Application of complement 1q for the site-selective recognition of immune complex in protein chip

Complement 1q (C1q) was applied for the specific recognition of antibody–antigen complex in antibody-based protein chip. The specific binding of C1q to antibody–antigen complex was investigated by surface plasmon resonance (SPR) with respect to Yersinia entericolitica, Salmonella typimurium, insulin, and bovine serum albumin. The protein chip was fabricated with two different kinds of antibodies a zigzag configuration. When one of antigens and fluorescein-isothiocyanate (FITC)-labeled C1q was applied on the protein chip, the specific binding event of C1q to immune complexes formed on protein chip was observed by fluorescence microscopy. These results implicate that the C1q can be used as an alternative to many antibodies that may be utilized individually on each spot of the protein chip.