HuCAL® Fab antibodies can be converted into full length human or chimeric antibodies when an Fc region is required for your application. The variable heavy and light chain genes are cloned into vectors with the desired constant regions and co-transfected for expression in mammalian cells. Antibodies are purified and tested by quality control ELISA.

Conversion of HuCAL Fab antibody to full length immunoglobulin


Fig. 1. Overview of the process for conversion of Fab to immunoglobulin.

Fully human HuCAL immunoglobulins (Igs) of various isotypes are expressed in a human cell line, with secure long term supply. This makes them ideal for bioanalytical assays supporting biotherapeutic development and as surrogates for human sera controls and calibrators in immunoassay applications.

Table 1. Choice of Fc region for full immunoglobulin format.

Human

IgG1, IgG2, IgG3, IgG4
IgG4Pro (mutation in core hinge region that prevents the formation of IgG4 half molecules)
IgA, IgE, IgM

Other species

On request e.g. mouse, rat, rabbit

There are three options for obtaining your antibodies in Ig format:

1.  
Receive all Fab antibodies generated from your project

  • Test all in your application
  • Select your preferred candidates for conversion to Ig
  • Order from Bio-Rad
  • Available for all isotypes in table 1
  • Up to 1 mg of each antibody supplied (IgM as supernatant, all other isotypes purified)

2.  
Receive all Fab antibodies generated from your project

  • Test all in your application
  • Select your preferred candidates for conversion to Ig
  • Order the Fab antibody gene sequences for your selected antibodies from Bio-Rad
  • Carry out the cloning, expression and purification in your own lab

3.  
Opt to have a number of Fab antibodies from your project converted directly, without testing the Fabs in your application

  • Receive the full Ig antibodies for testing
  • Available for human IgG1, IgG2 and IgG4
  • Conversion of 4, 8, 10 or 12 antibodies in parallel
  • Up to 0.2 mg of each antibody initially supplied for testing

Custom Services Available

Catalog Number

Conversion of one Fab antibody to full Ig format and test expression of up to 1 mg, all isotypes available

CAB11571

Conversion of 4, 8, 10 or 12 Fab antibodies in parallel to full Ig format and microscale expression of up to 0.2 mg; IgG1, IgG2, IgG4

CAB11603

Production of Ig antibody, 250 µg

CAB11558

Production of Ig antibody, per mg

CAB11559

Antibody DNA and amino acid sequence, light chain, Fd chain and tags in electronic format

CAB11582



Critical reagents for bioanalytical assays

With HuCAL technology it is possible to develop a single high-affinity antibody for use in Fab and/or Ig format for pharmacokinetic (PK) studies. In the fully human Ig format it can also be used as a calibrator for immunogenicity testing, or anti-drug antibody (ADA) assays. This eliminates the need for patient or animal sera and greatly reduces assay development time and effort.

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).

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.

PK assay, bridging format, using anti-cetuximab antibodies HCA220 and HCA221.

PK assay, bridging format, using anti-cetuximab antibodies HCA220 and HCA221.

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).
 

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).

ADA assay bridging format, using anti-cetuximab antibodies HCA221, HCA222 and HCA223.

ADA assay bridging format, using anti-cetuximab antibodies HCA221, HCA222 and HCA223.

Fig. 2. Examples of the use of HuCAL antibodies in full immunoglobulin format in PK and ADA assays.



Controls for autoimmune and infectious disease assays

HuCAL immunoglobulins have been successfully used to replace patient sera as a consistent, secure, and fully characterized source of control human antibodies for immunoassays.


Publication: Knappik A et al. (2009). Development of recombinant human IgA for anticardiolipin antibodies assay standardization. Ann N Y Acad Sci. 1173:190-8