Marijt W A, Veenhof W F, Goulmy E, Willemze R, van Rood J J, Falkenburg J H
Department of Hematology, University Medical Center, Leiden, The Netherlands.
Blood. 1993 Dec 15;82(12):3778-85.
HLA-identical bone marrow transplantation (BMT) may be complicated by graft-versus-host disease or graft rejection. Both complications are thought to be initiated by recognition of minor histocompatibility (mH) antigens by HLA-restricted mH-antigen-specific T lymphocytes. Using HLA-A2-restricted mH antigens HA-1-, -2-, and -4-, and HY-specific cytotoxic T lymphocyte (CTL) clones, we studied the recognition by these CTL clones of interleukin-2 (IL-2)-stimulated T cells (IL-2 blasts), BM mononuclear cells (BMMNCs), and hematopoietic progenitor cells (HPCs). We showed that, when IL-2 blasts from the BM donors who were investigated were recognized by the HA-1-, -2-, and -4-, and HY-specific CTL clones, their BMMNCs and HPCs were recognized as well by these CTL clones, resulting in antigen-specific growth inhibition of erythrocyte burst-forming units (BFU-E), colony-forming units-granulocyte (CFU-G), and CFU-macrophage (CFU-M). the HA-2-specific CTL clone, however, inhibited BFU-E and CFU-G growth from four donors to a lesser extent than from two other donors. We further investigated whether inhibitory cytokines released into the culture medium by the antigen-specific stimulated CTLs or by stimulated BMMNCs were responsible for suppression of HPC growth or whether this effect was caused by direct cell-cell contact between CTLs and HPCs. HPC growth inhibition was only observed after preincubation of BMMNCs and CTLs together for 4 hours before plating the cells in semisolid HPC culture medium. When no cell-cell contact was permitted before plating, neither antigen-stimulated CTL nor antigen-nonstimulated CTLs provoked HPC growth inhibition. Culturing BMMNCs in the presence of supernatants harvested after incubation of BMMNCs and CTL clones together for 4 or 72 hours did also not result in HPC growth inhibition. Both suppression of HPC growth and lysis of IL-2 blasts and BMMNCs in the 51Cr-release assay appeared to be dependent on direct cell-cell contact between target cells and CTLs and were not caused by the release of inhibitory cytokines into the culture medium by antigen-specific stimulated CTLs or by stimulated BMMNCs. Our results show that mH-antigen-specific CTLs can inhibit HPC growth by a direct cytolytic effect and may therefore be responsible for BM graft rejection after HLA-identical BMT.
人类白细胞抗原（HLA）相合的骨髓移植（BMT）可能会并发移植物抗宿主病或移植物排斥反应。这两种并发症被认为是由HLA限制性微小组织相容性（mH）抗原特异性T淋巴细胞识别mH抗原引发的。利用HLA - A2限制性mH抗原HA - 1、- 2和- 4以及HY特异性细胞毒性T淋巴细胞（CTL）克隆，我们研究了这些CTL克隆对白细胞介素-2（IL - 2）刺激的T细胞（IL - 2母细胞）、骨髓单个核细胞（BMMNCs）和造血祖细胞（HPCs）的识别情况。我们发现，当来自被研究的骨髓供体的IL - 2母细胞被HA - 1、- 2、- 4和HY特异性CTL克隆识别时，它们的BMMNCs和HPCs也会被这些CTL克隆识别，从而导致红细胞爆式集落形成单位（BFU - E）、粒细胞集落形成单位（CFU - G）和巨噬细胞集落形成单位（CFU - M）的抗原特异性生长抑制。然而，HA - 2特异性CTL克隆对来自四个供体的BFU - E和CFU - G生长的抑制程度低于对另外两个供体的抑制程度。我们进一步研究了抗原特异性刺激的CTL或刺激的BMMNCs释放到培养基中的抑制性细胞因子是否是HPC生长受抑制的原因，或者这种效应是否是由CTL与HPC之间的直接细胞间接触引起的。只有在将BMMNCs和CTL一起预孵育4小时后再接种到半固体HPC培养基中，才观察到HPC生长受到抑制。如果在接种前不允许细胞间接触，那么无论是抗原刺激的CTL还是未受抗原刺激的CTL都不会引发HPC生长抑制。在BMMNCs与CTL克隆一起孵育4或72小时后收集的上清液存在的情况下培养BMMNCs，也不会导致HPC生长抑制。在51Cr释放试验中，HPC生长抑制以及IL - 2母细胞和BMMNCs的裂解似乎都依赖于靶细胞与CTL之间的直接细胞间接触，而不是由抗原特异性刺激的CTL或刺激的BMMNCs释放抑制性细胞因子到培养基中所导致的。我们的结果表明，mH抗原特异性CTL可通过直接细胞溶解作用抑制HPC生长，因此可能是HLA相合BMT后骨髓移植物排斥反应的原因。
