Abstract: Antibodies against CD25 engineered with dysfunctional constant regions used to bind T regulatory cells to activate integrin to inhibit immune responses and for treatment of autoimmune diseases such as systemic lupus erythematosus, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease, in addition to transplantation rejection. The invention demonstrates that treatment of CD4+ T cells with CD25 antibody results in rapid activation of multiple integrins as measured by soluble ligand binding.