Anti-Omalizumab Antibodies

Antibodies for bioanalytical assays to measure omalizumab and biosimilar products

Ready-made recombinant monoclonal anti-idiotypic antibodies, highly specific for the humanized monoclonal antibody drug omalizumab (Xolair).

Type 1 anti-idiotypic antibody

Anti-Omalizumab Inhibitory Antibodies

These inhibitory (Type 1) antibodies specifically recognize the free humanized monoclonal antibody omalizumab. They do not recognize free human IgE (hIgE) or omalizumab in complex with hIgE. They are ideal as capture and detection reagents in a pharmacokinetic (PK) bridging ELISA to measure free drug, and as a surrogate positive control for an anti-drug antibody (ADA) assay.

Catalog Numbers: HCA235, HCA235P, HCA236

Type 3 anti-drug-target complex specific antibody

Anti-Omalizumab-hIgE Complex Specific Antibodies

These drug-target complex specific (Type 3) antibodies recognize the complex of omalizumab and hIgE. They do not bind to free omalizumab or hIgE alone. With these antibodies, an antigen capture PK assay can be developed that avoids the bridging format, enabling measurement of free drug.

Catalog Numbers: HCA237, HCA237P, HCA238

 

Our recombinant monoclonal antibodies are generated using Human Combinatorial Antibody Library (HuCAL®) technology and CysDisplay®, a proprietary method of phage display, and employing guided selection methods to obtain highly targeted reagents. The result is highly specific and high affinity antibodies, ideal for development of PK assays. HuCAL antibodies are fully human, and when in full length IgG format they can be used as a control or calibrator in an ADA assay. The in vitro production of recombinant antibodies results in a consistent, secure supply of these critical reagents throughout preclinical development and clinical trials.

More information about anti-idiotypic antibodies and their binding types and properties

Anti-biotherapeutic antibody quality control and characterization


Table 1. Antibodies Specific to Omalizumab

Catalog # Clone Antibody Specificity Binding Type Format Affinity KD, nM Assay Development Recommendations
HCA236 AbD20669 Omalizumab Inhibitory Fab-FH1 1.1 PK bridging ELISA
capture antibody
HCA235 AbD20669_hIgG1 Omalizumab Inhibitory Human IgG1 1.12 PK bridging ELISA
detection antibody 
ADA bridging ELISA
HCA235P AbD20669_hIgG1 Omalizumab Inhibitory Human IgG1
HRP labeled
1.12 PK bridging ELISA
detection antibody
HCA238 AbD20760 Omalizumab/hIgE Complex-specific Fab-FH1 0.58 
(on complex)
PK ELISA antigen
capture format
HCA237 AbD20760_hIgG1 Omalizumab/hIgE Complex-specific Human IgG1 0.58
(on complex)
PK ELISA antigen
capture format
HCA237P AbD20760_hIgG1 Omalizumab/hIgE Complex-specific human IgG1
HRP labeled
0.58
(on complex)
PK ELISA antigen
capture format

1 F=DYKDDDDK-tag; H=His-6-tag
2 Affinity measured in the monovalent Fab form

Related Products

Omalizumab drug target Recombinant human IgE lambda (HCA171)
Omalizumab drug isotype control Recombinant human IgG1 kappa (HCA192)
Omalizumab biosimilar for research use Human Anti-IgE Antibody (MCA6105)


Pharmacokinetic Assay – Bridging ELISA Format

Schematic image of PK Bridging ELISA. Anti-idiotypic capture antibody, Fab format (purple), monoclonal antibody drug (gold), anti-idiotypic detection antibody, Ig format (blue), labeled with HRP

Fig. 1. Omalizumab PK ELISA bridging format using antibodies HCA235 and HCA236.

