Host cell proteins (HCPs) are proteins produced or encoded by the host organisms used to produce recombinant therapeutic proteins (1). Recombinant therapeutic proteins are usually produced by genetically-modified host cells using cell culture or fermentation technology (2). During the recombinant protein production, host cells also coproduce proteins related to the normal cell functions such as cell growth, proliferation, survival, gene transcription, protein synthesis, and etc. Other non-essential proteins may also be released to the cell culture or fermentation as a result of cell apoptosis/death/lysis (2). HCPs constitute a most important part of process-related impurities during recombinant therapeutic proteins production. The amount of residual HCPs in drug product is generally considered a critical quality attribute (CQA), due to their potential to affect product safety and efficacy. Therefore, it is a regulatory requirement to monitor the removal of HCPs in drug product during bioprocess development. The DeQuanto E. Coli HCP ELISA kit is an ELISA based immunoassay. The HCPs present in the sample or standard binds to pre coated Anti E. Coli HCPs antibodies on polystyrene microtiter plate. Non bound or the excess substances are removed by washing. Horseradish Peroxidase (HRP) labeled Anti E. Coli HCPs antibodies is added to the well which binds to the HCPs/Anti E. Coli antibodies complex in the wells. Following a wash to remove any unbound antibody-enzyme reagent, substrate solution is added to the wells. A color product is formed in proportion to the amount of HCPs present in the sample or standards. The color development is stopped by addition of a stop solution. The absorbance is measured at 450 nm in a microtiter plate reader. The concentration of HCPs in a sample can be interpolated from the standard curve.

ACCURACY AND PRECISION: Inter and intra assay precision %RE 10%

SENSITIVITY: LLOQ is 12.5 ng/ml MRD: Neat sample

DILUTION LINEARITY: Tested and passes with %RE 10%

ASSAY RANGE: 3052 ng/ml to 6.25 ng/ml

ASSAY TIME: 3-4 Hours