Answer: The development of generic HCP ELISA kits involves the following steps:
- Immunization of individuals using a particular antigen material
- Isolation of polyclonal antibodies and purification
- Manufacturing of ready-to-use ELISA kits
Many different suppliers offer generic kits, using their own development strategy concerning the cell line and fermentation conditions applied for antigen preparation and the animal species used for immunization. This usually results in one generic HCP assay which provides just a single antibody that must work for all manufacturing processes.
For a more reliable HCP detection, we have developed the enhanced generic 360-HCP ELISA approach. For the detection of HCPs in biologics produced in CHO or E. coli cells, BioGenes offers four different kit types each using different sets of anti-HCP antibodies.
In the case of CHO kit development, the antigen is obtained from combined mock material from the fermentation of CHO-K1 and CHO-S cells. The antibody generation differs in the preparation of the antigen material (fractionation or not) and the immunized species (rabbit or goat). Fractionation is performed to enhance the generation of antibodies against low molecular weight proteins, which are generally less immunogenic than larger proteins. Immunization is performed individually with three different molecular-weight fractions and the obtained antibodies are pooled again for complete HCP spectrum.
| CHO Kits | Species | HCP | E. coli Kits | Cell line | Growth medium | |
|---|---|---|---|---|---|---|
| Type A | Goat | Total | Type A 2G | BL21 (DE3) | Mineral Medium | |
| Type B | Goat | Fractionated | Type E | W3110 | Mineral Medium | |
| Type C | Rabbit | Total | Type D 2G | BL21 (DE3) | LB Medium | |
| Type D | Rabbit | Fractionated | Type C | W3110 | LB Medium |
For the development of the E. coli HCP kits, different cell lines and growth media are combined since different E. coli strains show great genetic diversity and gene expression is highly dependent on growth conditions. Antibodies against E. coli HCPs are generated by immunization of rabbits (type A, D and E) and goats (type C).
The multi-kit approach enables the direct comparison of different antibody compositions and the selection of the antibody panel reflecting the relevant HCP impurities most adequately. For a comprehensive comparison BioGenes also offers a performance study to identify the most suitable kit for your manufacturing process.