In situ activation of mouse alveolar macrophages by aerosolized liposomal interferon-[gamma] and muramyl tripeptide. Goldbach, P., S. Dumont, R. Kessler, P. Poindron, and A. Stamm. Laboratoire de Pharmacotechnie and Laboratoire d'Immunologie et Immunopharmacologie, U.F.R. des Sciences Pharmaceutiques, Universit[acute]e Louis Pasteur, BP 24, 67401 Illkirch Cedex (France), Service de Pneumologie, H[circumflex]opitaux Universitaires, 67098 Strasbourg Cedex (France)
APStracts 2:0181L, 1995.
Interferon-g (IFN-g) was entrapped with an efficiency of 30-40% in muramyl tripeptide-containing liposomes by a freeze-thawing procedure. A microcytotoxicity assay was developed to measure the tumoricidal activity of mouse alveolar macrophages (AM) against tumoral target cells with a colorimetric viability test. Free IFN-g and liposomal muramyl tripeptide phosphadityl-ethanolamine (MTP-PE) were found to be only slightly effective to activate in vitro AM, whereas encapsulation of both IFN-g and MTP-PE within the same liposomes produced higher activation of AM. Aerosolized IFN-g and liposomal immunomodulators enhanced antitumor properties of AM recovered in mice 24 h post-inhalation. Whereas free IFN-g also induced a substantial activation of peritoneal macrophages, liposomal encapsulation significantly reduced the systemic activity of inhaled immunomodulators. This approach provides an useful model for the compartmentalized organ-specific activation of AM in mice.

Received 29 December 1994; accepted in final form 17 September
1995.
APS Manuscript Number L372-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95