The presently described technology relates to the modulation of specific immune responses to create a protective immunity in the treatment of autoimmune diseases and diseases requiring the transplantation of tissue. In particular, the present technology relates to the suppression of immune responses in a targeted fashion, by increasing the functional concentration of the CEACAM1 protein in a target tissue to create a localized protective immunity for the treatment of autoimmune diseases and diseases requiring the transplantation of tissue.