Minutello M A, Pileri P, Unutmaz D, Censini S, Kuo G, Houghton M, Brunetto M R, Bonino F, Abrignani S
Immunobiology Research Institute, Siena, Italy.
J Exp Med. 1993 Jul 1;178(1):17-25. doi: 10.1084/jem.178.1.17.
The adult liver is an organ without constitutive lymphoid components. Therefore, any intrahepatic T cell found in chronic hepatitis should have migrated to the liver after infection and inflammation. Because of the little information available on the differences between intrahepatic and peripheral T cells, we used recombinant proteins of the hepatitis C virus (HCV) to establish specific T cell lines and clones from liver biopsies of patients with chronic hepatitis C and compared them with those present in peripheral blood mononuclear cells (PBMC). We found that the protein nonstructural 4 (NS4) was able to stimulate CD4+ T cells isolated from liver biopsies, whereas with all the other HCV proteins we consistently failed to establish liver-derived T cell lines from 16 biopsies. We then compared NS4-specific T cell clones obtained on the same day from PBMC and liver of the same patient. We found that the 22 PBMC-derived T cell clones represent, at least, six distinct clonal populations that differ in major histocompatibility complex restriction and response to superantigens, whereas the 27 liver-derived T cell clones appear all identical, as further confirmed by cloning and sequencing of the T cell receptor (TCR) variable and hypervariable regions. Remarkably, none of the PBMC-derived clones has a TCR identical to the liver-derived clone, and even with polymerase chain reaction oligotyping we did not find the liver-derived clonotypic TCR transcript in the PBMC, indicating a preferential intrahepatic localization of these T cells. Functionally, the liver-derived T cells provided help for polyclonal immunoglobulin (Ig)A production by B cells in vitro that is 10-fold more effective than that provided by the PBMC-derived clones, whereas there is no difference in the help provided for IgM and IgG production. Altogether these results demonstrate that the protein NS4 is highly immunogenic for intrahepatic CD4+ T cells primed by HCV in vivo, and that there can be compartmentalization of some NS4-specific CD4+ T cells to the liver of patients with chronic hepatitis C.
成体肝脏是一个没有组成性淋巴成分的器官。因此，在慢性肝炎中发现的任何肝内T细胞都应是在感染和炎症后迁移至肝脏的。由于关于肝内T细胞和外周T细胞之间差异的可用信息很少，我们利用丙型肝炎病毒（HCV）的重组蛋白，从慢性丙型肝炎患者的肝活检组织中建立了特异性T细胞系和克隆，并将它们与外周血单个核细胞（PBMC）中的T细胞系和克隆进行比较。我们发现，蛋白非结构4（NS4）能够刺激从肝活检组织中分离出的CD4+ T细胞，而对于所有其他HCV蛋白，我们始终未能从16份活检组织中建立肝源性T细胞系。然后，我们比较了同一天从同一患者的PBMC和肝脏中获得的NS4特异性T细胞克隆。我们发现，22个源自PBMC的T细胞克隆至少代表六个不同的克隆群体，它们在主要组织相容性复合体限制和对超抗原的反应方面存在差异，而27个源自肝脏的T细胞克隆看起来全部相同，T细胞受体（TCR）可变区和高变区的克隆及测序进一步证实了这一点。值得注意的是，源自PBMC的克隆中没有一个具有与源自肝脏的克隆相同的TCR，即使通过聚合酶链反应寡核苷酸分型，我们也未在PBMC中发现源自肝脏的克隆型TCR转录本，这表明这些T细胞优先定位于肝脏。在功能上，源自肝脏的T细胞在体外为B细胞产生多克隆免疫球蛋白（Ig）A提供的帮助比源自PBMC的克隆提供的帮助有效10倍，而在为IgM和IgG产生提供的帮助方面则没有差异。总之，这些结果表明，蛋白NS4对体内由HCV引发的肝内CD4+ T细胞具有高度免疫原性，并且一些NS4特异性CD4+ T细胞可在慢性丙型肝炎患者的肝脏中出现分隔化。
