Yasukawa M, Ohminami H, Yakushijin Y, Arai J, Hasegawa A, Ishida Y, Fujita S
First Department of Internal Medicine and Department of Pediatrics, Ehime University School of Medicine, Shigenobu, Ehime, Japan.
J Immunol. 1999 May 15;162(10):6100-6.
The present study was undertaken to clarify the mechanisms of cytotoxicity mediated by virus-specific human CD4+ CTLs using the lymphocytes of family members with a Fas gene mutation. CD4+ CTL bulk lines and clones directed against HSV-infected cells were established from lymphocytes of a patient with a homozygous Fas gene mutation and of the patient's mother. HSV-specific CD4+ CTLs generated from lymphocytes of the patient and her mother exerted cytotoxicity against HSV-infected cells from the patient (Fas-/-) and from her mother (Fas+/-) to almost the same degree in an HLA class II-restricted manner. mRNAs for the major mediators of CTL cytotoxicity, Fas ligand, perforin, and granzyme B, were detected in these CD4+ CTLs using the RT-PCR and flow cytometry. The cytotoxicity of the HSV-specific CD4+ CTLs appeared to be Ca2+-dependent and was almost completely inhibited by concanamycin A, a potent inhibitor of the perforin-based cytotoxic pathway. Although the Fas/Fas ligand system has been reported to be the most important mechanism for CD4+ CTL-mediated cytotoxicity in the murine system, the present findings strongly suggest that granule exocytosis, not the Fas/Fas ligand system, is the main pathway for the cytotoxicity mediated by HSV-specific human CD4+ CTLs.
本研究旨在利用具有Fas基因突变的家庭成员的淋巴细胞，阐明病毒特异性人类CD4⁺CTL介导的细胞毒性机制。从一名纯合Fas基因突变患者及其母亲的淋巴细胞中建立了针对HSV感染细胞的CD4⁺CTL群体系和克隆。患者及其母亲的淋巴细胞产生的HSV特异性CD4⁺CTL以HLA II类限制性方式对来自患者（Fas⁻/⁻）及其母亲（Fas⁺/⁻）的HSV感染细胞发挥几乎相同程度的细胞毒性。使用RT-PCR和流式细胞术在这些CD4⁺CTL中检测到CTL细胞毒性的主要介质Fas配体、穿孔素和颗粒酶B的mRNA。HSV特异性CD4⁺CTL的细胞毒性似乎依赖于Ca²⁺，并且几乎完全被基于穿孔素的细胞毒性途径的有效抑制剂 concanamycin A抑制。尽管Fas/Fas配体系统据报道是小鼠系统中CD4⁺CTL介导的细胞毒性的最重要机制，但本研究结果强烈表明，颗粒胞吐作用而非Fas/Fas配体系统是HSV特异性人类CD4⁺CTL介导的细胞毒性的主要途径。
