C4B and viral infectious disease: Specific genes with documented roles in host defense against influenza and other viral infections that were downregulated in AMØs include Ripk3 (30), Msr1 (31), Cxcl17 (32), C1q (33), C4a (34), C4b (35), Cfh (36), Ch25h (37), Ccl17 (38), Cd200 (39), Gbp6 (40), Iigp1 (41), Pyhin1 (42), and the IFN-stimulated antiviral effector Oasl2 (43).