Measurement of free drug with human anti-omalizumab antibodies

In figure 1, Anti-Omalizumab Antibody, clone AbD20669 (HCA236) was coated at 1.0 µg/ml on a microtiter plate and left overnight. After washing and blocking with PBST + 5% BSA, 10% human serum was added spiked with increasing concentrations of omalizumab. Detection was performed by adding HRP conjugated Anti-Omalizumab Antibody, clone AbD20669_hIgG1 (HCA235P) at a concentration of 2 µg/ml in HISPEC Assay Diluent (BUF049A) and QuantaBlu Fluorogenic Peroxidase Substrate. Data are shown as the mean of three measurements.

Protocol: Omalizumab PK bridging ELISA using HCA236 and HCA235P


Pharmacokinetic Assay – Antigen Capture Format

Schematic image of PK antigen capture format ELISA. Drug target (red), monoclonal antibody drug (gold), drug-target complex detection antibody, Ig format (blue) labeled with HRP

Fig. 2. Omalizumab PK Antigen Capture ELISA using antibody HCA237P.


In figure 2, a microtiter plate was coated overnight with Human IgE (HCA171) at a concentration of 5 µg/ml. After washing and blocking with PBST + 5% BSA, 10% human serum was added spiked with increasing concentrations of omalizumab. Detection was performed using HRP conjugated Human Anti-Omalizumab/IgE Antibody, clone AbD20760_hIgG1 (HCA237P) at a concentration of 2 µg/ml in HISPEC Assay Diluent (BUF049A) followed by QuantaBlu Fluorogenic Peroxidase Substrate. Data are shown as the mean of three measurements.

Protocol: Omalizumab PK antigen capture ELISA using HCA237P or HCA238


Inhibition ELISA

Fig. 3. Demonstration of the inhibitory property of antibody HCA236

In figure 3,  a microtiter plate was coated overnight with Human IgE (HCA171) at a concentration of 1 µg/ml. After washing and blocking with PBST + 5% BSA, a pre-incubated mixture of omalizumab (0.3 µg/ml) plus increasing concentrations of Human Anti-Omalizumab Antibody, clone AbD20669 (HCA236) was added. Free omalizumab, still capable of binding to the human IgE-coated plate, was detected using an HRP conjugated goat anti-human IgG (Fc specific) antibody and QuantaBlu Fluorogenic Peroxidase Substrate. Data are shown as the mean of three measurements. 


Anti-Drug Antibody Assay - Bridging ELISA

Schematic image of ADA bridging assay. Monoclonal antibody drug as capture antibody and detection antibody labeled with HRP (gold), fully human anti-idiotypic antibody, Ig format (blue)

Fig. 4. ADA bridging ELISA using antibody HCA235.


In figure 4, a microtiter plate was coated overnight with omalizumab at a concentration of 1 µg/ml. After washing and blocking with PBST + 5% BSA, PBST with or without 10% human serum was added spiked with increasing concentrations of Human Anti-Omalizumab Antibody, clone AbD20669_hIgG1 (HCA235). Detection was performed using HRP conjugated omalizumab. Data are shown as the mean of three measurements. Addition of serum changes the binding curve of the assay due to presence of endogenous IgE, which interferes with the assay. HRP conjugation of omalizumab was performed using a LYNX Rapid HRP Antibody Conjugation Kit.

Protocol: Omalizumab ADA bridging ELISA using antibody HCA235


Demonstration of Drug-Target Complex Antibody Specificity

Fig. 5. Specificity of Human Anti-Omalizumab/hIgE Antibody.

Drug-target complex specific antibodies HCA237 and HCA238 detect omalizumab only when bound to its target hIgE; they do not detect omalizumab or hIgE alone. In figure 5, a microtiter plate was coated overnight with various antigens at a concentration of 5 μg/ml. After washing and blocking with PBST + 5% BSA, detection was performed using HRP conjugated Human Anti-Omalizumab/IgE Antibody, clone AbD20760_hIgG1  (HCA237P) at a concentration of 2 μg/ml and QuantaBlu Fluorogenic Peroxidase Substrate.


Licensed Use: For in vitro research purposes and for commercial applications for the provision of in vitro testing services to support preclinical and clinical drug development. Any re-sale in any form or any other commercial application needs a written agreement with Bio-Rad.