Analysis of the Serum IgE Levels in Nonimmunized Rats of Various Strains by a Radioimmunoassay

Abstract

An assay, the paper radioimmunosorbent test (PRIST) for the measurement of total serum IgE in the rat, that allows the measurement of IgE down to a level of 0.25 ng/ml, is described. With this assay it has been demonstrated that significant differences exist in normal serum IgE levels in non‐immunized rats. These differences are strain‐dependent, and strains may be classified as to low (300 ng/ml) serum levels. The serum IgE level is not sex‐dependent. Environmental factors have a pronounced influence, optimal housing conditions resulting in low and stable levels while suboptimal conditions result in high levels with great fluctuations. Hybridization experiments suggest a multigenic control, with low IgE strains having a dominating suppressor effect.