Chitinase chitin-binding fragments

Abstract

The present invention provides chitin-binding fragments of human chitinase, fragment analogs, purified and isolated polynucleotide sequences encoding such fragments and analogs, and materials and methods for the recombinant production of human chitinase fragment products which are expected to be useful as in products for detecting chitin, binding chitin, and treating fungal infections or for development of products useful for treating the same.

What is claimed is:  
     
         1 . A chitin-binding, chitinase-inactive polypeptide comprising a chitin-binding fragment of the 54 C-terminal amino acids of human chitinase as set forth in SEQ ID NO: 2.  
     
     
         2 . The polypeptide of  claim 1  selected from the group consisting of a polypeptide having the sequence of amino acid residues 347 through 445 of SEQ ID NO: 2, polypeptide having the sequence of amino acid residues 374 through 445 of SEQ ID NO: 2, a polypeptide having the sequence of amino acid residues 392 through 445 of SEQ ID NO: 2, a polypeptide having the sequence of amino acid residues 395 through 445 of SEQ ID NO: 2, and a polypeptide having the sequence of amino acid residues 397 through 445 of SEQ ID NO: 2.  
     
     
         3 . A polypeptide selected from the group consisting of polypeptides having the sequence of amino acid residues X through Y of SEQ ID NO: 2, wherein X is a consecutive integer from 347 through 397 and Y is 445.  
     
     
         4 . A chitin-binding, chitinase-inactive polypeptide comprising a polypeptide of  claim 3 .  
     
     
         5 . A fusion protein comprising the polypeptide of  claim 1  fused to a heterologous polypeptide.  
     
     
         6 . The fusion protein of  claim 5  wherein the heterologous polypeptide is an enzyme.  
     
     
         7 . A composition comprising the polypeptide of  claim 1  and a physiologically acceptable diluent.  
     
     
         8 . The composition of  claim 7  further comprising a non-chitinase anti-fungal agent.  
     
     
         9 . A composition comprising the polypeptide of  claim 1  or  4  conjugated to an anti-fungal agent.  
     
     
         10 . A method of treating fungal infection comprising the step of administering to a subject suffering from fungal infection a composition according to any one of claims  7  through  9 .  
     
     
         11 . The method of  claim 10  further comprising the step of administering to said subject a non-chitinase anti-fungal agent.  
     
     
         12 . A composition comprising the polypeptide of  claim 1  or  4  conjugated to a detectable label.  
     
     
         13 . The composition of  claim 12  wherein the detectable label is selected from the group consisting of radioisotopes, fluorophores, dyes, electron-dense compounds and enzymes.  
     
     
         14 . A method for determining the presence of chitin in a sample comprising the steps of: 
 (a) contacting the sample with the composition of  claim 12  and    (b) determining the amount of labelled polypeptide bound to chitin.    
     
     
         15 . A kit for diagnosing the presence of chitin in a sample comprising the composition of  claim 12 .  
     
     
         16 . A purified, isolated polynucleotide encoding the polypeptide of  claim 1 .  
     
     
         17 . The polynucleotide of  claim 16  that is DNA.  
     
     
         18 . A vector comprising the DNA of  claim 17 .  
     
     
         19 . A host cell stably transformed or transfected with the DNA of  claim 17  in a manner allowing the expression in said host cell of a polypeptide encoded by said DNA.  
     
     
         20 . A method for producing a polypeptide comprising a human chitinase fragment comprising culturing the host cell of  claim 19  in a nutrient medium and isolating said polypeptide from said host cell or said nutrient medium.  
     
     
         21 . A purified, isolated polypeptide produced by the method of  claim 20 .  
     
     
         22 . A monoclonal antibody that specifically binds to an epitope within the 54 C-terminal amino acids of human chitinase as set forth in SEQ ID NO: 2.  
     
     
         23 . The monoclonal antibody of  claim 22  that competes with monoclonal antibody 243Q, produced by the hybridoma deposited under ATCC Accession No. ______, for binding to a chitin-binding, chitinase-inactive fragment of human chitinase.  
     
     
         24 . The monoclonal antibody of  claim 22  that competes with monoclonal antibody 243M, produced by the hybridoma deposited under ATCC Accession No. ______, for binding to a chitin-binding, chitinase-inactive fragment of human chitinase.