Copyright © 1992 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Five groups of ten female guinea-pigs were passively sensitized against ovalbumin (OA) (n = 9) or control guinea-pig serum (n = 1). 24 h later, they received mepyramine (0.5 mg/kg, i.p.) and 30 min later inhaled aerosols of: (A) OA (2 in 0.9% saline, 8 min, n = 4/9); (B) saline (40 min, n = 4/9); (C) LPS (40 min, Escherichia coli 0111:B4, 150 ng/kg in PBS, n = 1/9); and (D) the control animal was treated as in (C) (n = 1). Their tracheas were cannulated under pentobarbital anaesthesia and bronchial alveolar lavage (BAL) was performed with 2 × 5 ml PBS containing BSA (1%) (n = 1 group), or BSA (1%) and aprotinin (1000 KIU/ml) (n = 4 groups), at 30, 60, 90 or 120 min post-inhalations. BAL fluids recovered were centrifuged, the supernatants recovered and frozen until assayed for tumour necrosis factor-α (TNF-α), interleukin-1 (IL-1) and interleukin-6 (IL-6). No TNF-α could be detected unless aprotinin was present in the lavaging solution. BAL fluid from OA-sensitized and control animals that had inhaled LPS contained high levels of TNF-α that peaked at 90 min. BAL fluid from OA sensitized animals that inhaled OA aerosols contained no detectable TNF-α at 30 min, but it was found in increasing amounts at 60, 90 and 120 min; TNF-α was not detected in fluid from any of the animals that inhaled saline. As BAL fluids were toxic to the cells used in the assays, neither IL-1 nor IL-6 could be measured. We conclude that the monokine TNF-α is released into BAL fluid following anaphylactic challenge of passively sensitized guinea-pigs. The presence of the antiprotease, aprotinin, in the lavaging solution is essential for the detection and measurement of TNF-α in BAL fluid.