title: Listeriolysin O is a target of the immune response to Listeria monocytogenes.
abstract: The immunologic mechanism of protective immunity to the intracellular parasite Listeria monocytogenes (Lm) is not well understood, however, antilisterial immunity can be adoptively transferred with T lymphocytes from Lm-immune donors. The Lm-immune cells are believed to produce macrophage-activating lymphokines, which leads to the eventual macrophage-dependent eradication of the bacterium. Increasing evidence suggests that immunity to Lm resides exclusively within the CD8+ T cell subset. It is possible that the Lm-immune CD8+ T cells function to release sequestered Lm from nonprofessional phagocytes to awaiting activated macrophage populations. This study was conducted to determine if listeriolysin O (LLO), which is an essential determinant of Lm pathogenicity, is also a target of the antilisterial immune response. We have found that target cells infected with a LLO+ Lm strain are lysed by Lm-immune cytotoxic cells, whereas target cells infected with a LLO- Lm mutant, or pulsed with a heat-killed Lm preparation, are not lysed by the Lm-immune effector cells. We have used a Bacillus subtilis (Bs) construct that expresses the LLO gene product and found that target cells infected with the LLO+ Bs construct are lysed by antilisterial cytotoxic cells. The antilisterial cytotoxic response is targeted against LLO, in that we have also used a Bs construct that expresses the perfringolysin (PLO) gene product and found that target cells infected with the PLO+ Bs are not lysed by antilisterial cytotoxic effector cells. These data strongly suggest that LLO is a target antigen of antilisterial immunity and may represent the dominant target during the expression of the immune response to Lm.
authors.affiliation: Earle A. Chiles Research Institute, Providence Medical Center, Portland, Oregon 97213.
authors.forename: H G
authors.initials: HG
authors.lastname: Bouwer
authors.forename: C S
authors.initials: CS
authors.lastname: Nelson
authors.forename: B L
authors.initials: BL
authors.lastname: Gibbins
authors.forename: D A
authors.initials: DA
authors.lastname: Portnoy
authors.forename: D J
authors.initials: DJ
authors.lastname: Hinrichs
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001427:Bacterial Toxins; D020126:Brefeldin A; D002460:Cell Line; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D005260:Female; D006360:Heat-Shock Proteins / Q000276:immunology*; D006460:Hemolysin Proteins / Q000276:immunology*; D007114:Immunization; D008089:Listeria monocytogenes / Q000276:immunology*; D008088:Listeriosis / Q000276:immunology*; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D003517:Cyclopentanes; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D020126:Brefeldin A; C038705:hlyA protein, Listeria monocytogenes