B-7 domain-specific antibodies

Abstract

Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

1 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 comprising a contiguous nucleotide sequence derived from at least one T cell costimulatory molecule gene, the nucleotide sequence represented by a formula A-B-C-D-E, wherein 
 A comprises a nucleotide sequence of at least one first exon of a T cell costimulatory molecule gene, wherein the at least one first exon encodes a signal peptide domain,    B comprises a nucleotide sequence of at least one second exon of a T cell costimulatory molecule gene, wherein the at least one second exon encodes an immunoglobulin variable region-like domain,    C comprises a nucleotide sequence of at least one third exon of a T cell costimulatory molecule gene, wherein the at least one third exon encodes an immunoglobulin constant region-like domain,    D comprises a nucleotide sequence of at least one fourth exon of a T cell costimulatory molecule gene, wherein the at least one fourth exon encodes a transmembrane domain, and    E comprises a nucleotide sequence of at least one fifth exon of a T cell costimulatory molecule gene, wherein the at least one fifth exon encodes a cytoplasmic domain,    with the proviso that E does not comprise a nucleotide sequence selected from a group consisting of SEQ ID NO:25, SEQ ID NO:27, SEQ ID NO:29 and SEQ ID NO:31.    
     
     
         2 . The isolated nucleic acid of  claim 1  which is a cDNA.  
     
     
         3 . The isolated nucleic acid of  claim 2  which comprises a coding region of the cDNA.  
     
     
         4 . The isolated nucleic acid of  claim 1 , wherein the nucleotide sequence is derived from a T cell costimulatory molecule gene encoding B7-1.  
     
     
         5 . The isolated nucleic acid of  claim 4 , wherein B7-1 is murine.  
     
     
         6 . The isolated nucleic acid of  claim 4 , wherein B7-1 is human.  
     
     
         7 . The isolated nucleic acid of  claim 5 , wherein E comprises a nucleotide sequence shown in SEQ ID NO:4.  
     
     
         8 . The isolated nucleic acid of  claim 5 , wherein E comprises a nucleotide sequence encoding an amino acid sequence shown in SEQ ID NO:5.  
     
     
         9 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 and is encoded by a T cell costimulatory molecule gene having 
 at least one first exon encoding a first cytoplasmic domain comprising a nucleotide sequence selected from the group consisting of a nucleotide sequence of SEQ ID NO:25, SEQ ID NO:27, SEQ ID NO:29 and SEQ ID NO:31, and    at least one second exon encoding a second cytoplasmic domain, wherein the isolated nucleic acid comprises a nucleotide sequence encoding the second cytoplasmic domain.    
     
     
         10 . The isolated nucleic acid of  claim 9  which comprises a coding region of a cDNA.  
     
     
         11 . The isolated nucleic acid of  claim 9  which does not comprise a nucleotide sequence encoding the first cytoplasmic domain.  
     
     
         12 . The isolated nucleic acid of  claim 9  wherein the T cell costimulatory molecule gene is B7-1.  
     
     
         13 . The isolated nucleic acid of  claim 12  wherein B7-1 is murine.  
     
     
         14 . The isolated nucleic acid of  claim 12  wherein B7-1 is human.  
     
     
         15 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 comprising a nucleotide sequence shown in SEQ ID NO: 1.  
     
     
         16 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 comprising a nucleotide sequence shown in SEQ ID NO:3.  
     
     
         17 . An isolated nucleic acid encoding a cytoplasmic domain derived from a protein which binds CD28 or CTLA4, the nucleic acid comprising a nucleotide sequence shown in SEQ ID NO:4.  
     
     
         18 . A recombinant expression vector comprising the nucleic acid molecule of  claim 15 .  
     
     
         19 . A host cell which contains the recombinant expression vector of  claim 18 .  
     
