Role of selectin-dependent adhesion in cardiac allograft rejection

Selectins play important roles in the inflammatory responses by eliciting leukocyte rolling. The roles of E- and P-selectins in the acute rejection of cardiac allografts remain unclear. This study was designed to evaluate whether E- and P-selectins participate in the pathophysiology of heart rejection.

Heterotopic heart transplantation was performed in both mice and rats in full histoincompatibility combinations. Immunohistochemistry, flow-cytometry, and reverse transcriptase- polymerase chain reaction were performed to evaluate E-, P-selectin and sialyl Lewis X (SLeX) expression in rejecting cardiac allografts. The effects of short-term administration of monoclonal antibodies (mAbs) to E- and P-selectins on cardiac allograft survival were also evaluated.

Significant prolongation of graft survival was observed in mice treated with either anti-E- or P-selectin mAbs, or both. The enhanced endothelial and mRNA expression of E- and P-selectins was observed in the rejecting cardiac allografts. Some graft- infiltrating mononuclear cells were double-stained with both anti-SLeX and anti-alphabetaT cell receptor mAbs. Flow-cytometric analysis of graft-infiltrating cells also showed enhanced SLeX expression.

These results suggest that both P- and E-selectins are critically involved in the early development of acute heart rejection.