Abstract: Aspects of the present invention relate to the detection of binding events associated with a protein complex comprised of a protease deficient Complement Factor I (FI) protein. Certain embodiments of the present invention provide for a protein complex comprising a Complement Factor I, C3b and further comprising at least one other protein from Complement Factor H (FH), Factor-H-like protein 1 (FHL-1), soluble membrane cofactor protein (sMCP), and soluble complement receptor 1 (sCR1), wherein the Complement Factor I comprises at least one mutation that causes inactivation of Complement Factor I protease activity.

Abstract: Aspects of the present invention relate to the recombinant production of a mature complement system protein. Certain embodiments of the present invention relate to recombinant production of fully mature human complement Factor I protein (CFI). Included herein are details of an expression vector with which to recombinantly express fully mature human CFI from mammalian cells. Further disclosed are chromatography steps with which to purify recombinantly expressed CFI. Certain aspects of the present invention relate to the use of an expression system in gene therapy and the like. Certain embodiments of the present invention relate to use of said vector as a medicament, for example for use in the treatment of complement-mediated disorders.

Abstract: The disclosure provides, in part, compositions comprising mature recombinant mature Complement Factor I (CFI) protein and methods of making and using those compositions.