B7-like molecules and uses thereof

An isolated nucleic acid molecule comprising a nucleotide sequence selected from the group consisting of:

• (a) a nucleotide sequence encoding a polypeptide which is at least about 70 percent identical to the polypeptide as set forth in SEQ ID NO:
• 2, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (b) a nucleotide sequence encoding an allelic variant or splice variant of the nucleotide sequence as set forth in SEQ ID NO:
• 1 or (a);
• (c) a region of the nucleotide sequence of SEQ ID NO:
• 1, (a), or (b) encoding a polypeptide fragment of at least about 25 amino acid residues, wherein the polypeptide fragment has an activity of the encoded polypeptide as set forth in SEQ ID NO:
• 2, or is antigenic;
• (d) a region of the nucleotide sequence of SEQ ID NO:
• 1 or any of (a)-(c) comprising a fragment of at least about 16 nucleotides;
• (e) a nucleotide sequence which hybridizes under moderately or highly stringent conditions to the complement of any of (a)-(d);
• and
• (f) a nucleotide sequence complementary to any of (a)-(d).

An isolated nucleic acid molecule comprising a nucleotide sequence selected from the group consisting of:

• (a) a nucleotide sequence encoding a polypeptide as set forth in SEQ ID NO:
• 2 with at least one conservative amino acid substitution, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (b) a nucleotide sequence encoding a polypeptide as set forth in SEQ ID NO:
• 2 with at least one amino acid insertion, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (c) a nucleotide sequence encoding a polypeptide as set forth in SEQ ID NO:
• 2 with at least one amino acid deletion, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (d) a nucleotide sequence encoding a polypeptide as set forth in SEQ ID NO:
• 2 which has a C- and/or N-terminal truncation, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (e) a nucleotide sequence encoding a polypeptide as set forth in SEQ ID NO:
• 2 with at least one modification selected from the group consisting of amino acid substitutions, amino acid insertions, amino acid deletions, C-terminal truncation, and N-terminal truncation, wherein the encoded polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (f) a nucleotide sequence of any of (a)-(e) comprising a fragment of at least about 16 nucleotides;
• (g) a nucleotide sequence which hybridizes under moderately or highly stringent conditions to the complement of any of (a)-(f);
• and
• (h) a nucleotide sequence complementary to any of (a)-(e).

An isolated polypeptide comprising the amino acid sequence selected from the group consisting of:

• (a) the amino acid sequence as set forth in SEQ ID NO:
• 3, optionally further comprising an amino-terminal methionine;
• (b) an amino acid sequence for an ortholog of SEQ ID NO:
• 2;
• (c) an amino acid sequence which is at least about 70 percent identical to the amino acid sequence of SEQ ID NO:
• 2, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (d) a fragment of the amino acid sequence set forth in SEQ ID NO:
• 2 comprising at least about 25 amino acid residues, wherein the fragment has an activity of the polypeptide set forth in SEQ ID NO:
• 2, or is antigenic;
• and
• (e) an amino acid sequence for an allelic variant or splice variant of the amino acid sequence as set forth in SEQ ID NO:
• 2 or any of (a)-(c).

An isolated polypeptide comprising the amino acid sequence selected from the group consisting of:

• (a) the amino acid sequence as set forth in SEQ ID NO:
• 2 with at least one conservative amino acid substitution, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (b) the amino acid sequence as set forth in SEQ ID NO:
• 2 with at least one amino acid insertion, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (c) the amino acid sequence as set forth in SEQ ID NO:
• 2 with at least one amino acid deletion, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• (d) the amino acid sequence as set forth in SEQ ID NO:
• 2 which has a C- and/or N-terminal truncation, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2;
• and
• (e) the amino acid sequence as set forth in SEQ ID NO:
• 2 with at least one modification selected from the group consisting of amino acid substitutions, amino acid insertions, amino acid deletions, C-terminal truncation, and N-terminal truncation, wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2.

An isolated polypeptide comprising the amino acid sequence as set forth in SEQ ID NO:

• 2 with at least one conservative amino acid substitution selected from the group consisting of:
• methionine at position 4;
• leucine or methionine at position 12;
• leucine or valine at position 13;
• leucine or valine at position 16;
• leucine or valine at position 17;
• leucine, valine, or methionine at position 18;
• leucine or valine at position 23;
• leucine at position 26;
• leucine or valine at position 27;
• valine or leucine at position 31;
• leucine or isoleucine at position 39;
• alanine at position 46;
• valine at position 48;
• alanine at position 52;
• isoleucine at position 54;
• glutamic acid at position 61;
• valine at position 64;
• glutamic acid at position 66;
• leucine, methionine, or valine at position 67;
• valine or leucine at position 69;
• arginine at position 73;
• leucine at position 76;
• valine at position 79;
• methionine at position 80;
• tyrosine at position 83;
• arginine at position 84;
• aspartic acid at position 85;
• arginine at position 87;
• glutamic acid at position 88;
• aspartic acid at position 92;
• tyrosine at position 97;
• lysine at position 98;
• leucine, isoleucine, or methionine at position 103;
• isoleucine, leucine, or methionine at position 108;
• isoleucine at position 115;
• isoleucine at position 117;
• leucine or isoleucine at position 120;
• valine or isoleucine at position 122;
• serine at position 123;
• glutamic acid at position 124;
• serine at position 127;
• phenylalanine at position 128;
• arginine at position 129;
• phenylalanine at position 131;
• valine at position 132;
• alanine at position 137;
• valine or isoleucine at position 143;
• alanine at position 148;
• glycine at position 149;
• isoleucine or methionine at position 155;
• isoleucine or methionine at position 157;
• isoleucine at position 166;
• tyrosine at position 174;
• isoleucine, leucine, or methionine at position 179;
• isoleucine at position 180;
• leucine at position 194;
• phenylalanine at position 215;
• serine at position 218;
• serine at position 222;
• isoleucine or leucine at position 226;
• valine or leucine at position 227;
• leucine or valine at position 231;
• isoleucine at position 240;
• aspartic acid at position 242;
• methionine or leucine at position 245;
• arginine at position 246;
• threonine at position 256;
• valine or isoleucine at position 260;
• leucine or isoleucine at position 262;
• leucine or valine at position 268;
• valine or methionine at position 272;
• valine at position 273;
• valine, isoleucine, or methionine at position 275;
• phenylalanine at position 278;
• valine or isoleucine at position 279;
• isoleucine or valine at position 281;
• and arginine at position 282;
• wherein the polypeptide has an activity of the polypeptide set forth in SEQ ID NO:
• 2.