The present disclosure provides antibody sequences found in antibodies that bind to human CD25, in particular an anti CD25- a-686 antibody which do not block the binding of CD25 to IL-2 or IL-2 signalling. The claimed antibody binds to the epitopes: NSSHSSWDNQCQCTS (70 to 84) on CD25 Antibodies and antigen- binding portions thereof including such sequences can be used in pharmaceutical compositions and methods of treatment, in particular for treating cancer.