Structural analysis of protective and non-protective T-cell epitopes encoded with in the retroviral gag gene product

逆转录病毒 gag 基因产物编码的保护性和非保护性 T 细胞表位的结构分析

基本信息

批准号：
13670305
负责人：
MIYAZAWA Masaaki
金额：
$ 0.51万
依托单位：
Kinki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

1) One of the mouse retroviral gag gene products, the N-terminal MA protein, contains multiple T-lymphocyte epitopes recognized by CD4-positive helper cells. One of these T-helper cell epitopes was mapped within amino acid residues 62 and 76, and another epitope was localized between residues 119 and 138 in the MA protein.2) CD4-positive T cells specifically reacting to the 62-76 epitope produced a large amount of IL-4, while T cells reactive to the epitope within 119-138 did not.3) To identify the antigenic structures that are required for protection against retroviral infection, various truncated forms of MA were expressed in a newly modified vaccinia virus vector, and mice were immunized with the resultant recombinant vaccinia viruses. All the truncated forms of MA lost the ability to protect mice, while the entire MA was effective. To elucidate if the truncation in the N-terminal portion affected the effectiveness of the whole MA due to the lack of the N-terminal residue required for protein myristylation, Gly at residue 2 was replaced with Ala in a mutant MA. This mutant MA localized in the cell nuclei, instead of cell membrane where myristylated proteins normally accumulate, and at the same time the vaccinia virus expressing this mutant MA lost its ability to protect mice against retroviral infection.4) Thus, myristylation of MA is necessary for its proper immunogenicity, and when myristylated, the Th2 epitope is not necessary, but an epitope in the C-terminal portion is required for protective efficacy of MA.

1）小鼠逆转录病毒GAG基因产物之一，N末端MA蛋白，包含CD4阳性辅助辅助辅助细胞识别的多个T淋巴细胞表位。这些T助是细胞表位之一被映射在氨基酸残基62和76中，并且在MA蛋白中，在残基119和138之间定位了另一个表位。2）CD4阳性T细胞特异性地与62-76表位反应的CD4阳性T细胞对IL-4产生了大量的IL-4，而eRe-eye do Protive of the Essig ofer not.e eye doperigy not.3 do e epen.3 do epen.3 do epen.3 do epen.3 do epen tosik for.3 do epen.33）针对逆转录病毒感染，在新修饰的疫苗病毒载体中表达了各种截短的MA形式，并用所得的重组疫苗病毒对小鼠进行免疫。所有被截断的MA形式都失去了保护小鼠的能力，而整个MA都是有效的。为了阐明由于缺乏蛋白肉豆蔻酰化所需的N末端残基，N末端部分的截断是否影响了整个MA的有效性，则在残基2处的GLY在突变体MA中被ALA代替。该突变体位于细胞核中，而不是细胞膜膜的蛋白质蛋白通常积聚，与此同时，表达该突变体MA的疫苗病毒失去了保护小鼠免受逆转录感染的能力。 MA的保护功效需要部分。