Mohagheghpour N, Gammon D, Kawamura L M, van Vollenhoven A, Benike C J, Engleman E G
Kuzell Institute for Arthritis and Infectious Diseases, California Pacific Medical Center Research Institute, San Francisco 94115, USA.
J Immunol. 1998 Sep 1;161(5):2400-6.
The successful resolution of infection with Mycobacterium tuberculosis (M.tb) is believed to involve the induction of CTLs that are capable of killing cells harboring this pathogen, although little information is known about the MHC restriction or fine specificity of such CTLs. In this study, we used knowledge of the HLA-A0201-binding motif and an immunofluorescence-based peptide-binding assay to screen for potential HLA-A0201-binding epitopes contained in the 19-kDa lipoprotein of M.tb (M.tb19). CD8+ T cells derived from HLA-A0201+ patients with active tuberculosis (TB) as well as tuberculin skin test-positive individuals who had no history of TB were used as effector cells to determine whether these epitopes are recognized by in vivo-primed CTLs. An in vitro vaccination system using HLA-A0201+ dendritic cells (DCs) as APCs was used to determine whether these epitopes can sensitize naive CD8+ T cells in vitro, leading to the generation of Ag-specific CTLs. The results show that an HLA-A*0201-binding peptide comprised of residues 88 to 97 of M.tb19 (P88-97) is recognized by circulating CD8+ CTLs from both healthy tuberculin skin test-positive individuals and patients with active TB but not by tuberculin skin test-negative subjects. Moreover, dendritic cells pulsed with this peptide induced class I MHC-restricted CTLs from the T cells of healthy unsensitized persons. Finally, CTL lines that were specific for P88-97 were shown to lyse autologous monocytes that had been infected acutely with the H37Ra strain of M.tb. These results demonstrate that M.tb19 elicits HLA class I-restricted CTLs in vitro and in vivo that recognize endogenously processed Ag. Epitopes of the type identified here may prove useful in the design of an M.tb vaccine.
结核分枝杆菌（M.tb）感染的成功清除被认为涉及诱导能够杀死携带这种病原体的细胞的细胞毒性T淋巴细胞（CTL），尽管关于此类CTL的主要组织相容性复合体（MHC）限制或精细特异性知之甚少。在本研究中，我们利用HLA-A0201结合基序的知识和基于免疫荧光的肽结合试验，筛选M.tb 19 kDa脂蛋白（M.tb19）中潜在的HLA-A0201结合表位。来自HLA-A0201+活动性结核病（TB）患者以及无TB病史的结核菌素皮肤试验阳性个体的CD8+T细胞用作效应细胞，以确定这些表位是否被体内致敏的CTL识别。使用HLA-A0201+树突状细胞（DC）作为抗原呈递细胞（APC）的体外疫苗接种系统，以确定这些表位是否能在体外使未致敏的CD8+T细胞致敏，从而产生抗原特异性CTL。结果显示，由M.tb19的88至97位残基组成的HLA-A*0201结合肽（P88-97）可被健康结核菌素皮肤试验阳性个体和活动性TB患者的循环CD8+CTL识别，但不能被结核菌素皮肤试验阴性受试者识别。此外，用该肽脉冲的树突状细胞从健康未致敏者的T细胞诱导出I类MHC限制的CTL。最后，对P88-97特异的CTL系显示可裂解急性感染M.tb H37Ra株的自体单核细胞。这些结果表明，M.tb19在体外和体内均可引发识别内源性加工抗原的HLA I类限制的CTL。此处鉴定的此类表位可能在M.tb疫苗设计中证明有用。
