Potencial das toxinas recombinantes Potencial das toxinas recombinantes do veneno de aranha marrom como ferramentas na indução de tolerância oral e imunomodulaçãodo veneno de aranha marrom como ferramentas na indução de tolerância oral e imunomodulação

Abstract

Oral tolerance refers to physiologic induction of immunosuppression that occurs in mucosal induced by oral administration of an antigen. This method has been used to induce reduction of humoral and cellular responses involved in autoimmune diseases, allergies and may be an alternative to reduce transplant rejection. We investigated potential of dermonecrotic recombinant toxins of brown spider Loxosceles intermedia specie to induce a state of mucosal tolerance in a animal model. We did this by assessing the cellular mechanisms involved and the immune response of tolerant animals against specific and nonspecific immune stimulation. Dermonecrotic toxin LiRecDT1 and its mutated form, LiRecDT1 H12A (with residual dermonecrotic activity), has been used. Mice were treated with recombinant toxins, orally, for 21 days, with a total of 90g per animal. After oral tolerance protocol, mesenteric lymph nodes were processed for western blotting and the expression of nuclear transcription factor Foxp3 and cytokine Tgf-β were analyzed. LiRecDT1 and LiRecDT1 H12A tolerant groups showed an increase in expression of both proteins, which could be related to a increase in regulatory T-cells population. Adoptive transfer of splenocytes to naive mice from LiRecDT1 H12A tolerated group induced paw edema reduction, with supports this theory (adoptive transfer). Our results also demonstrated a bystander tolerance when LiRecDT1 H12A tolerated mice showed a decrease in IgG production and paw edema induction by Polybia paulista wasp venom. LiRecDT1 H12A tolerance also showed an apparent reduction in skin allograft rejection using C57BL/6 mice as donor and tolerated Swiss mice as receptor. Considering the results we concluded that oral tolerance induced by LiRecDT1 and LiRecDT1 H12A toxins could be involve increase in Tregs and non-inflammatory cytokines, and LiRecDT1 H12A tolerance can reduce specific and non specific immunology responses and allografts transplants rejection.