Reconstituting National Institute for Biological Standards and Control (NIBSC) chemokines

We observed significant discrepancies between immunoassay results when using different internally prepared reference preparations for interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) from the National Institute for Biological Standards and Control (NIBSC). To evaluate the reasons for this we prepared the chemokines using diluents that incorporated protein at different steps. This showed that even brief addition of water to these preparations, in the absence of additional protein, resulted in loss of immunoreactivity in assays. The data obtained emphasise the importance of adding protein at an early stage of preparation to avoid loss of material and potential loss of activity.