CHO HCP ELISA
The Chinese hamster ovary (CHO) cell line is the most prevalent biopharmaceutical expression system and has been proven safe for the commercial production of protein therapeutics. To ensure the safety of recombinantly expressed biopharmaceuticals, health authorities are demanding the close monitoring of HCP impurities by applying HCP detection methods with high sensitivity and specificity. The BioGenes’ CHO|360-HCP ELISA is an enhanced generic HCP assay composed of four different generic kits, and was designed to cover a broader spectrum of CHO-HCPs compared to single generic kits.
Four CHO Kit Types
The CHO|360-HCP ELISA kits (Type A to D) are based on a unique assay design, employing differently prepared HCP antigens and antibodies from two animal species:
- The antigen is prepared from total and fractionated HCP obtained from mock fermentation of CHO-K1 and CHO-S
- The specific antibodies are generated by parallel immunization of goats and rabbits
CHO|360-HCP ELISA Performance
The CHO|360-HCP ELISA method was qualified at BioGenes according to the respective ICH-Guideline ICH Q2(R1).
High specificity of all four antibody preparations (A to D) was demonstrated by a coverage of ≥ 80% of the CHO|360-HCP antigen population in 1D and 2D analysis. For each CHO|360-HCP ELISA kit (A to D), the recovery rate was estimated in the three spiked samples within the assay working range and with an acceptance criterion of 100±30% of spiked antigen recovered.
The high sensitivity of CHO|360-HCP ELISA Kits (A to D) is demonstrated by the validation parameters LOD and working range, as shown below:
- Limit of Detection (LOD): ≤ 1.0 ng/mL
- Working range: ～2 – 100 ng/mL
Qualification Report for BioGenes' CHO HCP ELISA
Why Does BioGenes Apply HCP Fractionation Prior to Immunization?
Naturally, low molecular weight (LMW) proteins are less immunogenic than larger proteins, leading to a reduced production of anti-LMW HCP antibodies after the immunization of animals. Consequently, very weakly immunogenic or non-immunogenic HCPs may not be detected by ELISA or Western Blot. The BioGenes' CHO|360-HCP ELISA lessens this potential disadvantage by using total or fractionated HCP for the immunization of animals, resulting in four different HCP ELISA kits (A to D).
Antibodies obtained from immunization with each of three different molecular-weight fractions were then pooled again to combine antibody reactivity towards the complete HCP spectrum. The immunization of rabbits and goats enables the generation of distinct antibody panels, which allows for a broader coverage of HCPs in customized samples.
BioGenes' recommendation: We recommend testing all four kit types (Starter Set) first, and then selecting the best performing kit according to ELISA key parameters (such as dilution linearity, accuracy and total coverage) for use in all subsequent tests.