Measurement of murine ovalbumin-specific IgE by a rat basophil leukemia cell serotonin release assay. Comparison to the rat passive cutaneous anaphylaxis assay.

A modified in vitro method to measure murine ovalbumin-specific IgE antibody as an alternative to the in vivo rat passive cutaneous anaphylaxis assay is presented in this report. This assay uses rat basophil leukemia (RBL) 2H3 cells that have been loaded with [3H]serotonin. Exposure of RBL-2H3 cells to mouse antisera and subsequent antigen challenge results in the release of [3H]serotonin. Using a monoclonal mouse anti-DNP IgE antibody and DNP-human serum albumin as the antigen, various steps of this assay were optimized to decrease the amount of time and reagents needed for the assay. The percent [3H]serotonin released was used to calculate antibody titer of sera from ovalbumin-immunized mice. Mouse anti-ovalbumin IgE titers determined by the RBL release method and passive cutaneous anaphylaxis assay were found to correlate very well over a wide range of antibody titers (correlation coefficient, r2 = 0.94).