     
         20 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 comprising a contiguous nucleotide sequence derived from at least one T cell costimulatory molecule gene, the nucleotide sequence represented by a formula A-B-C-D-E, wherein 
 A comprises a nucleotide sequence of at least one first exon of a T cell costimulatory molecule gene, wherein the at least one first exon encodes a signal peptide domain,    B comprises a nucleotide sequence of at least one second exon of a T cell costimulatory molecule gene, wherein the at least one second exon encodes an immunoglobulin variable region-like domain,    C comprises a nucleotide sequence of at least one third exon of a T cell costimulatory molecule gene, wherein the at least one third exon encodes an immunoglobulin constant region-like domain,    D, which may or may not be present, comprises a nucleotide sequence of at least one fourth exon of a T cell costimulatory molecule gene, wherein the at least one fourth exon encodes a transmembrane domain, and    E, which may or may not be present, comprises a nucleotide sequence of at least one fifth exon of a T cell costimulatory molecule gene, wherein the at least one fifth exon encodes a cytoplasmic domain,    with the proviso that A does not comprise a nucleotide sequence selected from a group consisting of SEQ ID NO:33, SEQ ID NO:35, SEQ ID NO:37, SEQ ID NO:39 and SEQ ID NO:41.    
     
     
         21 . The isolated nucleic acid of  claim 20  which is a cDNA.  
     
     
         22 . The isolated nucleic acid of  claim 21  which comprises a coding region of the cDNA.  
     
     
         23 . The isolated nucleic acid of  claim 20 , wherein the nucleotide sequence is derived from a T cell costimulatory molecule gene encoding B7-2.  
     
     
         24 . The isolated nucleic acid of  claim 23 , wherein B7-2 is murine.  
     
     
         25 . The isolated nucleic acid of  claim 23 , wherein B7-2 is human.  
     
     
         26 . The isolated nucleic acid of  claim 24 , wherein A comprises a nucleotide sequence selected from the group consisting of SEQ ID NO: 14.  
     
     
         27 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 and is encoded by a T cell costimulatory molecule gene having 
 at least one first exon encoding a first signal peptide domain comprising a nucleotide sequence selected from the group consisting of a nucleotide sequence of SEQ ID NO:33, SEQ ID NO:35, SEQ ID NO:37 SEQ ID NO:39 and SEQ ID NO:41, and    at least one second exon encoding a second signal peptide domain, wherein the isolated nucleic acid comprises a nucleotide sequence encoding the second signal peptide domain.    
     
     
         28 . The isolated nucleic acid of  claim 27  which comprises a coding region of a cDNA.  
     
     
         29 . The isolated nucleic acid of  claim 27  which does not comprise a nucleotide sequence encoding the first signal peptide domain.  
     
     
         30 . The isolated nucleic acid of  claim 27  wherein the T cell costimulatory molecule gene is B7-2.  
     
     
         31 . The isolated nucleic acid of  claim 30  wherein B7-2 is murine.  
     
     
         32 . The isolated nucleic acid of  claim 30  wherein B7-2 is human.  
     
     
         33 . An isolated nucleic acid encoding a protein which binds CD28 or CTLA4 comprising a nucleotide sequence shown in SEQ ID NO:12.  
     
     
         34 . An isolated nucleic acid encoding a signal peptide domain derived from a protein which binds CD28 or CTLA4, the nucleic acid comprising a nucleotide sequence shown in SEQ ID NO:14.  
     
     
         35 . A recombinant expression vector comprising the nucleic acid molecule of  claim 33 .  
     
     
         36 . A host cell which contains the recombinant expression vector of  claim 35 .  
     
     
         37 . An isolated nucleic acid encoding a protein comprising a contiguous nucleotide sequence derived from at least one T cell costimulatory molecule gene, the nucleotide sequence represented by a formula A-B-C-D, wherein 
 A comprises a nucleotide sequence of at least one first exon of a T cell costimulatory molecule gene, wherein the at least one first exon encodes a signal peptide domain,    B comprises a nucleotide sequence of at least one second exon of a T cell costimulatory molecule gene, wherein the at least one second exon encodes an immunoglobulin constant region-like domain,    C comprises a nucleotide sequence of at least one third exon of a T cell costimulatory molecule gene, wherein the at least one third exon encodes a transmembrane domain, and    D comprises a nucleotide sequence of at least one fourth exon of a T cell costimulatory molecule gene, wherein the at least one fourth exon encodes a cytoplasmic domain.    
     
     
         38 . The isolated nucleic acid of  claim 37  comprising a nucleotide sequence shown in SEQ ID NO:8.  
     
     
         39 . The isolated nucleic acid of  claim 37  comprising a nucleotide sequence shown in SEQ ID NO:10.