Study of Oral Tolerance and Its Indirect Effects in Adoptive Cell Transfer Experiments

Parenteral exposure to antigens to which oral tolerance had been previously induced results in the inhibition of immune responses to other un- related antigens. Herein we tested whether indirect effects of oral tolerance could be adoptively transferred. Anti-Ova- and antihemoglobin-specific responsiveness as well as oral tolernace to Ova were transferred to irradiated, but not to normal, nonirradiated recepients. Irradiation, thus, facilitated adop- tive transfer of oral tolerance. However, the inhibitory (indirect) effects upon the unrelated immunogen were not adoptively transferred, even to irradiated recepients. In addition, we studied adoptively transferred CFSE-labeled spleen cells by flow cytometry in recipient spleen, inguinal lymph nodes, and bone marrow, both in irradiated and nonirradiated recipients, 1, 3, or 5 days after cell transfer. Comparing the percent and absolute number of CFSE-labeled cells in each organ displayed significant differences in the dynamics of decay of adoptively transferred cells from tolerant or immune donors.