Bernardin Flavien, Magierowska Magdalena, Dandekar Satya, Van Rompay Koen K A, Delwart Eric L
Blood Systems Research Institute, San Francisco, CA 94118, USA.
Virology. 2004 Apr 25;322(1):105-17. doi: 10.1016/j.virol.2004.01.022.
The total number of circulating CD4+ and CD8+ T-cells undergoing clonal expansions following SIV(mac251) infection was determined using a T-cell receptor Vbeta chain (TRBV) third complementarity-determining region (CDR3) DNA heteroduplex tracking assay (HTA). This assay measures the number of newly expanding T-cell clones but not their antigenic specificity. Fewer expanding CD4+ (3-23 per animal) than CD8+ (18-37 per animal) clonotypes were observed during the acute phase of SIV infection. CD8+ T-cell expansions peaked at 4 weeks postinfection (wpi) concomitant with early reductions in viremia. Expanding clone TRBV transcripts ranged in frequency from the limit of detection of 2% to 40% of their TRBV subfamily's transcripts. The number of expanding CD4+ or CD8+ clones correlated with neither peak, subsequent slope, nor steady-state viremia. CDR3 repertoires in CD8-expressing cells in different anatomical compartments were also analyzed. Repertoires were polyclonal in the thymus, oligoclonal in mesenteric lymph nodes, peripheral blood mononuclear cells (PBMC), and spleen, and extremely oligoclonal in intra-epithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL). The lack of correlation between the number of expanding T-cell clonotypes and viremia levels may reflect the highly variable selection pressure imposed on SIV by T-cell responses targeting different epitopes in outbred macaques.
利用T细胞受体Vβ链（TRBV）第三个互补决定区（CDR3）DNA异源双链追踪分析（HTA），确定了感染SIV（mac251）后经历克隆扩增的循环CD4⁺和CD8⁺T细胞的总数。该分析可测量新扩增的T细胞克隆数量，但无法确定其抗原特异性。在SIV感染急性期，观察到扩增的CD4⁺克隆型（每只动物3 - 23个）少于CD8⁺克隆型（每只动物18 - 37个）。CD8⁺T细胞扩增在感染后4周达到峰值，同时病毒血症早期下降。扩增克隆的TRBV转录本频率范围从检测下限的2%到其TRBV亚家族转录本的40%。扩增的CD4⁺或CD8⁺克隆数量与峰值、随后的斜率或稳态病毒血症均无相关性。还分析了不同解剖部位表达CD8的细胞中的CDR3库。胸腺中的库是多克隆的，肠系膜淋巴结、外周血单核细胞（PBMC）和脾脏中的库是寡克隆的，而上皮内淋巴细胞（IEL）和固有层淋巴细胞（LPL）中的库则是极寡克隆的。扩增的T细胞克隆型数量与病毒血症水平之间缺乏相关性，可能反映了在远交猕猴中，针对不同表位的T细胞反应对SIV施加的高度可变的选择压力。
