Sensitive and specific immunoradiometric assays for human interleukin-1 alpha.

In order to estimate human IL-1 alpha in physiological samples we have established sensitive and specific immunoradiometric assays using monoclonal and polyclonal antibodies. Solid phase assays employing two different monoclonal antibodies were suitable for estimating rDNA derived IL-1 alpha but were relatively insensitive. Sensitivity was increased by using a monoclonal antibody to capture antigen and 125I-labelled polyclonal sheep antibodies to develop the assay. This assay could detect as little as 20pg/ml IL-1 alpha and could be used for assaying antigen in monocyte supernatants, in human skin extracts and in joint fluid from patients with inflammatory disease. It was entirely specific for IL-1 alpha and was unaffected by non-IL-1 alpha components present in serum. It is therefore suitable for monitoring IL-1 alpha concentrations in the circulation of patients undergoing therapy with the monokine.