Niederwieser D, Grassegger A, Auböck J, Herold M, Nachbaur D, Rosenmayr A, Gächter A, Nussbaumer W, Gaggl S, Ritter M
Department of Internal Medicine, University of Innsbruck, Austria.
Blood. 1993 Apr 15;81(8):2200-8.
Peripheral blood mononuclear cells (PBMC) from 17 patients receiving HLA-identical sibling bone marrow grafts were stimulated with host pretransplant PBMC. Cytotoxic T-cell lines (TCL) with specificity for host pretransplant PBMC were obtained from 9 of these patients, all presenting with severe graft-versus-host disease (GVHD), but from none of the remaining cases lacking evidence of disease. Cytotoxic TCL were specific for host targets and failed to lyse donor cells. Monoclonal antibodies (MoAbs) blocking experiments and donor population screening analyses demonstrated that minor histocompatibility antigen (MiHA)-specific lysis of host targets was restricted by class I major histocompatibility complex (MHC) determinants. Whereas hematopoietic cells such as phytohemagglutinin (PHA) blasts or lymphoblastoid cell lines were susceptible to lysis by MiHA-specific TCL, keratinocytes (K) representing the natural targets of GVHD were quite resistant. Quantitative radioimmunometric measurements indicated very low constitutive expression of class I MHC antigens on K targets, which was readily increased by treatment with interferon-gamma (IFN-gamma). IFN-gamma treatment at the same time rendered these cells susceptible to lysis by MiHA-specific TCL. Host leukemic cells of 3 patients were recognized by MiHA-specific TCL in a chromium release assay and in one experiment host leukemic cells were effectively killed and their growth specifically inhibited in a leukemia colony assay by a clone. These data demonstrate that (1) host-specific cytotoxic TCL are detected exclusively in the PB of patients with acute GVHD grades II through IV after allogeneic matched bone marrow transplantation, and (2) their target antigens are simultaneously expressed on several host cell lines, including lymphoblastoid cell lines, PHA blasts, leukemic cells, and K. We also extend previous findings by showing that, besides the expression of the nominal MiHA, the density of the restricting class I MHC elements also crucially determines the extent of TCL lysis. Because of its capacity to enhance class I MHC antigen expression, IFN-gamma represents a key cytokine for determining the susceptibility of MiHA targets for lysis by TCL and clones, and in one patient an MiHA-specific clone recognized host leukemic cells and also inhibited host leukemic cell growth in a colony inhibition assay.
用宿主移植前的外周血单个核细胞（PBMC）刺激17例接受 HLA 相同同胞骨髓移植患者的外周血单个核细胞（PBMC）。从其中9例患者获得了对宿主移植前PBMC具有特异性的细胞毒性T细胞系（TCL），所有这些患者均出现严重移植物抗宿主病（GVHD），而其余未出现疾病证据的病例均未获得。细胞毒性TCL对宿主靶细胞具有特异性，不能裂解供体细胞。单克隆抗体（MoAb）阻断实验和供体群体筛选分析表明，宿主靶细胞的次要组织相容性抗原（MiHA）特异性裂解受 I 类主要组织相容性复合体（MHC）决定簇限制。虽然造血细胞如植物血凝素（PHA）刺激的细胞或淋巴母细胞系易被MiHA特异性TCL裂解，但代表GVHD天然靶细胞的角质形成细胞（K）则相当耐受。定量放射免疫测定表明，K靶细胞上I类MHC抗原的组成性表达非常低，用干扰素-γ（IFN-γ）处理后其表达很容易增加。IFN-γ处理同时使这些细胞易被MiHA特异性TCL裂解。在铬释放试验中，3例患者的宿主白血病细胞被MiHA特异性TCL识别，在一项实验中，宿主白血病细胞在白血病集落试验中被一个克隆有效杀伤，其生长受到特异性抑制。这些数据表明：（1）宿主特异性细胞毒性TCL仅在异基因匹配骨髓移植后急性GVHD II至IV级患者的外周血中检测到；（2）它们的靶抗原同时在几种宿主细胞系上表达，包括淋巴母细胞系、PHA刺激的细胞、白血病细胞和K。我们还扩展了先前的发现，表明除了名义上的MiHA表达外，限制性I类MHC元件的密度也至关重要地决定了TCL裂解的程度。由于其增强I类MHC抗原表达的能力，IFN-γ是决定MiHA靶细胞对TCL和克隆裂解敏感性的关键细胞因子，在一名患者中，一个MiHA特异性克隆识别宿主白血病细胞，并在集落抑制试验中抑制宿主白血病细胞生长。
