title: Kinetics of interferon-gamma secretion and its regulatory factors in the early phase of acute graft-versus-host disease.
abstract: Increased serum levels of interferon-gamma (IFN-gamma) have been observed in acute graft-versus-host disease (GVHD). Recent in vitro studies have demonstrated that interleukin-12 (IL-12) and interleukin-18 (IL-18) synergistically up-regulate IFN-gamma secretion. In this communication, we investigated the factors relevant to IFN-gamma secretion in acute GVHD. A murine model of acute GVHD was established by injecting donor spleen cells into severe combined immunodeficiency (SCID) mice. A series of specimens, including sera, livers and spleens derived from the GVHD mice, were investigated with histological examination, enzyme-linked immunosorbent assay (ELISA), flow cytometry, and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). IFN-gamma secretion increased in serum 3 days after spleen cell transfer, peaked on day 7, and then gradually decreased close to the baseline level by day 35. A synchronized increase of activated T cells and mRNA expression of IL-12, IL-18 and their respective receptors was observed after spleen cell transfer. However, only the kinetic expression pattern of IL-12 receptor (IL-12R) beta2 chains was closely correlated with that of IFN-gamma, while IL-12 dropped to the baseline level earlier than IFN-gamma. Therefore, IFN-gamma expression in the early phase of acute GVHD is a mono-peak and self-restricted pattern. Its secretion is closely related with T-cell activation, the presence of IL-12, IL-18 and their respective receptors. However, the limiting factors for IFN-gamma secretion seem to be IL-12 and IL-12R beta2 chains.
authors.affiliation: Department of Microbiology, Faculty of Medicine, National University of Singapore, Republic of Singapore.
authors.forename: H Z
authors.initials: HZ
authors.lastname: Hu
authors.forename: G L
authors.initials: GL
authors.lastname: Li
authors.forename: Y K
authors.initials: YK
authors.lastname: Lim
authors.forename: S H
authors.initials: SH
authors.lastname: Chan
authors.forename: E H
authors.initials: EH
authors.lastname: Yap
mesh_terms: D000208:Acute Disease; D000818:Animals; D005434:Flow Cytometry; D006086:Graft vs Host Disease / Q000276:immunology*; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism*; D018664:Interleukin-12 / Q000276:immunology*; D020382:Interleukin-18 / Q000097:blood / Q000378:metabolism; D016014:Linear Models; D008213:Lymphocyte Activation; D051379:Mice; D016513:Mice, SCID; D018123:Receptors, Interleukin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D020382:Interleukin-18; D018123:Receptors, Interleukin; D018664:Interleukin-12; D007371:Interferon-gamma