Masp-2, a complement fixing enzyme, and uses for it

Abstract

The invention relates to the discovery and characterization of mannan binding lectin-associated serine protease-2 (MASP-2), a new serine protease that acts in the MBLectin complement fixation pathway.

1 . An isolated nucleic acid molecule capable of remaining hybridized to a nucleic acid sequence comprising SEQ ID NO:3, or to the antisense complement of a nucleic acid sequence comprising SEQ ID NO:3, under stringent wash conditions. 
     
     
         2 . An isolated nucleic acid molecule of  claim 1 , wherein said nucleic acid sequence encodes an amino acid sequence of SEQ ID NO: 1 or portions thereof, or SEQ ID NO: 2 or portions thereof. 
     
     
         3 . The isolated nucleic acid molecule of  claim 1  comprising the nucleic acid sequence of SEQ ID NO:3, or portions thereof. 
     
     
         4 . An isolated nucleic acid molecule that encodes the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2. 
     
     
         5 . The isolated nucleic acid molecule of  claim 4  that encodes the amino acid sequence of SEQ ID NO: 2. 
     
     
         6 . An expression vector comprising the nucleic acid molecule of  claim 1 . 
     
     
         7 . The expression vector of  claim 6  operably associated with a regulatory element that directs the expression of the encoded amino acid molecule. 
     
     
         8 . A host cell comprising the vector of  claim 7 . 
     
     
         9 . A method of producing recombinant MASP-2 polypeptide comprising introducing the expression vector of  claim 6  into a host cell to create a recombinant host cell, growing the recombinant host cell under conditions where MASP-2 polypeptide is expressed from said expression vector and recovering said recombinant MASP-2 polypeptide. 
     
     
         10 . An isolated recombinant polypeptide comprising an amino acid sequence at least 95% identical to SEQ ID NO: 1 or SEQ ID NO: 2. 
     
     
         11 . The isolated polypeptide of  claim 10  comprising SEQ ID NO: 1. 
     
     
         12 . The isolated polypeptide of  claim 10  comprising position 16 to position 686 of SEQ ID NO:2. 
     
     
         13 . A substantially pure recombinant polypeptide, which polypeptide comprises an amino acid sequence at least 95% identical to the sequence defined by position 16 to position 686 of SEQ ID NO:2;
 wherein said recombinant polypeptide has the following activities:
 i) cleavage of C4 and activation of the complement in an in vitro assay for MBLectin complement pathway function; and 
 ii) mannan-binding lectin (MBL) associating activity. 
   
     
     
         14 . A pharmaceutical composition comprising the polypeptide of  claim 11 . 
     
     
         15 . A pharmaceutical composition comprising the polypeptide of  claim 12  or  claim 13 . 
     
     
         16 . An isolated antibody or fragment thereof that specifically binds to a polypeptide comprising an amino acid sequence identical to SEQ ID NO: 1 or SEQ ID NO: 2. 
     
     
         17 . An antibody that specifically binds to a human mannan-binding lectin associated serine protease-2 (MASP-2). 
     
     
         18 . The antibody of  claim 16  or  17 , wherein the antibody specifically binds to a polypeptide comprising position 16 to position 686 of SEQ ID NO:2. 
     
     
         19 . The antibody of  claim 18 , wherein the antibody is a monoclonal antibody. 
     
     
         20 . The antibody of  claim 18 , wherein the antibody is a chimeric antibody. 
     
     
         21 . The antibody of  claim 18 , wherein the antibody is a single-chain antibody. 
     
     
         22 . A pharmaceutical composition comprising the antibody of  claim 16  or  17 .