Association of fever with late-onset pulmonary hypersensitivity responses in the guinea pig

Abstract

The guinea pig model of pulmonary hypersensitivity, developed in this laboratory, was used to study the relationship of fever with late-onset airway responses (LAR). The preceding paper M. H. Karol, J. A. Hillebrand, and P. S. Thorne. (1989). Toxicol. Appl. Pharmacol. 100, 234-246 described production of immediate-onset responses (IAR) to ovalbumin (OA) with infrequent production of LAR (Karol et al., 1989). In the current study, LAR was produced on each of two occasions in the same animals using a sensitization regimen consisting of ip injection with 1 mg OA followed by exposure to 63 mg/m3 OA aerosol on Day 8. On Days 15 and 29, pyrilamine maleate was administered prior to inhalation challenges to block H1 receptors and to allow exposure for 20 min to 63 mg/m3 OA without histamine shock and fatal anaphylactic reactions. Each of the seven guinea pigs demonstrated IAR; four of seven additionally underwent LAR on both occasions. Late-onset responses were maximal at 4-5 hr postchallenge. Febrile responses of approximately 1°C (maximum 1.6°C) accompanied the LAR in six of seven cases. Histopathology performed at the height of response revealed peribronchiolar eosinophilia. Pulmonary function determination indicated airflow disturbance during exhalation. These results are consistent with LAR being an airway response which is accompanied by fever and demonstrate the applicability of the guinea pig animal model to the study of mechanisms underlying IAR and LAR hypersensitivities. © 1989.