title: Lack of microbiota reduces innate responses and enhances adaptive immunity against Listeria monocytogenes infection.
abstract: The intestinal microbiota influences not only metabolic processes, but also the mucosal and systemic immune systems. Here, we compare innate and adaptive immune responses against the intracellular pathogen Listeria monocytogenes in germfree (GF) and conventional mice. We show that animals without endogenous microbiota are highly susceptible to primary infection with impaired activation and accumulation of phagocytes to the site of infection. Unexpectedly, secondary infection with otherwise lethal dose resulted in survival of all GF animals which cleared bacteria more rapidly and developed a stronger antilisterial CD8(+) memory T-cell response compared to conventional mice. In summary, lack of the intestinal microbiota impairs early innate immunity, but enhances activation and expansion of memory T cells.
authors.affiliation: Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany; Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Hans-Willi
authors.initials: HW
authors.lastname: Mittrücker
authors.forename: Daniel
authors.initials: D
authors.lastname: Seidel
authors.forename: Paul W
authors.initials: PW
authors.lastname: Bland
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Zarzycka
authors.forename: Stefan H E
authors.initials: SH
authors.lastname: Kaufmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Visekruna
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinhoff
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D007113:Immunity, Innate; D007156:Immunologic Memory; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000276:immunology / Q000382:microbiology; D008089:Listeria monocytogenes / Q000276:immunology*; D008088:Listeriosis / Q000276:immunology* / Q000473:pathology; D051379:Mice; D064307:Microbiota / Q000276:immunology*
keywords: Innate immunity; Listeria infection; Memory T cells; Microbiota