In recent years, with the upgrading of upstream cell culture in biopharmaceutical, the cell density used to express target products has been increasing, resulting in higher levels of impurities (such as cell debris, HCP, HCD, etc.) in the fermentation broth. 

Host Cell Protein

Refers to the protein components produced by cell lines used in the production of biologics, which are complex mixtures with various physiochemical and immunological properties. And they are the main impurities related to the process.

Due to the involvement of many components in host cell protein synthesis, their residues may have potential immunogenicity during the administration process of biological products, leading to severe immune reactions in patents. Especially in the production of mAb and gene therapy products, HCP residues are non-target proteins produced by cell host during the production process, which may trigger immune responses in the body and affecting the safety and efficacy of biological products.

In addition to safety, the presence of HCPs can also affect products quality, such as protein aggregation, fragmentation and degradation of therapeutic proteins, which an affect the stability of protein products. 

Host Cell Residual DNA

Refers to the trace amount of nucleic acid (host genome, plasmid or total DNA) remaining in protein products expressed and purified through cell culture, and its sources include the host cell genome and plasmid. It has potential risk because the host cell residual DNA may transmit tumor or virus related genes. 

HCP, HCD Removal Methods

In the production of biological products, HCP and HCD levels are generally reduced through the following purification steps: depth filtration, affinity chromatography, ion exchange chromatography and mixed chromatography, etc.

New Iterative Depth Filters of Cobetter

Cobetter depth filters use high-purity wood fibers as the skeleton, diatomite and other filter aids as the filtration medium. The new iterative filters are optimized based on the original ionic adhesive, making it has better adsorption effect on small impurities, while having little effect on the yield of the products.

H6HPPC continues to enhance the original positive charge adsorption effect, while H4HPPC not only enhances the original positive charge adsorption effect, but also increases negative charge adsorption effect. H4HPPC has good adsorption effect on certain positively charged HCPs.

Advantages & Case study of Cobetter Iterative Depth Filters

Higher impurities removal capability

①Case Study I 

Experimental materials: CHO fermentation broth, with a live cell density of 18x106 cells/ml, activity rate 83%, turbidity>3300NTU
Filtration information: 

Results:

According to the above data, in this project:
Turbidity control ability: H4HPPC>H6HPPC>H2HPPC
HCP removal ability: H4HPPC>H6HPPC=H2HPPC
HCD removal ability: H4HPPC>H6HPPC>H2HPPC

②Case Study II

Experimental materials: CHO fermentation broth, with a live cell density of 6.4x106 cells/ml, activity rate 83%, centrifugation, turbidity 158NTU
Filtration information: 

Results:

According to the above data, in this project:
Turbidity control ability: H6HPPC>H4HPPC
HCP removal ability: H4HPPC>H6HPPC
HCD removal ability: H4HPPC>H6HPPC

③ Case Study III

Experimental materials: CHO fermentation broth, Low pH & Neutralization treatment, turbidity 12.2NTU

Filtration information: 

Results:

According to the above data, in this project:
Turbidity control ability: H6HPPC>H4HPPC
HCP removal ability: H4HPPC>H6HPPC
HCD removal ability: H6HPPC>H4HPPC

Cobetter iterative depth filters H4HPPC and H6HPPC have better performance than regular H2HPPC in turbidity control and impurity removal, but have relatively lower loading capacity compared to H2HPPC.