The present disclosure provides antibody sequences found in antibodies that bind to human CD25, in particular an anti CD25-a- 646 antibody which do not block the binding of CD25 to IL-2 or IL-2 signalling. The claimed antibody binds to the epitope : PHATFKAMA YKEGTM (42-56) 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.