9167
A chimeric TCR gene , comprising an anti-hapten single-chain Ab variable fragment fused to the transmembrane and cytoplasmic regions of the human TCR zeta-chain , was used to determine whether the tetracycline-regulatable system could be used to regulate gene expression in T cells .
 anti-hapten single-chain Ab variable fragment, chimeric TCR gene, T cells, transmembrane and cytoplasmic regions, human TCR zeta-chain
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 anti-hapten single-chain Ab variable fragment, chimeric TCR gene, T cells, transmembrane and cytoplasmic regions, human TCR zeta-chain