Corazza N, Müller S, Brunner T, Kägi D, Mueller C
Institute of Pathology, Division of Immunopathology, University of Bern, Switzerland.
J Immunol. 2000 Jan 1;164(1):398-403. doi: 10.4049/jimmunol.164.1.398.
Intestinal intraepithelial lymphocytes (IELs) are known to exert strong constitutive cytotoxic activity. In the present study we compared the Ag-specific cytotoxic activity and the effector mechanisms involved in non-Ag-primed, naive and in in vivo-primed IELs and splenic CD8 T cells. Ex vivo isolated naive CD8alphaalpha TCRalphabeta IELs, CD8alphabeta IELs, and splenocytes from lymphocytic choriomeningitis virus (LCMV)-specific TCR transgenic mice exert Ag-specific cytotoxic activity in a long-term, but not in a short-term, cytotoxicity assay. This cytotoxic activity is mainly Fas-Fas ligand mediated and is significantly reduced in the presence of 20 microg/ml Fas-Fcgamma1 fusion protein. Both CD8alphabeta IELs and CD8alphabeta splenocytes isolated from LCMV-infected C57BL/6 mice exert potent perforin-dependent cell-mediated cytotoxicity. CD8alphaalpha TCRalphabeta IELs from LCMV-infected animals, however, show only minimal Ag-specific cytotoxicity. The potent cytotoxic activity of in vivo activated CD8alphabeta IELs is not affected by the addition of Fas-Fcgamma1. Nevertheless CD8alphabeta IELs from LCMV-infected perforin-deficient mice exert Ag-specific cytotoxicity in a short-term cytotoxicity assay, and this cytotoxicity is almost completely blocked by the addition of Fas-Fcgamma1. These results demonstrate that naive CD8alphabeta IELs exert Ag-specific, Fas-Fas ligand-mediated, constitutive cytotoxic activity in a long-term cytotoxicity assay, whereas primed CD8alphabeta IELs primarily use the perforin-dependent exocytosis pathway to exert their potent cytotoxic activity. Furthermore, these results clearly illustrate the requirement for Ag-specific determination of IEL-mediated cytotoxicity, because the elevated, but variable, frequencies of memory-type T cells in this compartment may lead to ambiguous results when polyclonal activation or redirected assays are used.
已知肠道上皮内淋巴细胞（IEL）具有强大的组成性细胞毒性活性。在本研究中，我们比较了未接触抗原的天然IEL以及体内已接触抗原的IEL和脾CD8 T细胞的抗原特异性细胞毒性活性及其效应机制。从淋巴细胞性脉络丛脑膜炎病毒（LCMV）特异性TCR转基因小鼠中体外分离的天然CD8αα TCRαβ IEL、CD8αβ IEL和脾细胞，在长期细胞毒性试验中表现出抗原特异性细胞毒性活性，但在短期细胞毒性试验中则不然。这种细胞毒性活性主要由Fas - Fas配体介导，并且在存在20μg/ml Fas - Fcγ1融合蛋白的情况下显著降低。从感染LCMV的C57BL / 6小鼠中分离的CD8αβ IEL和CD8αβ脾细胞均发挥强大的穿孔素依赖性细胞介导的细胞毒性。然而，来自感染LCMV动物的CD8αα TCRαβ IEL仅表现出最小的抗原特异性细胞毒性。体内活化的CD8αβ IEL的强大细胞毒性活性不受添加Fas - Fcγ1的影响。尽管如此，来自感染LCMV的穿孔素缺陷小鼠的CD8αβ IEL在短期细胞毒性试验中发挥抗原特异性细胞毒性，并且这种细胞毒性几乎完全被添加Fas - Fcγ1所阻断。这些结果表明，天然CD8αβ IEL在长期细胞毒性试验中发挥抗原特异性、Fas - Fas配体介导的组成性细胞毒性活性，而已接触抗原的CD
