Involvement of IL-18 in the expansion of unique hepatic T cells with unconventional cytokine profiles during Schistosoma mansoni infection.
Infection with schistosomes invokes severe fibrotic granulomatous responses in the liver of the host. Schistosoma mansoni infection induces dramatic fluctuations in Th1 or Th2 cytokine responses systemically; Th1 reactions are provoked in the early phase, whilst Th2 responses become dominant after oviposition begins. In the liver, various unique immune cells distinct from those of conventional immune competent organs or tissues exist, resulting in a unique immunological environment. Recently, we demonstrated that S. mansoni infection induces unique CD4+ T cell populations exhibiting unconventional cytokine profiles in the liver of mice during the period between Th1- and Th2-phases, which we term the transition phase. They produce both IFN-γ and IL-4 or both IFN-γ and IL-13 simultaneously. Moreover, T cells secreting triple cytokines IFN-γ, IL-13 and IL-4 were also induced. We term these cells Multiple Cytokine Producing Hepatic T cells (MCPHT cells). During the transition phase, when MCPHT cells increase, IL-18 secretion was up-regulated in the liver and sera. In S. mansoni-infected IL-18-deficient mice, expansion of MCPHT cells was curtailed. Thus our data suggest that IL-18 produced during S. mansoni infection play a role in the expansion of MCPHT cells.
Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Global Center of Excellence Program, Nagasaki University, Nagasaki, Japan.
Keishi
K
Adachi
Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
Risa
R
Nakamura
Department of Immunology and Parasitology, The University of Occupational and Environmental Health, Kitakyushu, Japan.
Yoshio
Y
Osada
Department of Pathology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
Masachika
M
Senba
Department of Immunology and Cell Signaling Analysis, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Koji
K
Tamada
Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Global Center of Excellence Program, Nagasaki University, Nagasaki, Japan.
Shinjiro
S
Hamano
D000818:Animals; D005260:Female; D020382:Interleukin-18 / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000276:immunology* / Q000378:metabolism / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D012550:Schistosoma mansoni; D012555:Schistosomiasis mansoni / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000469:parasitology
D020382:Interleukin-18