PMID: 9190915Jun 15, 1997Paper

Overexpression of the heat shock protein 70 enhances the TCR/CD3- and Fas/Apo-1/CD95-mediated apoptotic cell death in Jurkat T cells

The Journal of Immunology : Official Journal of the American Association of Immunologists
S N LiossisG C Tsokos

Abstract

To investigate whether the protective effects of the 70-kDa heat shock protein (hsp70) extend to the apoptotic mode of cell death, we transfected Jurkat T cells with the gene for the human hsp70 and challenged the cells with an anti-Fas mAb or with two different murine anti-CD3 mAbs. The anti-Fas mAb-triggered apoptotic cell death and the anti-CD3 mAb-mediated activation-induced cell death were significantly enhanced in the gene-transfected Jurkat cells overexpressing hsp70 compared with the unmanipulated and the vector-transfected cells. On the other hand, the well-established protective effect that this protein offers to the cells was unaffected, as determined by enhanced viability of gene-transfected cells exposed to a lethal heat shock. To investigate the mechanisms that are responsible for the increased susceptibility of the gene-transfected cells to apoptotic death, we studied the TCR/CD3-initiated events that showed a significant down-regulation of the protein tyrosine phosphorylation levels and the cytoplasmic free Ca2+ responses. As for the Fas/Apo-1/CD95-mediated early events, the activity of protein serine/threonine phosphatases was markedly increased in the cells overexpressing hsp70. Our study demonstrates that hsp...Continue Reading

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