Immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various Archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen, Listeria monocytogenes

Protective immunity to intracellular bacterial pathogens usually requires t he participation of specific CD8+ T cells. Natural exposure of the host to sublethal infection, or vaccination with attenuated live vaccines are the m ost effective means of eliciting prolonged protective cell-mediated immunit y against this class of pathogens. The ability to replace these immunizatio n strategies with defined sub-unit vaccines would represent a major advance for clinical vaccinology. The present study examines the ability of novel liposomes, termed archaeosomes, made from the polar lipids of various Archa eobacteria to act as self-adjuvanting vaccine delivery vehicles for such de fined acellular antigens. Using infection of mice with Listeria monocytogen es as a model system, this study clearly demonstrates the ability of define d, archaeosome-entrapped antigens to elicit rapid and prolonged specific im munity against a prototypical intracellular pathogen. In this regard, all o f the tested archaeosomes were superior to conventional liposomes. Crown Co pyright (C) 2001 Published by Elsevier Science Ltd. All rights reserved.