Cytoprotection of human umbilical vein endothelial cells against apoptosisand CTL-mediated lysis provided by caspase-resistant Bcl-2 without alterations in growth or activation responses

Graft endothelial cells are primary targets of host CTL-mediated injury in acute allograft rejection. As an in vitro trial of gene therapy to reduce C TL-mediated endothelial injury,,ve stably transduced early passage HUVEC wi th a caspase-resistant mutant form (D34A) of the anti-apoptotic gene Bcl-2, Bcl-2 transductants were compared with HUVEC transduced in parallel with a n enhanced green fluorescent protein (EGFP) gene. Both transduced HUVEC hav e equivalent growth rates in complete medium and both show contact inhibiti on of growth. However, compared with EGFP-transduced HUVEC, the Bcl-2-trans duced cells are resistant to the apoptotic effects of serum and growth fact or withdrawal and are also resistant to the induction of apoptosis by staur osporine or by ceramide, with or without TNF. Transduced Bcl-2 did not redu ce TNF-mediated NF-KB activation or constitutive expression of class I MHC molecules. HUVEC expressing D34A Bcl-2 mere significantly more resistant to lysis by either class I-restricted alloreactive or PHA-redirected CTL than were HUVEC expressing EGFP. We conclude that transduction of graft endothe lial cells,vith D34A Bcl-2 is a possible approach for reducing allograft re jection.