Stability of anti-drug antibodies in human serum samples.

Stability of anti-drug antibodies (ADAs) is important as ADA-analysis should be reliable over time at different storage conditions. Stability of anti-insulin antibodies in serum samples was assessed after short-term storage at different temperatures and after long-term storage at -20 °C. Correlation between measurements was tested and acceptance criteria for incurred sample reanalysis were applied. ADAs were stable after 72 h at 22 °C, after 2 weeks at 4 °C, and after 6.3 years at -20 °C. The study confirms that ADAs in serum are stable for several years at -20 °C and suggests that investigation of short- and long-term stability of ADAs is not needed if samples are handled at standard laboratory-conditions.

An ELISA for detection of complement-bound circulating immune complexes in mice.

Measurements of complement-bound circulating immune complexes (cCICs) in pre-clinical studies may provide important information about the etiology of certain pathology findings suggestive of being immune complex mediated. This article describes the development and qualification of a universal methodology to measure cCIC in mice after dosing with species foreign proteins. The assay is a sandwich enzyme-linked immunosorbent assay - exclusively based on commercially available reagents - that could detect mouse IgG bound to complement C3 independent of the test-substance present in the plasma sample. Heat-aggregated serum was used as positive control. The assay was qualified by assessment of acceptance criteria, stability of positive control, precision, and specificity. Finally, the performance of the assay was tested using plasma from mice administered either of three different proteins, i.e bovine serum albumin (BSA), a fully human monoclonal antibody, and a humanized monoclonal antibody.