.jpg "Vincent G. Geenen, MD, PhD, Professor emeritus photo")
Res Prof/Head emeritus
University Hospital of Liege
Liege-Sart Tilman, Belgium
Vincent GEENEN, Research Director emeritus of Belgian FSR and Professor emeritus at the University of Liège
Member of the Royal Academy of Medicine of Belgium
University Hospital of Liège, GIGA Research Institute and Division of Endocrinology, 4000 Liège, Belgium
Vincent Geenen initiated his scientific career by developing a specific radioimmunoassay of oxytocin with an application to the quantification of oxytoxin produced by bovine luteinizing granulosa cells in culture. Howver, oxytocin secretion was not observed with human luteinizing granulosa cells. According to an ancient report (Ott and Scott, 1910) showing that extracts of thymus stimulates milk ejection after injection into the goat, Vincent Geenen and colleagues reported in Science (1982) that oxytocin and equimolar contents of neurophysin are detected in the human thymus. Further studies identified neurokinin A, neurotensin, and IGF-2 as the dominant members of their related families expressed in thymic epithelial cells (TECs). Further studies have shown that these neuroendocrine precursors are not linked to (neuro)secretion but are processed for presentation by the major histocompatibility complex (MHC) expressed by TECs to intrathymic developing T cells. This presentation promotes negative selection of self-reactive T cells, as well as the generation of self-specific regulatory T cells. A thymus dysfunction in this process is responsible for the development of an autoimmune response oriented against these neuroendocine principles. This condition is necessary but not sufficient to determine neuroendocrine autoimmunity and environmental factors are also required. Our studies have evidenced a biochemical difference between neuroendocrine tolerogenic self-antigens and immunogenic auto-antigens. This difference could be further exploited for the achievement of "inverse negative self-vaccines" against autoimmune diseases.
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