Chemical linked Fabs’ is type of bispecific antibody formed by two chemically linked Fabs (fragments antigen-binding). These two Fab fragments are fromed by two different monoclonal antibodies and are linked by chemical linker such as a thioether. Typically, one of the Fabs binds to a tumour antigen (such as CD30) and the other to a protein on the surface of an immune cell, an Fc receptor on a macrophage, for instance. In this way, tumour cells are attached to immune cells, leading to their destruction. The figure shows an example of chemically linked Fabs: two Fab fragments are linked with a thioether, resulting in a F(ab’)₂. The molecule is bound to a tumour cell via the tumour antigen CD30 and to a macrophage via an Fc receptor.