TCR Transgenic Mice: A Valuable Tool for Studying Viral Immunopathogenesis Mechanisms
1）However, due to large T cell receptor (TCR) diversity (1 × 10的13方), complete and precise analyses of viral antigen-specific T-cell responses are almost impossible.
2）Diverse TCR Tg mice expressing TCRs specific for viral antigens of LCMV, influenza virus, RSV, WNV, HBV, TMEV, HSV, and MCMV have been generated to contribute to understanding mechanisms of viral immunopathogenesis (Table 1).
Lymphocytic Choriomeningitis (LCMV)
a single-stranded RNA genome
mice are its natural host，给小鼠转入识别LCMV的TCR
Since LCMV is a non-cytolytic virus, it is possible to accurately measure the cytotoxic activity by the host anti-viral immune response
T cell–DC coculture（PMID: [23023500]）
Naïve CD4+ T cells (25×103 cells) labeled with 5 µM carboxy-fluorescein diacetate succinimidyl ester (CFSE; Molecular Probes) were cultured with 0.5×103 DC and indicated concentration of toxic shock syndrome toxin 1 (TSST-1, Toxin Technology).
miRNA quantification：using a mirVana™ qRT-PCR miRNA detection kit (Applied Biosystems).Briefly, 25 ng of RNA from isolated T cells was reverse-transcribed in 10 µl at 37°C for 30 min using a miRNA- or U6-specific oligonucleotide.
腹腔注射（Intraperitoneal Injections，IP）
i.v.尾静脉注射
by plaque assay on Vero cells.
activated CD62L– CD44+ CD8 T cells
检测T细胞器官：肝脏，脾脏，淋巴结
T细胞活性标志：interferon gamma (IFNγ)-, tumor necrosis factor alpha (TNFα)- or interleukin 2 (IL-2)-producing
检测病毒滴度的地方：肾，脾脏
CD4 T细胞通常是作为是免疫系统中的“辅助”角色，它们大多数情况并不能直接中和感染，而是引导并触发机体对感染源的免疫应答，类似于免疫系统的“哨兵”。在CD启动免疫应答后，后再由CD8T细胞来扮演“行刑官”的角色，清除感染源（包括被HIV感染的CD4细胞）。
In antiviral T cell responses, CD8 T cells differentiate into memory precursor and short-lived effector T cells that can be distinguished based on variable expression of CD127 (IL-7Rα) and KLRG1 (Joshi et al., 2007; Sarkar et al., 2008).
T细胞的发育、分化和成熟
胸腺是T细胞分化、发育的主要场所，胸腺微环境是诱导并调控该过程的关键因素[4]。早期的胸腺细胞表面为不表达CD4、CD8分子的双阴性细胞（DN），DN细胞在向深皮质迁移的过程中，逐渐发生T细胞受体（TCR）α、β基因重排和表达，双阴性细胞免于凋亡，并发育为CD4+、CD8+ 双阳性细胞（DP）。DP细胞α链基因发生重排，开始表达有功能性的TCR，CD3表达水平逐渐上升。TCR可以与自身肽-主要组织相容性复合体(MHC)分子进行识别和结合。随后DP细胞经历阳性选择：DP细胞与胸腺基质细胞表面的MHC若不能结合或结合力过高，则发生凋亡；若结合力适当，则存活并转变为单阳性细胞（SP）。SP细胞分为两类，能与MHCⅠ类分子结合的分化为CD4-CD8+ 细胞，与MHCⅡ类分子结合的分化为CD4+CD8- 细胞，经过这一过程，两类SP细胞分别获得对MHC限制性（MHC restriction）识别能力。随后T细胞移至胸腺皮质与髓质的交界处进行阴性选择；单阳性细胞若能与局部树突状细胞（DC）或巨噬细胞表面的自身MHC分子复合物高亲和力结合，即被诱导凋亡或失能;反之，则继续分化、发育，成为仅能识别非己抗原的T细胞。
细胞免疫应答是一个连续的过程，可分为三个阶段：①T细胞特异性识别抗原阶段；②T细胞活化、增殖和分化阶段；③效应性T细胞的产生及效应阶段。在免疫应答过程中，还有部分活化T细胞分化为记忆T细胞（memory T cell）[
