Role of platelet-activating factor in functional alterations induced by xenoreactive antibodies in porcine endothelial cells

Luigi Biancone, Vincenzo Cantaluppi, Giuseppe Segoloni, Mariarosaria Boccellino, Lorenzo Del Sorbo, Pier Giulio Conaldi, Larry W. Tjoelker, Shoici Maruyama, Edward Cantu, David Stern, Giuseppe Andres, Giovanni Camussi

Research output: Contribution to journalArticlepeer-review

Abstract

Background. Platelet-activating factor (PAF) is a phospholipid mediator of inflammation which has been implicated in rejection. The interaction of anti-α-galactosyl natural antibodies (anti-α gal Abs) with endothelial cells is the initial step for the development of xenograft rejection. In our study, we stimulated porcine aorthic endothelial cells (PAEC) with anti-α gal IgG to investigate the synthesis of PAF from PAEC and its biological consequences. Methods and Results. PAF was extracted and chromatografically purified from cultured PAEC stimulated with baboon anti-α gal Abs. The Abs induced a dose-dependent synthesis of PAF peaking after 39 min of incubation, and decreasing thereafter. Concomitant cell shape change, motility, and cytoskeleton redistribution were observed. These events were prevented by addition of a panel of PAF-receptor antagonists. An SV40 T-large antigen-immortalized PAEC line was engineered to express PAF acetyl-hydrolase (PAF-AH) cDNA, the major PAF-inactivating enzyme. These transfected cells exposed to anti-α gal Abs showed reduced cell contraction and motility compared with empty vector-transfected cells. Moreover, in PAEC stimulated with anti-α gal Abs, the synthesis of PAF promoted the adhesion of a monocytic cell line as shown by the inhibitory effect of PAF-receptor antagonists and of PAF-AH expression. Finally, studies on cell monolayer demonstrated an enhanced permeability 48 hr after exposure to anti-α gal Abs, and this increase was prevented by PAF-inactivation and by PAF-receptor blockade. Conclusions. These results demonstrate that on stimulation with anti-α gal Abs, PAEC synthetize PAF which can contribute to several vascular events involved in xenograft rejection.

Original languageEnglish
Pages (from-to)1198-1205
Number of pages8
JournalTransplantation
Volume70
Issue number8
Publication statusPublished - Oct 27 2000

ASJC Scopus subject areas

  • Transplantation
  • Immunology

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