Austin Taylor M, Bennett M, Kumar V, Schatzle J D
Graduate Program in Immunology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
J Immunol. 2000 Nov 1;165(9):5048-53. doi: 10.4049/jimmunol.165.9.5048.
NK cells are the primary effectors mediating acute rejection of incompatible bone marrow cell grafts. To reduce rejection, we evaluated the ability of chloroquine (CHQ) to prevent perforin-dependent NK cell activity. Perforin is a key cytotoxic component released from the lytic granules of activated NK cells. Generation of functional perforin requires an acidic protease activity that occurs in the secretory, lytic lysosomes. Our hypothesis was that CHQ, a lysosomotropic reagent, would raise the pH of the acidic compartment in which perforin is processed and thereby block perforin maturation and cytotoxicity. We have measured NK cytotoxicity in vivo by clearance of YAC-1 tumor cells from the lungs and by rejection of incompatible bone marrow transplants and in vitro by cytolysis of YAC-1 and Jurkat cells. The engraftment of bone marrow cells was monitored by recolonization of the spleen with hemopoietic cells from transplants of MHC class I-deficient bone marrow cells into lethally irradiated recipient mice. Transplant rejection was compared in two inbred strains of mice: 129, which apparently use perforin-dependent cytotoxicity, and C57BL/6, in which rejection can be perforin-independent. CHQ treatment reduced NK cell activity in 129 mice in which perforin is important for mediating rejection. CHQ affected the fraction of NK cell cytolysis that was Fas independent. In addition, we found that CHQ prevents perforin processing by LAK cells in vitro. These data indicate that CHQ may impair rejection of incompatible bone marrow transplants and other functions mediated by NK and cytotoxic T cells.
自然杀伤细胞（NK细胞）是介导不相容骨髓细胞移植急性排斥反应的主要效应细胞。为了减少排斥反应，我们评估了氯喹（CHQ）抑制穿孔素依赖性NK细胞活性的能力。穿孔素是活化NK细胞溶解颗粒释放的关键细胞毒性成分。功能性穿孔素的产生需要酸性蛋白酶活性，这种活性发生在分泌性溶酶体中。我们的假设是，作为一种溶酶体亲和试剂，CHQ会提高穿孔素加工所在酸性区室的pH值，从而阻断穿孔素的成熟和细胞毒性。我们通过清除肺部的YAC-1肿瘤细胞和排斥不相容的骨髓移植在体内测量NK细胞毒性，并通过YAC-1和Jurkat细胞的细胞溶解在体外测量NK细胞毒性。通过将MHC I类缺陷骨髓细胞移植到经致死性照射的受体小鼠中，用造血细胞重新定殖脾脏来监测骨髓细胞的植入情况。在两种近交系小鼠中比较移植排斥反应：129小鼠，显然利用穿孔素依赖性细胞毒性；C57BL/6小鼠，其排斥反应可能不依赖穿孔素。CHQ处理降低了129小鼠的NK细胞活性，在这些小鼠中穿孔素对介导排斥反应很重要。CHQ影响了不依赖Fas的NK细胞细胞溶解比例。此外，我们发现CHQ在体外可阻止LAK细胞对穿孔素的加工。这些数据表明，CHQ可能会损害不相容骨髓移植的排斥反应以及由NK细胞和细胞毒性T细胞介导的其他功能。
