DNA encoding B7, a new member of the Ig superfamily with unique expression on activated and neoplastic B cells

Abstract

Isolated nucleic acid molecules encoding a B cell activation antigen, B7, are provided. In one embodiment, the nucleic acid molecules are DNA sequences. The DNA sequences of the invention can be integrated into various expression vectors, which in turn can direct the synthesis of the corresponding proteins or peptides in a variety of hosts, particularly eukaryotic cells, such as mammalian and insect cell culture. Also provided are host cells transformed to produce proteins or peptides encoded by the DNA molecules of the present invention and purified proteins and peptides which comprise at least a portion of the B cell activation antigen. The proteins and peptides comprise at least a portion of the mature form of the B7 activation antigen and preferably comprise a soluble form of the B7 protein.

Having described the invention, what is claimed is:  
     
         1 . An isolated nucleic acid sequence coding for B lymphocyte activation antigen, B7.  
     
     
         2 . An isolated nucleic acid sequence according to  claim 1 , wherein the nucleic acid sequence is a cDNA sequence.  
     
     
         3 . An isolated nucleic acid sequence according to  claim 2 , wherein the DNA is of human origin.  
     
     
         4 . An isolated nucleic acid sequence according to  claim 2 , wherein the DNA is of murine origin.  
     
     
         5 . An isolated nucleic acid sequence according to  claim 4 , wherein the DNA of murine origin encodes a protein exhibiting about 40% identity with the human amino acid sequence set forth in SEQ ID NO:2.  
     
     
         6 . An isolated nucleic acid sequence according to  claim 5 , wherein the DNA of murine origin has substantially the nucleic acid sequence set forth in SEQ ID NO:3.  
     
     
         7 . A recombinant expression vector comprising a nucleic acid sequence according to  claim 1 .  
     
     
         8 . A recombinant expression vector according to  claim 7 , wherein the nucleic acid sequence is a cDNA sequence.  
     
     
         9 . A recombinant expression vector according to  claim 8 , wherein the cDNA is of human origin.  
     
     
         10 . A recombinant expression vector according to  claim 8 , wherein the cDNA is of murine origin.  
     
     
         11 . A recombinant expression vector according to  claim 9 , wherein the vector is a plasmid.  
     
     
         12 . A recombinant expression vector according to  claim 10 , wherein the vector is a plasmid.  
     
     
         13 . A host cell capable of expressing B7 activation antigen transformed by a recombinant expression vector according to  claim 11 .  
     
     
         14 . A host cell capable of expressing B7 activation antigen transformed by a recombinant expression vector according to  claim 12 .  
     
     
         15 . A substantially pure nucleic acid sequence coding for at least a portion of the coding region of the B7 B lymphocyte activation antigen set forth in SEQ ID NO:2 comprising amino acids −34 to 254.  
     
     
         16 . A substantially pure nucleic acid sequence according to  claim 15  wherein the nucleic acid is a DNA molecule of human origin.  
     
     
         17 . A substantially pure nucleic acid sequence according to  claim 16 , coding for a soluble form of the B7 activation antigen.  
     
     
         18 . A recombinant expression vector comprising a nucleic acid sequence according to  claim 17 .  
     
     
         19 . A host cell capable of expressing B7 activation antigen transformed by a recombinant expression vector according to claim 18.  
     
     
         20 . A substantially pure, recombinant protein expressed by a host cell according to  claim 19 .  
     
     
         21 . A substantially pure nucleic acid sequence coding for a B7 activation antigen which is identical with at least about 40% of the amino acids sequence set forth in SEQ ID NO:2 comprising amino acids −1 to 254.  
     
     
         22 . A substantially pure nucleic acid sequence according to  claim 21  of human origin and coding for the amino acid sequence set forth in SEQ ID NO:2.  
     
     
         24 . A substantially pure nucleic acid sequence according to  claim 21  of murine origin and coding for the amino acid sequence set forth in SEQ ID NO:3.  
     
     
         25 . A recombinant expression vector comprising a nucleic acid sequence according to  claim 24 .  
     
     
         26 . A host cell capable of expressing B7 activation antigen transformed by a recombinant expression vector according to  claim 25 .  
     
     
         27 . A recombinant protein expressed by a host cell according to  claim 26 .  
     
     
         28 . A substantially pure nucleic acid sequence comprising the nucleic acid sequence substantially as shown in SEQ ID NO:1 encoding a human B7 activation antigen.  
     
     
         29 . A substantially pure nucleic acid sequence comprising the nucleic acid sequence substantially as shown in SEQ ID NO:3 encoding a murine B7 activation antigen.  
     
     
         30 . A substantially pure B7 protein.  
     
     
         31 . A protein according to  claim 30  which is of human origin.  
     
     
         32 . A protein according to  claim 31  having the amino acid sequence set forth in SEQ ID NO: 2 or a fragment, mutant or variant thereof capable of either enhancing or suppressing an activated T cell mediated immune response.  
     
     
         33 . A protein according to  claim 30  which is of murine origin.  
     
     
         34 . A protein according to  claim 33  having the amino acid sequence set forth in SEQ ID NO: 4 or a fragment, mutant or variant thereof capable of either enhancing or suppressing an activated T cell mediated immune response.