Peptide vaccine for killer T cell induction against hepatitis C virus

丙型肝炎病毒(HCV)蛋白中存在多种细胞毒性T淋巴细胞(CTL)表位。CTL在控制丙型肝炎病毒感染中可能起重要作用。在此，我们在丙型肝炎病毒核心蛋白中发现了一个高度保守的抗原位点，可被小鼠和人的CTL识别。H-2^d小鼠的CTL对单一的16个残基的合成肽(丙型肝炎病毒129-144)有反应。这个保守的表位由小鼠的主要组织相容性分子(H-2D^d)呈现给常规的CD_4~+-CD_8~+CTL，由表达D^d、L^d或K^d的转染体定位，但不被H-2^b限制的CTL所识别，小鼠的表位被映射到十肽LMGYIPLVGA。2例急性a-…患者HLAA2阳性患者的细胞毒性T细胞更多的慢性丙型肝炎病毒识别由人类白细胞抗原A2呈递的9个残基片段(DLMGYIPLV)，该片段含有一个与人类白细胞抗原A2结合的基序，只有1个残基超出了小鼠的表位。因此，这一保守的多肽，在小鼠CTL和具有非常普遍的HLAI类分子的人CTL中被看到，可能是针对广泛的丙型肝炎病毒分离株的丙型肝炎疫苗的一个有价值的成分。这项研究表明，在人类研究之前对小鼠的CTL表位进行筛选可能是有用的。动物模型中的疫苗开发取决于识别人类T细胞所见表位的能力。在这项工作中，我们表明，在表达人HLA-A2.1的转基因小鼠中，CTL反应可以前瞻性地预测11个丙型肝炎病毒(HCV)结构蛋白衍生多肽中的4个，这些多肽表达与人类A2.1限制的CTL实际上识别的HLA-A2.1结合的序列基序。CTL还识别内源性表达这些蛋白质的靶标。来自丙型肝炎病毒感染患者的人类CTL，用相同的多肽进行测试，显示出几乎相同的反应谱。高度保守的丙型肝炎病毒核心肽是最具免疫原性的，并且可能是针对人类白细胞抗原A2阳性患者的多种丙型肝炎病毒分离株的疫苗的有价值的组成部分。这些结果表明，尽管物种不同，T细胞谱系具有足够的可塑性，当相同的I类MHC分子呈现多肽时，可以产生类似的反应。因此，人类白细胞抗原分子在决定CTL识别哪些多肽方面起着主要作用。该转基因小鼠模型对于研究人类白细胞抗原限制性CTL决定簇和设计潜在的丙型肝炎疫苗具有重要意义。较少

Several cytotoxic T-lymphocyte (CTL) epitopes have been defined in hepatitis C virus (HCV) proteins. CTL may play an important role in the control of infection by HCV.Here, we identify a highly conserved antigenic site in the HCV core recognized by both murine and human CTL.Spleen cells from mice immunized with a recombinant vaccinia virus expressing the HCV core gene were restimulated in vitro with 11 peptides from the core protein. CTL from H-2^d mice responded to a single 16-residue synthetic peptide (HCV 129-144). This conserved epitope was presented by a murine class I major histocompatibility molecule (H-2D^d) to conventional CD4^- CD8^+ CTL mapped by using transfectants expressing D^d, L^d, or K^d, but was not seen by CTL restricted by H-2^b. The murine epitope was mapped to the decapeptide LMGYIPLVGA.The same 16-residue peptide was recognized by CTL from two HCV-seropositive patients but not by CTL from any scronegative donors. CTL from two HLA-A2-positive patients with acute a … More nd chronic hepatitides C recognized a 9-residue fragment (DLMGYIPLV) of the peptide presented by HLA-A2 and containing an HLA-A2-binding motif, extending only 1 residue beyond the murine epitope. Therefore, this conserved peptide, seen with murine CTL and human CTL with a very prevalent HLA class I molecule, may be a valuable component of an HCV vaccine against a broad range of HCV isolates. This study demonstrates that the screening for CTL epitopes in mice prior to human study may be useful.Vaccine development in animal models depends on ability to recognize epitopes seen by human T cells. In this work, we show that CTL responses in transgenic mice expressing human HLA-A2.1 prospectively predict the same four of 11 hepatitis C virus (HCV) structural protein-derived peptides, expressing a sequence motif for HLA-A2.1 binding, that are actually recognized by human A2.1-restricted CTLs. The CTLs also recognized targets endogenously expressing these proteins. Human CTLs from HCV-infected patients, tested by using the same peptides, revealed a virtually identical response repertoire. A highly conserved HCV core peptide was the most immunogenic, and may-be a valuable component of a vaccine against a broad range of HCV isolates in HLA-A2-positive patients. These results suggest that, in spite of species differences, the T cell repertoire is plastic enough to allow a similar response when the same class I MHC molecule is presenting the peptide. Thus, the HLA molecule plays the primary role in determining which peptides are recognized by CTLs. This transgenic mouse model is important for the study of HLA-restricted CTL determinants and for an approach to design a potential HCV vaccine. Less