Passive sensitization of mice and rats with IgE antibodies.

The strain-dependent variation in susceptibility to passive sensitization of the skin and peritoneal mast cells with homologous IgE antibodies was observed in inbred strains of mice. Strain 129 showed low susceptibility to passive sensitization and high efficiency of normal serum in blocking mouse reagin-induced PCA in rats. Balb/c and C3H/A strains showed higher susceptibility to passive sensitization and the efficiency of normal serum in blocking rat PCA lower than strain 129. The serum factor responsible for rat PCA inhibiting effect was heat-labile. The anaphylactic response of peritoneal mast cells of inbred strains to the challenge with anti-mouse IgE and anti-rat IgE in vitro was low in Balb/c mice, as compared with the response of C57BL/6J and 129 mice. The results suggest, that non-specific IgE present in the serum or bound to the mast cells may be one of the factors determining the susceptibility of mouse strains to reagin-induced passive sensitization. However, the results obtained with C57BL/6J strain suggest the existence of other factors effecting this susceptibility.