The kinetics of in vivo sensitization of rat peritoneal and lung mast cells: temporal dissociation from circulating levels of IgE.

Abstract

Following i.p. injection of ovalbumin (OVA) plus Bordetella pertussis vaccine into Hooded Lister rats, the time-course of sensitization of peritoneal and lung mast cells (MC) did not parallel kinetic changes in the levels of circulating OVA-specific and total IgE. OVA-induced secretion of 5-hydroxytryptamine from isolated peritoneal and lung MC and the presence of OVA-specific IgE in serum were first demonstrated at day 14 post-immunization. However, subsequent to day 14, the responsiveness of both types of MC to OVA declined, while circulating levels of OVA-specific IgE continued to rise. Peritoneal MC, but not lung MC, showed increased responsiveness to challenge with anti-IgE on day 7 post-immunization, whereas circulating levels of total IgE were not elevated until day 14, thus demonstrating that nonantigen-specific IgE was acquired by peritoneal MC before it entered the circulation. Lung MC generally showed decreased reactivity to both OVA and anti-IgE, compared with peritoneal MC; no significant correlations were demonstrated between the responses of MC from these two tissue sites.