Mammalian cell surface antigens; related reagents

Abstract

Purified genes encoding a T cell surface antigen from a mammal, reagents related thereto including purified proteins, specific antibodies, and nucleic acids encoding this antigen are provided. Methods of using said reagents and diagnostic kits are also provided.

What is claimed is: 
     
         1 . A substantially pure or recombinant 312C2 protein or conservatively modified variants thereof, said protein:
 a) is expressed on activated T cells; or   b) specifically binds to antibodies generated against SEQ ID NO: 2 or 4.   
     
     
         2 . A protein or peptide of  claim 1 , selected from the group consisting of:
 a) a natural protein from a warm blooded animal selected from the group of birds and mammals, including a rodent or primate;   b) a protein or peptide:
 i) comprising at least one polypeptide segment of at least 14 amino acids of SEQ ID NO: 2; 
 ii) comprising at least one polypeptide segment of at least 14 amino acids of SEQ ID NO: 4; or 
 iii) which is not glycosylated; 
 iv) which is in a buffered solution; 
 v) which is attached to a solid substrate; 
 vi) which exhibits a plurality of epitopes from SEQ ID NO: 2 or 4; 
 vii) which is detectably labeled; 
 viii) which is a synthetic polypeptide; 
 ix) which is conjugated to a chemical moiety; 
 x) which is a 5-fold or less substitution from a natural sequence; or 
 xi) which is a deletion or insertion variant from a natural sequence. 
   
     
     
         3 . A protein or peptide of  claim 1 , comprising a sequence from the extracellular or the intracellular portion of a 312C2. 
     
     
         4 . A fusion protein comprising a peptide of  claim 1 . 
     
     
         5 . A sterile composition comprising the protein of  claim 1 , and a pharmaceutically acceptable carrier. 
     
     
         6 . An antibody which specifically binds a protein or peptide of  claim 1 . 
     
     
         7 . An antibody of  claim 6 , wherein:
 a) said 312C2 is a mammalian protein, including a mouse or human;   b) said antibody is raised against a purified peptide sequence of SEQ ID NO: 2 or 4;   c) said antibody is a monoclonal antibody;   d) said antibody is detectably labeled;   e) said antibody is attached to a solid substrate;   f) said antibody is in a sterile composition; or   g) said antibody is in a buffered composition.   
     
     
         8 . A method of purifying a 312C2 protein or peptide from other materials in a mixture comprising contacting said mixture to an antibody of  claim 6 , and separating bound 312C2 from other materials. 
     
     
         9 . An isolated or recombinant nucleic acid capable of encoding a protein or peptide of  claim 1 . 
     
     
         10 . A nucleic acid of  claim 9 , wherein said nucleic acid:
 a) encodes a sequence of SEQ ID NO: 2 or 4;   b) comprises a sequence of SEQ ID NO: 1 or 3; or   c) encodes a sequence from an extracellular domain of a natural 312C2;   d) encodes a sequence from an intracellular domain of a natural 312C2;   e) attached to a solid substrate;   f) is detectable labeled; or   g) is in a sterile composition.   
     
     
         11 . An expression or replicating vector of  claim 9 . 
     
     
         12 . A kit comprising:
 a) a substantially pure 312C2 or fragment of  claim 1 ;   b) an antibody or receptor which specifically binds a 312C2; or   c) a nucleic acid encoding a 312C2 or peptide.   
     
     
         13 . A method for detecting in a sample the presence of a 312C2 nucleic acid, protein, or antibody, comprising testing said sample with a kit of  claim 12 . 
     
     
         14 . A method of modulating the physiology of a cell comprising contacting said cell with:
 a) a substantially pure 312C2 or fragment of  claim 1 ;   b) an antibody or binding partner which specifically binds a 312C2; or   c) a nucleic acid encoding a 312C2 or peptide.   
     
     
         15 . The method of  claim 14 , wherein said cell is a T cell and said modulating of physiology is:
 a) apoptosis of said T cell; or   b) activation of said T cell   
     
     
         16 . A method of  claim 14 , wherein said cell is in a tissue and/or in an organism. 
     
     
         17 . A method of expressing a 312C2 comprising expressing a nucleic acid of  claim 9 . 
     
     
         18 . A cell, tissue, organ, or organism comprising a nucleic acid of  claim 9 . 
     
     
         19 . A recombinant nucleic acid comprising sequence at least about 70% identity over a stretch of at least about 30 nucleotides to a 312C2 nucleic acid sequence of SEQ ID NO: 1 or 3. 
     
     
         20 . A nucleic acid of  claim 19 , further encoding a polypeptide comprising at least about 60% identity over a stretch of at least about 20 amino acids to a 312C2 sequence of SEQ ID NO: 2 or 4. 
     
     
         21 . A method of treating a host mammal having an abnormal immune response by administering to said mammal an effective dose of:
 a) an antibody or binding partner which binds specifically to a 312C2;   b) a substantially pure 312C2 protein or peptide thereof; or   c) a nucleic acid encoding a 312C2 peptide.   
     
     
         22 . The method of  claim 21 , wherein said abnormal immune response is characterized by:
 a) a T-cell immune deficiency;   b) chronic inflammation; or   c) tissue rejection.