Fc receptors (pink; Protein Data Bank [PDB] ID 3SGJ) expressed on phagocytes can be blocked antagonistically by multivalent full-length anti-Fc receptor antibody (green and blue, bottom right; PDB ID 1HZH). However, such multivalent blockade could lead to undesired, crosslinking-induced, receptor activation. In this report, the authors developed a strategy for Fc receptor blockade without triggering unwanted receptor signaling by using a fusion protein comprising a monovalent Fc receptor-binding domain (green and blue, upper left; PDB ID 4LAR) recombinantly fused to serum albumin (yellow; PDB ID 1GNJ) as a means of half-life extension. Figure courtesy of Dr Ben Yu.