A process that directly activates any of the steps required for tolerance, a physiologic state in which the immune system does not react destructively against the components of an organism that harbors it or against antigens that are introduced to it. [ https://www.worldcat.org/search?q=bn%3A0781735149 GOC:jal http://purl.obolibrary.org/obo/go/references/0000022 ]