodies

● Case Display

High Purity

The Mouse Anti-DXD Antibody (Code: CSB-MA996977I2m) has a purity of more than 90% as determined by SEC-HPLC and SDS-PAGE.

High Purity

The Mouse Anti-Eribulin Antibody (Code: CSB-MA943989I1m) has a purity of more than 98% as determined by SEC-HPLC and SDS-PAGE.

High-Affinity Functional ELISA Validation

Anti-DXD mAb

CSB-MA996977I1m

Anti-SN38 mAb

CSB-MA187707I1m

High Affinity for Clinical ADC Drugs

Anti-DXD mAb

CSB-MA996977I2m

Higher Activity Compared to Other Manufacturers' Antibodies

Activity: Measured by its binding ability in a functional ELISA. Immobilized T-DXd (DS-8201) at 2 μg/mL can bind Anti-DXD antibody, the activity was 4-5 times that of other companies.

Anti-idiotype Antibody Customization Service

Anti-idiotype antibodies share structural similarities with anti-drug antibodies (ADAs), which enables their use as positive controls for ADA quantification in immunogenicity assessments. In pharmacokinetic (PK) and pharmacodynamic (PD) studies, these antibodies are used to measure blood levels of antibody drugs in free, bound, and total forms.

CUSABIO provides anti-idiotypic rabbit polyclonal antibody preparation and anti-idiotypic mouse mAb preparation (anti-Fab and anti-ScFv). Leveraging five core protein expression and kit development platforms, CUSABIO delivers end-to-end solutions encompassing antigen production, anti-idiotype antibody development, analytical assay establishment, and kit development.

● Comparison of Different Methods in Pharmacokinetic (PK) Analysis

Type	Antigen Capture	Anti-idiotype Antibody Capture	Sandwich ELISA
Schematic Diagram
Advantages	Anti-idiotypic antibodies are not required	Only one anti-idiotypic antibody is needed, a relatively simple development process	High sensitivity; high accuracy
Disadvantages	Lower sensitivity; lower accuracy	Easy to have cross-reactions with other subtypes	Relatively difficult development process

● Comparison of Different Methods in Immunogenicity Analysis

Type	Antigen Capture	Anti-idiotype Antibody Capture
Schematic Diagram
Advantages	Anti-idiotypic antibodies are not required	High accuracy
Disadvantages	Lower sensitivity; lower accuracy	Relatively difficult development process, limited detection range

Cytokine ELISA Kits & Kit Customization Service

Cytokine detection is critical for ADC drug development, particularly in the immunogenicity assessment, pharmacodynamics studies, and safety evaluations.

CUSABIO has developed the IS series of cytokine detection assay kits for industrial clients, including pharmaceutical companies. These kits are produced with high-performance raw materials, meet strict production standards, and undergo multiple quality controls. Developed through advanced R&D platforms, these kits are suitable for key applications: cytokine release syndrome (CRS) detection, residual process material testing in drug manufacturing, pharmacokinetic experimental cell function evaluation, quality control in developing cell therapy drugs, and pharmacological efficacy testing.

● IS series VS RUO series

Human Interleukin 10,IL-10 ELISA KIT as an example:

IS series industrial special products--CSB-E04593h-IS

Sample Types: serum, plasma, tissue homogenates, cell culture supernates

Detection Range: 3.9 pg/ml-250 pg/ml

Sensitivity: 0.975 pg/ml

Standard Curve:

Precision:

	Intra-Assay Precision			Inter-Assay Precision
Sample	1	2	3	1	2	3
n	20	20	20	20	20	20
Mean (pg/ml)	35.83	33.975	36.452	33.565	36.973	36.037
SD	0.031	0.024	0.029	0.041	0.034	0.036
CV(%)	5.688	4.554	5.263	7.839	6.115	6.581

Conventional scientific research products--CSB-E04593h

Sample Types: serum,plasma, tissue homogenates

Detection Range: 31.25 pg/ml- 2000 pg/ml

Sensitivity: 7.8 pg/ml

Standard Curve:

Precision:

	Intra-Assay Precision			Inter-Assay Precision
Sample	1	2	3	1	2	3
n	20	20	20	20	20	20
Mean (pg/ml)	251.241	254.176	249.776	246.854	255.646	251.974
SD	0.028	0.024	0.027	0.04	0.037	0.035
CV(%)	5.283	4.494	5.114	7.634	6.903	6.591

● Product List of IS Series Cytokine ELISA Kits

Currently, CUSABIO provides 287 types of high-quality cell cytokine detection ELISA kits and offers custom antibody pairs and ELISA kit services based on your needs.

Have questions? Our experts are ready to help.