Abstract: The invention relates generally to a modified human C3 protein containing a number of single amino acid changes in the ? and ?-chain of human C3 protein, designed to increase the affinity of the modified protein to factor B or Bb, to decrease the affinity of the modified protein to factor H, and to reduce the immunogenicity of the modified protein as compared to the native human C3 protein, a nucleotide sequence encoding the modified C3 protein, a plasmid or viral vector containing the nucleotide sequence for expression the modified C3 protein, and a host cell containing the plasmid or viral vector.

Abstract: The invention relates generally to derivatives of human C3 protein containing a number of single amino acid changes in the ?- and ?-chains of C3, designed to increase the affinity of the modified protein to factor B, to lessen the affinity of the modified protein for factor H, and to reduce the immunogenicity of the modified protein as compared to unmodified protein. The invention also presents methods of using these modified proteins for the treatment of certain cancers.

Abstract: The invention relates generally to a modified human C3 protein containing a number of single amino acid changes in the ? and ?-chain of human C3 protein, designed to increase the affinity of the modified protein to factor B or Bb, to decrease the affinity of the modified protein to factor H, and to reduce the immunogenicity of the modified protein as compared to the native human C3 protein, a nucleotide sequence encoding the modified C3 protein, a plasmid or viral vector containing the nucleotide sequence for expression the modified C3 protein, and a host cell containing the plasmid or viral vector.

Abstract: A modified human complement C3 protein (C3) is disclosed comprising a substitution of a portion of a human C3 protein, with a corresponding portion of a Cobra Venom Factor protein (CVF) which results in a human C3 protein with CVF functions, but with substantially reduced immunogenicity. Advantageously, the C3 protein can be manipulated to contain at least one of the following CVF functions: increased stability of the C3 convertase and increased resistance to the actions of factors H and/or I. A large number of hybrid C3 proteins containing substitutions in the C-terminal portion of the alpha chain of C3 are presented and tested for the above functions. Methods of treatment of diseases such as reperfusion injury, autoimmune diseases, and other diseases of increased complement activation are presented as well as methods of increasing the effectiveness of gene therapeutics and other therapeutics.

Abstract: The invention provides modified human complement C3 proteins, comprising a human C3 protein, wherein amino acid residues in the human C3 protein are substituted with a corresponding portion of a Cobra Venom Factor (CVF) protein, and wherein one or more amino acid residues in the CVF portion of the modified human complement C3 protein are further modified.

Abstract: A modified human complement C3 protein (C3) is disclosed comprising a substitution of a portion of a human C3 protein, with a corresponding portion of a Cobra Venom Factor protein (CVF) which results in a human C3 protein with CVF functions, but with substantially reduced immunogenicity. Advantageously, the C3 protein can be manipulated to contain at least one of the following CVF functions: increased stability of the C3 convertase and increased resistance to the actions of factors H and/or I. A large number of hybrid C3 proteins containing substitutions in the C-terminal portion of the alpha chain of C3 are presented and tested for the above functions. Methods of treatment of diseases such as reperfusion injury, autoimmune diseases, and other diseases of increased complement activation are presented as well as methods of increasing the effectiveness of gene therapeutics and other therapeutics.

Abstract: A modified human complement C3 protein (C3) is disclosed comprising a substitution of a portion of a human C3 protein, with a corresponding portion of a Cobra Venom Factor protein (CVF) which results in a human C3 protein with CVF functions, but with substantially reduced immunogenicity. Advantageously, the C3 protein can be manipulated to contain at least one of the following CVF functions: increased stability of the C3 convertase and increased resistance to the actions of factors H and/or I. A large number of hybrid C3 proteins containing substitutions in the C-terminal portion of the alpha chain of C3 are presented and tested for the above functions. Methods of treatment of diseases such as reperfusion injury, autoimmune diseases, and other diseases of increased complement activation are presented as well as methods of increasing the effectiveness of gene therapeutics and other therapeutics.

Abstract: DNA sequences encoding cobra C3, CVF1, and CVF2, as well as plasmids and transformed hosts comprising such DNA sequences, are provided.