Polypeptides having a triggering nk activity and biological applications

Abstract

The invention relates to polypeptides having a triggering NK activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide having SEQ ID NO: 1, and any immunogenic fragments thereof, as well as to the polyclonal and monoclonal antibodies directed against said polypeptides, and immuno-reactive fragments thereof. Application for detecting NK cells in a sample, for their removal from a sample or for enrichment of NK cells, and for NK cell natural cytotoxicity regulation.

1 . A composition of matter comprising:
 a) an isolated nucleic acid encoding a polypeptide that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   b) an isolated nucleic acid encoding the polypeptide of SEQ ID NO: 1 or an isolated nucleic acid comprising SEQ ID NO: 2;   c) an isolated polyclonal antibody that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   d) an isolated monoclonal antibody, or an immunoreactive fragment thereof, that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   e) a hybridoma producing a monoclonal antibody, or an immunoreactive fragment thereof, that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   f) a polyclonal or monoclonal antibody, coupled to a first marker, that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof and an anti-CD3 antibody coupled to a second marker, said polyclonal or monoclonal antibody and said anti-CD3 antibody being provided in a kit for the detection of NK cells;   g) a pharmaceutically acceptable excipient and a polyclonal or monoclonal antibody that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   h) a pharmaceutically acceptable excipient and an immunoreactive fragment of an antibody that binds a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1, or an immunogenic fragment thereof;   i) a vector comprising an nucleic acid sequence encoding an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1;   j) a vector comprising an nucleic acid sequence encoding SEQ ID NO: 1 or a vector comprising the nucleic acid of SEQ ID NO: 2; or   k) a transformed host cell comprising: i) a vector comprising an nucleic acid sequence encoding an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1; ii) a vector comprising an nucleic acid sequence encoding the polypeptide of SEQ ID NO: 1; or iii) a vector comprising the nucleic acid of SEQ ID NO: 2.   
     
     
         2 . The composition of matter according to  claim 1 , wherein said isolated monoclonal antibody is reactive with NK cells expressing CD56 molecules and a minor subset of CD3T cells. 
     
     
         3 . The composition of matter according to  claim 1 , wherein said polyclonal or monoclonal antibody induces cytotoxicity in a redirected killing assay. 
     
     
         4 . The composition of matter according to  claim 1 , wherein the immunoreactive fragment of said monoclonal antibody inhibits NK cell cytotoxicity in NKp80-sensitive target cells. 
     
     
         5 . The composition of matter according to  claim 1 , wherein said polyclonal or monoclonal antibody is fixed on a solid support. 
     
     
         6 . The composition of matter according to  claim 1 , wherein said polyclonal or monoclonal antibody is coupled to a marker. 
     
     
         7 . The composition of matter according to  claim 1 , wherein said monoclonal antibody or immunoreactive fragment is humanized. 
     
     
         8 . A method for screening molecules having a triggering or an inhibitory NK cell or T cell sub-population activity comprising a transfectant expressing a polypeptide that has a NK cell triggering activity and an amino acid sequence that is at least 80% identical over its entire length to the polypeptide of SEQ ID NO: 1 or that comprises SEQ ID NO: 1 with a molecule and selecting those molecules that significantly modify the NKp80-mediated signals in the transfectant as compared to a non-transfected control.