NTB-A, a surface molecule involved in natural killer cells activity

Abstract

The present invention relates to a novel protein, termed NTB-A, nucleic acid molecules encoding the same and uses thereof. The invention also relates to methods of regulating Natural Killer cells activity by regulating the activity of NTB-A in vitro, ex vivo or in vivo. The invention also comprises methods of screening active compounds using NTB-A or fragments thereof, or nucleic acid encoding the same, or recombinant host cells expressing said polypeptide.

1 . A composition of matter comprising: 
 a) an isolated nucleic acid molecule, wherein said nucleic acid molecule is selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;  
 ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);  
 iii) a complementary strand of a nucleic acid molecule of i) or ii);  
 iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;  
 v) a nucleic acid molecule that encodes a human NTB-A protein; or  
 vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides;  
   b) a nucleic acid probe, wherein said probe is complementary and specifically hybridizes to a nucleic acid molecule selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;  
 ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);  
 iii) a complementary strand of a nucleic acid molecule of i) or ii);  
 iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;  
 v) a nucleic acid molecule that encodes a human NTB-A protein; or  
 vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides;  
   c) a pair of nucleic acid primers, wherein at least one primer of said pair is complementary and specifically hybridizes to a nucleic acid molecule selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;  
 ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);  
 iii) a complementary strand of a nucleic acid molecule of i) or ii);  
 iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;  
 v) a nucleic acid molecule that encodes a human NTB-A protein; or  
 vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides;  
   d) a vector comprising a nucleic acid molecule selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;  
 ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);  
 iii) a complementary strand of a nucleic acid molecule of i) or ii);  
 iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;  
 v) a nucleic acid molecule that encodes a human NTB-A protein; or  
 vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides;  
   e) a host cell comprising a vector, said vector comprising a nucleic acid molecule selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;  
 ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);  
 iii) a complementary strand of a nucleic acid molecule of i) or ii);  
 iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;  
 v) a nucleic acid molecule that encodes a human NTB-A protein; or  
 vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides;  
   f) an isolated polypeptide comprising: 
 i) an amino acid sequence encoded by a nucleic acid molecule according to a);  
 ii) SEQ ID NO:2; or  
 iii) at least 5 contiguous amino acid residues of SEQ ID NO:2;  
   g) an isolated antibody that specifically binds to a polypeptide comprising: 
 i) an amino acid sequence encoded by a nucleic acid molecule according to a);  
 ii) SEQ ID NO:2; or  
 iii) at least 5 contiguous amino acid residues of SEQ ID NO:2; or  
   h) a pharmaceutical composition comprising a compound that regulates the activity of NTB-A and a pharmaceutically acceptable vehicle or carrier.    
     
     
         2 . The composition of matter according to  claim 1 , wherein said composition of matter is a nucleic acid molecule that comprises a sequence encoding a polypeptide comprising SEQ ID NO:2 or a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2.  
     
     
         3 . The composition of matter according to  claim 1 , wherein said composition of matter is a pharmaceutical composition comprising a compound that regulates the activity of NTB-A and a pharmaceutically acceptable vehicle or carrier that further comprises a compound that regulates a 2B4 receptor.  
     
     
         4 . The composition of matter according to  claim 3 , wherein the compound that regulates the activity of NTB-A comprises an antibody that inhibits or reduces NTB-A activity and the compound that regulates a 2B4 receptor is an antibody that inhibits or reduces 2B4 activity.  
     
     
         5 . A method of using a composition of matter according to  claim 1  for: 
 a) the preparation of cells expressing a polypeptide;    b) preparing an antibody;    c) selecting, screening or characterizing a compound;    d) regulating the immune function of a patient; or    e) detecting a dysfunction in a subject or determining the risk of a subject developing a dysfunction.    
     
     
         6 . The method according to  claim 5 , wherein said method is a method of preparing cells expressing a polypeptide, said method comprising introducing a nucleic acid molecule or vector into cells in vitro and selecting the cells which express the polypeptide or progeny of said cells, wherein said nucleic acid molecule or vector is: 
 a) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;    b) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid of a);    c) a complementary strand of a nucleic acid molecule of a) or b);    d) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;    e) a nucleic acid molecule that encodes a human NTB-A protein;    f) a fragment of a nucleic acid molecule of a), b), c), d) or e), said fragment comprising at least 9 contiguous nucleotides; or    g) a vector comprising a nucleic acid molecule of a), b), c), d), e) or f).    
     
     
         7 . The method according to  claim 5 , wherein said method is a method of preparing an antibody, said method comprising injecting to a non-human mammal a polypeptide comprising SEQ ID NO:2 or a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2 and collecting the antibody, serum or antibody-producing cells in said mammal.  
     
     
         8 . The method according to  claim 5 , wherein said method is a method of selecting, screening or characterizing a compound, said method comprising contacting a test compound with a polypeptide comprising SEQ ID NO:2 or a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2 and determining the ability of said test compound to bind to said polypeptide.  
     
     
         9 . The method according to  claim 5 , wherein said method is a method of selecting, screening or characterizing a compound, said method comprising contacting a test compound with a host cell and determining the ability of said test compound to bind to said polypeptide, wherein said host cell comprises a vector, said vector comprising a nucleic acid molecule selected from: 
 i) a nucleic acid encoding a polypeptide comprising SEQ ID NO:2;    ii) a nucleic acid which hybridizes to the nucleic acid of a) or to a portion thereof, said portion comprising at least 30 contiguous nucleotides of a nucleic acid i);    iii) a complementary strand of a nucleic acid molecule of i) or ii);    iv) a nucleic acid molecule encoding a polypeptide comprising at least 5 contiguous amino acid residues of SEQ ID NO:2;    v) a nucleic acid molecule that encodes a human NTB-A protein; or    vi) a fragment of a nucleic acid molecule of i), ii), iii), iv) or v), said fragment comprising at least 9 contiguous nucleotides.    
     
     
         10 . The method according to  claim 5 , wherein said method is a method of selecting, screening or characterizing a compound, said method comprising contacting a test compound with a NK cell in the presence of an antibody specific for NTB-A and determining the activity of said test compound by measuring the cytolytic activity of said NK cells.  
     
     
         11 . The method according to  claim 5 , wherein said method is a method of selecting, screening or characterizing a compound, said method comprising contacting a test compound with a NTB-A polypeptide in the presence of a binding partner thereof and assessing the capacity of said test compound to modulate the interaction between said NTB-A polypeptide and said binding partner.  
     
     
         12 . The method according to  claim 5 , wherein said method is a method of selecting, screening or characterizing a compound, said method comprising (i) determining the ability of a test compound to bind to a NTB-A polypeptide and (ii) determining the ability of a test compound selected in (i) to regulate NK cell-mediated target cell lysis.  
     
     
         13 . The method according to  claim 5 , wherein said method is a method of regulating the immune function in a subject comprising the administration of a compound that regulates the activity of a NTB-A polypeptide to a subject.  
     
     
         14 . The method according to  claim 13 , wherein the compound regulates the activity of NK cells in a subject.  
     
     
         15 . The method according to  claim 5 , wherein said method is a method of detecting a dysfunction in a subject or the risk of a subject developing a dysfunction comprising determining, in a sample derived from said subject, the presence of a mutation or alteration in NTD-A gene or RNA, or determining the presence or amount of a NTB-A polypeptide.