The present invention relates to improved binding proteins for use as a medicament in particular for the prevention or treatment of autoimmune and inflammatory disorders for example allergic asthma and inflammatory bowel diseases. The invention more specifically relates to a soluble protein comprising a complex of two heterodimers wherein each heterodimer essentially consists of: (i) a first single chain polypeptide comprising: (a) an antibody heavy chain sequence having VH CH1 CH2 and CH3 regions and (b) a monovalent region of a mammalian binding molecule fused to the VH region and (ii) a second single chain polypeptide comprising: (c) an antibody light chain sequence having a VL and CL region and (d) a monovalent region of a mammalian binding molecule fused to the VL region characterised in that each pair of VH and VL CDR sequences has specificity for an antigen such that the total valency of said soluble protein is six. The invention further relates to soluble SIRPa binding antibody like proteins as shown in Figure 1.
