ARS | Publication request: Genomic expression analysis of quiescent CD8 cells from tumor-infiltrating lymphocytes of in vivo liver tumor by single-cell mRNA differential display

Submitted to: Nature Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2008
Publication Date: N/A

Interpretive Summary: The quiescent state of T lymphocytes was thought to be due to the lack of activation signals. However, recent studies indicated that quiescence in CD8 T cells was an actively maintained state rather than a defective state resulting from the absence of the stimulation signals. The molecular mechanisms underlying the quiescent status in CD8 T cell of TIL remains unclear due to the technological limitation of analyzing the small number of T cells within cancer tissues. Here we describe a genomic approach combining single-cell mRNA differential display and RNA subtractive hybridization to elucidate the mechanism of the CD8 T-cell ignorance. By comparing the quiescent CD8 T-cell obtained from liver tumor TIL with a reference control at the single cell level, we identified candidate genes for differential expression profile by high throughput screening and comparative analysis of expressed sequence tags (ESTs). While T-cell receptor, TNF receptor, TRAIL and perforin are down-regulated, several key genes (such as Tob, TGF-beta, LKLF, SnoA, Ski, Myc, ERF and REST/NRSF complex) are highly expressed in the quiescent CD8 cells. Tob and TGF-' expression are significantly decreased after reactivating the quiescent T cells by IL-2. Real time PCR further confirmed these expression profiles. Based on these data, a regulation model of CD8 T-cell quiescence is proposed including three pathways, which are up-regulation of TGF-beta pathway, shift of myc web and inhibition of cell cycle. These results will set up a good basis to study the mechanism of CD8 cell ignorance.

Technical Abstract: We performed a genomic approach combining single-cell mRNA differential display and RNA subtractive hybridization to elucidate the CD8 T-cell ignorance. By comparing the quiescent CD8 T-cell obtained from liver tumor TIL with a control at the single cell level, we identified candidate genes differentially expressed by high-throughput screening and comparative analysis of expressed sequence tags (ESTs). While T-cell receptor, TNF receptor, TRAIL and perforin are down-regulated, key genes like Tob, TGF-beta, LKLF, SnoA, Ski, Myc, ERF and REST/NRSF complex are highly expressed in the quiescent CD8 cells. Real time PCR further confirmed these results. A regulation model of CD8 T-cell quiescence is proposed including three ways: up-regulation of TGF-beta pathway, shift of myc web and inhibition of cell cycle.