A comparison of five different methods for the detection of TNP specific mouse IgE: ELISA, ELISA on cells, rosetting, granule enzyme release assay and passive cutaneous anaphylaxis.

Using the same anti-TNP hybridoma supernatant pool as IgE antibody source (2 micrograms/ml), several methods were compared for their sensitivity in IgE detection and convenience for screening purposes. Using rat basophilic leukemia (RBL) cells as specific receptor cells, one out of two rosetting methods with TNP-sheep red blood cells allowed the detection of 0.5 ng IgE/ml (50 pg/assay) while the other was much less sensitive (60 ng/ml). More convenient for screening was an ELISA method performed on cells, in which the IgE bound to the RBL cell surface could be detected either by enzyme-anti-Ig or by enzyme-antigen conjugates with a similar, albeit low, sensitivity of 10 ng IgE/ml (500 pg/assay). Using the same antibody and cell sources, a very convenient and more sensitive method for screening purposes was found to be the measurement of antigen-induced basophil granule beta-N-acetylglucosaminidase release by IgE sensitized RBL cells: 0.5 ng IgE/ml and 50 pg/assay. For the same anti-TNP IgE source, this compares with a detection limit by ELISA of 0.2 ng IgE/ml (10 pg/assay) and by passive cutaneous anaphylaxis in rats of 2 ng IgE/ml (100 pg/assay).