The 20S proteasome core, active within apoptotic exosome-like vesicles, induces autoantibody production and accelerates rejection

Autoantibodies to components of apoptotic cells, such as anti-perlecan antibodies, contribute to rejection in organ transplant recipients. However, mechanisms of immunization to apoptotic components remain largely uncharacterized. We used large-scale proteomics, with validation by electron microscopy and biochemical methods, to compare the protein profiles of apoptotic bodies and apoptotic exosome-like vesicles, smaller extracellular vesicles released by endothelial cells downstream of caspase-3 activation. We identified apoptotic exosome-like vesicles as a central trigger for production of anti-perlecan antibodies and acceleration of rejection. Unlike apoptotic bodies, apoptotic exosome-like vesicles triggered the production of anti-perlecan antibodies in naïve mice and enhanced anti-perlecan antibody production and allograft inflammation in mice transplanted with an MHC (major histocompatibility complex)–incompatible aortic graft. The 20S proteasome core was active within apoptotic exosome-like vesicles and controlled their immunogenic activity. Finally, we showed that proteasome activity in circulating exosome-like vesicles increased after vascular injury in mice. These findings open new avenues for predicting and controlling maladaptive humoral responses to apoptotic cell components that enhance the risk of rejection after transplantation

6 Propositions : Luc Béland, Lucio de Heusch, Christian Kiopini, Chris Knudsen, Richard Mill, Leopold Plotek

In an introductory text, Thériault notes the rise of pluralism in Québec visual arts. Gauthier contextualizes works selected by six Québec artists for the exhibition. Statements by the artists. Biographical notes. 1 bibl. ref

Les perspectives professionnelles au Québec, 1985-1993 : modèle québécois de prévision par profession (MQPP) /

Notes (part. bibliogr.) au bas des p

New Directions : Toronto/Montréal

Grünwald and Nemiroff discuss the strategies of image-making adopted by 14 contemporary artists whose work represents a return to the figure. Artists' statements. Biographical notes