Target-cell restricted, costimulatory, bispecific and bivalent anti-cd28 antibodies

A method for treatment of a disease in a subject, comprising administering a binding molecule which is at least bispecific comprising at least two first antigen binding sites and at least one second antigen binding site, wherein

• (i) the at least two first antigen binding sites are capable of specifically binding to an epitope of T-cell-specific surface glycoprotein CD28 and wherein each are provided as an antigen binding fragment of an antibody and which is not a Fab, F(ab′)2 or IgG;
• and
• (ii) the at least one second antigen binding site is capable of binding to an epitope of an antigenic target protein expressed on or in a cell associated with the disease in the subject and wherein the at least one second antigen binding site(s) is derived from an antibody or antibody like molecule and comprises a Fab, F(ab′)2 or IgG.