Zhu Fenlu, Yang Meiying, Eckels David D
Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, P.O. Box 26509, Milwaukee, WI 53226-0509, USA.
Vaccine. 2005 May 20;23(27):3572-80. doi: 10.1016/j.vaccine.2005.01.157.
The premise of this work is that within a given hepatitis C virus (HCV) protein there exists an array of Th1 and Th2 epitopes, each of which can provide synergistic (positive or negative) effects upon other epitopes by intramolecular, cytokine-mediated immunoregulation of helper T-cell responses. To address this question, we constructed minigene plasmids pHCVTh1, pHCVTh1X3 and pHCVThR, and HCV NS3 full-length plasmid pHCVNS3. 293T cells were transfected with these plasmids and cell lysates from the transfected cells were used to stimulate PBMC from a patient with chronic HCV infection. IL-2 and IFN-gamma in the supernatant of the cultured PBMC were tested and proliferation of the PBMC was measured. The results demonstrate that interactions exist among helper T-cell epitopes; the synergistic effects of suppressive Th2 epitopes upon Th1 epitopes will inhibit the responses induced by Th1 epitopes, which may contribute to chronic infection by HCV; synergistic effects among Th1 epitopes induce higher levels of IFN-gamma, which may suggest a new strategy for HCV vaccine development. Further, stimulation of an HCV NS3 specific clone with cell lysates from 293T cells transfected with different constructs shows that the HCV NS3 clone could respond to all suggesting that the epitope-specific suppression may be due to an imbalance of Type 1 and Type 2 cytokines or regulatory T-cells.
这项研究的前提是，在给定的丙型肝炎病毒（HCV）蛋白中存在一系列Th1和Th2表位，通过辅助性T细胞应答的分子内细胞因子介导的免疫调节，每个表位可对其他表位产生协同（正向或负向）作用。为解决这一问题，我们构建了小基因质粒pHCVTh1、pHCVTh1X3和pHCVThR，以及HCV NS3全长质粒pHCVNS3。用这些质粒转染293T细胞，并用转染细胞的细胞裂解物刺激慢性HCV感染患者的外周血单个核细胞（PBMC）。检测培养的PBMC上清液中的白细胞介素-2（IL-2）和γ干扰素（IFN-γ），并测定PBMC的增殖情况。结果表明，辅助性T细胞表位之间存在相互作用；抑制性Th2表位对Th1表位的协同作用会抑制Th1表位诱导的应答，这可能导致HCV慢性感染；Th1表位之间的协同作用诱导更高水平的IFN-γ，这可能提示了一种HCV疫苗开发的新策略。此外，用转染了不同构建体的293T细胞的细胞裂解物刺激HCV NS3特异性克隆，结果显示HCV NS3克隆对所有刺激均有反应，这表明表位特异性抑制可能是由于1型和2型细胞因子或调节性T细胞失衡所致。
