Host cell protein, HCP

Trace contaminants such as host cell proteins (HCPs) and DNA are deterrnined by more specialized techniques. Host cell proteins are generally deterrnined using an immunochemical assay, in which an antibody preparation, raised against a mixture of the HCPs, is used to selectively detect the total level of HCPs in the product. DNA can be deterrnined using a labeled mixture, or probe, of complimentary DNA from the host cell. 

Polishing final purification step (invariably using chromatography) to remove dose product-related impurities, residual of host cell proteins (HCPs) and endotoxins. 

Typically, biotechnology products have been produced in cell lines not of human origin. In such cases, residual host cell proteins (HCP) are perceived as a safety concern to the patient. In the case of... 

This part will mainly focus on host cell proteins (HCPs) quantification. Process-specific HCP assays are in general targeted to be in place prior to the initiation of phase III clinical trials. Immunoassays are the most specific and sensitive techniques available for detecting and quantifying protein impurities. There are two methods commonly employed to quantify protein impurities in biopharmaceuticals enzyme-linked immunosorbent assays (ELISA) and immunoligand assays (ILA). Both methods are able to detect very low ppm level of impurities. ELISA have been developed to measure host protein impurities in a number of recombinant proteins including human growth hormone (Anicetti et ah, 1986), insulin (Baker et al, 1981) and staphylokinase (Wan et ah, 2002). ILA assays have been used to detect protein impurities in recombinant bovine somatotropin (Whitmire and Eaton,... 

Table 3. Residual content of is. coli OmpA and host cell proteins in pilot batches of P40. P40 bulks E. coli OmpA contend HCP contend...

Of all the possible contaminants and impurities of a biopharmaceutical product, organisms (bacteria, virus, mycoplasma) and their products (DNA, endotoxin, host protein), media components, and raw materials, it is most appropriate to use an ELISA for the HCP impurities and some of the process residuals (media components and raw materials). Impurities from media components are known or expected unlike those from the host cell. 

Host Cell Impurities Various organisms have been used to produce recombinant proteins yeast, bacteria (e.g., E. coli), insect cells, and mammalian cells such as Chinese hamster ovary (CHO) cells. During the purification process, some HCPs can copurify with the protein product. Because of the specificity of the antigen-antibody interaction, an ELISA can be used to detect and quantitate the contaminating HCPs. Detecting host impurities is important for quality process control as well as for product safety issues. The intent is to avoid unsafe levels of residual HCPs which might lead to adverse reactions.11... 

In the development of an ELISA for host cell impurities, you also have to consider copurification of a HCP that is homologous to the product the host species version of the recombinant protein, e.g., urokinase, is known to be present in many continuous cell lines.3 Due to the similarity in structure, it is possible that an endogenous homologous protein molecule could copurify with the desired product.3... 

We have developed and validated a process-specific ILA assay based on the Threshold system of the company Molecular Devices for strain-specific host cell-derived E. coli protein contaminants in in-process and purified lots of BBG2Na (Dagouassat et ah, 2001a). This assay is based upon use of rabbit anti-HCP polyclonal antibodies derived from null cells. A manufacturing scale preparation of HCP was made starting with cell paste of... 

---