Detection of human IL-1α and IL-1β at the subpicomolar level by colorimetric sandwich enzyme immunoassay

Abstract Two separate convenient sandwich enzyme immunoassay methods were developed for measuring the production of the monokines interleukin-1α (IL-1α) and interleukin-1β (IL-1β) from peripheral blood mononuclear cells. Polyclonal antisera raised against the recombinant proteins and selected on the basis of their ability to neutralize IL-1-induced IL-2 secretion were used for coating microtiter plates or preparing peroxidase-Fa′ conjugates. Both techniques were able to accurately and specifically detect monokines from various sources in the sub-picomolar range and were not influenced by compounds currently used for cell activation. A high molecular weight form of IL-1β was demonstrated under certain conditions and the two enzyme immunoassays were successfully applied to the detection of IL-1α and IL-1β present in cell supernatants following stimulation with mitogenic or chemical agents.