Human complement C3 derivates with cobra venom factor-like function

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.

1 . A modified human complement C3 protein, comprising a substitution of a portion of a human C3 protein, with a corresponding portion of a Cobra Venom Factor protein of a sequence substantially related thereto. 
     
     
         2 . The modified C3 protein of  claim 1 , wherein the substituted portion of the CVF is within the alpha chain of C3. 
     
     
         3 . The modified C3 protein of  claim 2 , wherein the substituted portion of the CVF is a C-terminal portion of the alpha chain of C3. 
     
     
         4 . The modified C3 protein of  claim 3 , wherein the substituted C-terminal portion includes amino acid 1663 of the human C3 protein. 
     
     
         5 . The modified C3 protein of  claim 3 , wherein the substituted C-terminal portion is an internal portion that does not extend through the entire C-terminus of the human C3 protein. 
     
     
         6 . The modified C3 protein of  claim 1 , wherein the modified protein has substantially the same number of amino acid residues as an unmodified human C3 protein. 
     
     
         7 . The modified C3 protein of  claim 1 , wherein the substitution comprises any positions within amino acid positions 700-1663 of the human C3 protein. 
     
     
         8 . The modified C3 protein of  claim 1 , wherein the substitution comprises a first position and a last position, wherein the first position is selected from the group consisting of 749, 874, 936, ′, 1264, 1348, 1496, 1504, and 1550, and wherein the last position is selected from the group consisting of 784, 921, 970 1324, 1550, 1617, and 1663. 
     
     
         9 . The modified C3 protein of  claim 8 , wherein the substitution is selected from the group consisting of amino acids: 1550-1663, 1504-1663, 1348-1663, 1550-1617, 1504-1617, 1496-1663, 1348-1617, 1496-1617, 1264-1324, 749-784, 874-921, 994-1663, 994-1550 and 936-970. 
     
     
         10 . The modified C3 protein of  claim 1 , wherein the modified C3 protein has an affinity for factor B and supports formation of an active convertase. 
     
     
         11 . The modified C3 protein of  claim 10 , wherein the convertase has an intrinsic half-life of at least about 15 minutes at 37° C. 
     
     
         12 . The modified C3 protein of  claim 1 , wherein the modified protein has an additional 1 to 19 amino acids at the N-terminus that are not encoded by C3 or CVF. 
     
     
         13 . The modified C3 protein of  claim 1 , wherein the modified protein is substantially non-immunogenic. 
     
     
         14 . A method for depleting complement, comprising administering the modified C3 protein of  claim 1  to a patient in an amount effective for the depletion of complement. 
     
     
         15 . A method for increasing the efficiency and/or effectiveness of gene therapy, comprising: delivering the modified C3 protein of  claim 1  in an amount sufficient to deplete complement; providing the gene therapy; and observing an enhanced result therefrom. 
     
     
         16 . A method of increasing delivery of a therapeutic or diagnostic agent, comprising: delivering the modified C3 protein of  claim 1  in an amount sufficient to increase blood flow; and providing the therapeutic or diagnostic agent. 
     
     
         17 . The method of any of  claims 14 - 16 , further comprising chemically linking the modified C3 protein to an antibody with an affinity for a specific tissue prior to the delivering step. 
     
     
         18 . A method of treating a condition or disease associated with undesirable complement activation, comprising administering the modified C3 protein in an amount sufficient to deplete complement. 
     
     
         19 . The method of  claim 18 , wherein the condition or disease is selected from the group consisting of asthma, systemic lupus erythematosus, glomerulonephritis, rheumatoid arthritis, Alzheimer's disease, multiple sclerosis, myocardial ischemia, reperfusion, sepsis, hyperacute rejection, transplant rejection, cardiopulmonary bypass, myocardial infarction, angioplasty, nephritis, dermatomyositis, pemphigoid, spinal cord injury and Parkinson's disease 
     
     
         20 . A method of selecting a modified C3 protein, comprising: characterizing at least one property of the modified C3 protein to form a function profile of the modified protein; and matching the function profile with a disease or condition to be treated. 
     
     
         21 . A nucleic acid sequence encoding the modified C3 protein of  claim 1 . 
     
     
         22 . A composition comprising the modified human complement C3 protein of  claim 1  and a pharmaceutically acceptable carrier. 
     
     
         23 . A expression system expressing the modified C3 protein of  claim 1 .