Journal of Applied Physiology, Vol 69, Issue 3 1012-1021, Copyright © 1990 by American Physiological Society
Late pulmonary allergic responses in actively but not passively IgE-sensitized rats
R. Sorkness, K. Johns, W. L. Castleman and R. F. Lemanske Jr
Department of Medicine and Pediatrics, School of Medicine, University of Wisconsin, Madison 53706.
Previous studies suggested that although rats that were passively
sensitized [monoclonal murine immunoglobulin E (IgE)] would respond to
pulmonary antigen challenge with an immediate increase in resistance, they
exhibited no late increases in resistance, unlike late changes in rats
actively sensitized to preferentially produce IgE antibody. We hypothesized
that passively sensitized rats also would not develop antigen-induced
pulmonary inflammation. In a blinded protocol we compared immediate
responses and pulmonary resistance and inflammation at 8, 19 and 24 h after
challenge with placebo antigen, with dinitrophenol-bovine serum albumin
(DNP-BSA) to elicit a passively sensitized response, or with ovalbumin (OA)
to elicit an actively sensitized response. Despite similar immediate
responses to OA and DNP-BSA, only the rats challenged with OA had marked
inflammatory changes and a significant incidence of late elevations in
resistance. Inflammation scores and lung resistance were significantly
correlated only in the OA group. We also observed that anesthesia with
fentanyl/droperidol significantly attenuated the immediate but not the late
responses to antigen challenge, compared with rats anesthetized with
ketamine. We conclude that IgE-mediated immediate responses to pulmonary
antigen challenge are insufficient, and may be unnecessary, to initiate
antigen-induced late inflammatory changes.
