FH and infection: Chimeric proteins that fuse pathogen binding domains of either FH (CCPs 6–7) of the Fc region of human IgG (FH6–7/IgG) or C4BP (CCPs 1–2) fused to the constant domains CH2, CH3, and CH4 of IgM (C4BP1–2/IgM) resulting in a hexavalent chimeric protein have been developed as alternative strategies to control infection (18, 19).