Alpha-naphthyl acetate esterase-1 (ANAE-1) secreted by epithelioid cells from induced rabbit lung granuloma showed MIF activity

Involvement of tumor necrosis factor-alpha, interleukin-1 beta, interleukin-8, and interleukin-1 receptor antagonist in acute lung injury caused by local Shwartzman reaction

A local Shwartzman reaction (LSR) was prepared in rabbit lung as a model of acute lung injury. To induce LSR, intratracheal injection of lipopolysaccharide (LPS) 10 micrograms into the lower lobe of the right lung, followed 24 h later by i.v. injection of LPS (10 micrograms/kg). In the lung with the LSR, myeloperoxidase activity, representing neutrophil accumulation, peaked at 1-2 h and was sustained for 48 h after challenge with i.v. LPS. The lung water content peaked at 12 h, and decreased gradually. Histological findings showed diffuse interstitial widening, intra-alveolar leukocyte infiltration with hemorrhage, and alveolar exudate formation. The production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-8 (IL-8), and IL-1 receptor antagonist (IL-1 Ra) in the lung was analyzed. TNF-alpha first elevated and peaked at 0.5 h (66.5 +/- 16.7 ng/g.lung), subsequently, IL-1 beta and IL-8 increased and peaked at 2 h (17.8 +/- 3.4 ng/g.lung and 336.9 +/- 49.6 ng/g.lung, respectively). IL-1Ra was present even before the challenge, and the production increased to show a dual peak (0.5 h, 1.5 +/- 0.2 micrograms/g.lung; and 2 h, 1.6 +/- 0.1 micrograms/g.lung), and a large concentration of IL-1Ra was sustained for 48 h. Immunohistochemistry showed that the cellular source of these cytokines was alveolar macrophages and infiltrating neutrophils. Thus, disclosing the kinetics of the generation of cytokines led to a better understanding of their roles, namely TNF-alpha as an initiator, IL-1 and IL-8 as amplifier and effector, and IL-1Ra as regulator of the intensity of acute inflammation.

Identification of IL-1 inhibitory activity as IL-1 receptor antagonist (IL-1ra) in vitro and kinetics of IL-1ra and IL-1 beta in experimental rabbit lung granuloma

This study investigated whether interleukin-1 (IL-1) inhibitory activity in LPS-stimulated culture supernatants of alveolar macrophages and epithelioid cells obtained from rabbit lung granulomas induced by complete Freund's adjuvant (CFA) was identical to IL-1 receptor antagonist (IL-1ra) and examined the changes of IL-1ra and IL-1 beta levels in lung tissue during the natural course of granulomatous inflammation. In the thymocyte proliferation assay, prostaglandin E2 (PGE2)-free culture supernatants from each cell population revealed a bell-shaped IL-1 titration curve with IL-1 activity suppressed at dilutions of 1:1 to 1:2, and gel chromatography of serum-free culture supernatants showed an IL-1 inhibitory peak at 21-25 kD. Suppression of IL-1 activity in the supernatants at lower dilutions and the gel-purified IL-1 inhibitory activity both almost disappeared after IL-1ra depletion with an anti-rabbit IL-1ra immunoaffinity column, indicating that IL-1ra was responsible for this in vitro IL-1 inhibitory activity. Pulmonary tissue levels of IL-1 beta pecked at 24 h (52.0 +/- 9.5 pg/mg) after CFA injection, whereas IL-1ra levels peaked at 4 weeks (23.1 +/- 4.0 ng/mg) when granuloma development was maximal, and the molar excess of IL-1ra to IL-1 beta peaked from 4 weeks onward at over 800-fold. These observations suggest that IL-1ra may be effective for IL-1 regulation, especially in the later stage of granulomatous responses. Immunohistochemical studies demonstrated that the cellular source of IL-1ra within the pulmonary granulomas was mainly epithelioid cells.