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Route of Antigen Presentation Can Determine the Selection of Foxp3-Dependent or Foxp3-Independent Dominant Immune Tolerance
Publication . Agua-Doce, Ana; Caridade, Marta; Oliveira, Vanessa G; Bergman, Lisa; Lafaille, Maria C; Lafaille, Juan J; Demengeot, Jocelyne; Graca, Luis
It has been shown that dominant tolerance, namely in transplantation, requires Foxp3+regulatory T cells. Although most tolerance-inducing regimens rely on regulatory T cells, we found that induction of tolerance to proteins in aluminum hydroxide can be achieved in Foxp3-deficient mice using nondepleting anti-CD4 Abs. This type of tolerance is Ag specific, and tolerant mice retain immune competence to respond to unrelated Ags. We demonstrated with chicken OVA-specific TCR-transgenic mice that the same tolerizing protocol (CD4 blockade) and the same target Ag (OVA) achieves Foxp3-dependent transplantation tolerance to OVA-expressing skin grafts, but Foxp3-independent tolerance when the Ag is provided as OVA-aluminum hydroxide. In the latter case, we found that tolerance induction triggered recessive mechanisms leading to elimination of effector cells and, simultaneously, a dominant mechanism associated with the emergence of an anergic and regulatory CTLA-4+IL-2lowFoxp3-T cell population, where the tolerance state is IL-10 dependent. Such Foxp3-independent mechanisms can improve the efficacy of tolerance-inducing protocols.
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Fundação para a Ciência e a Tecnologia
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3599-PPCDT
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HMSP-ICT/0034/2013