Da tolerância oral e seus efeitos indiretos na transferência adotiva singênica e na rejeição de aloenxertos

Abstract

Oral tolerance is characterized by a reduction in specific immunological activities to a protein previously given by oral route. Parenteral exposure to antigens to which oral tolerance had been previously induced affects (inhibits) immunological activities connected to unrelated antigens, a phenomenon we have called indirect effects of oral tolerance. Herein, we investigated the possibility of adoptively transferring oral tolerance and its indirect effects to immunocompetent syngeneic recipients by the transfusion of spleen cells and serum from tolerant donors. We also investigated if the indirect effects of oral tolerance interfere in the rejection of allografts. The adoptive transfer of oral tolerance and its indirect effects is more easily demonstrated when we evaluated DTH reaction in C57BL/6 and BALB/c recipient mice. BALB/c mice are more susceptible to the adoptive transfer of these phenomena when we evaluate specific antibody production. In recipients with an intact immune system, there is a barrier (syngeneic barrier) that impairs the functional implantation of transferred cells, interfering with their specific immunological activities. However, the transfer of different immune system components is able to bypass this barrier, demonstrating the importance of interactions between molecular and cellular components to the establishment of the phenomena studied herein. The indirect effects of oral tolerance seem to delay the rejection of skin allografts, demonstrating its systemic character. Phenomena such as the syngeneic barrier and the indirect effects of oral tolerance will better understood in models that describe the interdependence among the components of the immune system.