Chemiluminescent and Enzyme-Linked Immuno Assays for Sensitive Detection of Human IFN-γ

Abstract

We have produced and characterized 4 mAbs to human IFN-γ and established sensitive, non-radioactive immuno-assays. The first two assays use microtiter plates as the solid phase and enzymes or chemiluminescence (acridinium ester) for development. The use of chemiluminescence instead of peroxidase increased the sensitivity of the assay by a factor of about 75. The third and the fourth assays utilize polystyrene beads as the solid phase and enzymes or acridinium ester for development. The use of beads also increased the sensitivity of detection. The most sensitive IFN-γ detection was achieved by the combination of bead with acridinium ester. In this configuration we were able to detect about 0.2 pg/ml IFN-γ (1/250th of a unit). These chemiluminescent immunoassays (CLIA) appear to be more sensitive than existing ELISAs or radioimmunoassays and may find new application areas.