Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 86; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 86). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. The CTLA-4 and B7-2 monomers are both two-layer beta-sandwiches that display the chain topology characteristic of the immunoglobulin variable (V-type) domains present in antigen receptors. The front and back sheets of B7-2 are composed of AGFCC'C" and BED strands, respectively. Members of the IgV family are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 beta-sheets with a tryptophan residue packed against the disulfide bond.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  20 VKRQAYFNSTAYLPCPFTKAQNISPSELVVFWQDRKKSVLYEHYLGAEKLDNVNAKYLGRTSFDRDNQALRLHNVQIKDT 99
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1958666122 100 GLYDCFIQQKTPTGSIILQQWETELSVI 127
Cdd:cd16087    81 GTYQCFIHHKSPKGLVLIHQMSSELSVI 108

Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 86; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 86). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. The CTLA-4 and B7-2 monomers are both two-layer beta-sandwiches that display the chain topology characteristic of the immunoglobulin variable (V-type) domains present in antigen receptors. The front and back sheets of B7-2 are composed of AGFCC'C" and BED strands, respectively. Members of the IgV family are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 beta-sheets with a tryptophan residue packed against the disulfide bond.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  20 VKRQAYFNSTAYLPCPFTKAQNISPSELVVFWQDRKKSVLYEHYLGAEKLDNVNAKYLGRTSFDRDNQALRLHNVQIKDT 99
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1958666122 100 GLYDCFIQQKTPTGSIILQQWETELSVI 127
Cdd:cd16087    81 GTYQCFIHHKSPKGLVLIHQMSSELSVI 108

Immunoglobulin constant (IgC)-like domain of antigen receptor Cluster of Differentiation (CD) 80; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin constant (IgC)-like domain of the antigen receptor Cluster of Differentiation (CD) 80. CD80 (also known as glycoprotein B7-1) and CD86 (also known as glycoprotein B7-2) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. CD80 contains two Ig-like domains, an amino-terminal immunoglobulin variable (IgV)-like domain characteristic of adhesion molecules, and a membrane proximal immunoglobulin constant (IgC)-like domain similar to the constant domains of antigen receptors. Members of the Ig family are components of immunoglobulin, T-cell receptors, CD1 cell surface glycoproteins, secretory glycoproteins A/C, and major histocompatibility complex (MHC) class I/II molecules. In immunoglobulins, each chain is composed of one variable domain (IgV) and one or more IgC domains. These names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. The IgV domain is responsible for antigen binding, and the IgC domain is involved in oligomerization and molecular interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122 130 FSEPEIEEAQNETRNTGiNLTCSSKQGYPKPTKMYflITNSTNEYGDNMQISQDNVTKLFSVSISLSLpfpDGVYNMTIV 209
Cdd:cd16083     1 FPVPSITEFGNPSPNIK-RIICSTSGGFPEPRLSW--LENGEELNAINTTVSQDPETELYTVSSELDF---NVTYNHSIV 74

                  ....
gi 1958666122 210 CILE 213
Cdd:cd16083    75 CLIK 78

Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 86; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 86). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. The CTLA-4 and B7-2 monomers are both two-layer beta-sandwiches that display the chain topology characteristic of the immunoglobulin variable (V-type) domains present in antigen receptors. The front and back sheets of B7-2 are composed of AGFCC'C" and BED strands, respectively. Members of the IgV family are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 beta-sheets with a tryptophan residue packed against the disulfide bond.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  20 VKRQAYFNSTAYLPCPFTKAQNISPSELVVFWQDRKKSVLYEHYLGAEKLDNVNAKYLGRTSFDRDNQALRLHNVQIKDT 99
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1958666122 100 GLYDCFIQQKTPTGSIILQQWETELSVI 127
Cdd:cd16087    81 GTYQCFIHHKSPKGLVLIHQMSSELSVI 108

Immunoglobulin Variable (IgV) domain of B7-H4; The members here are composed of the immunoglobulin variable (IgV) domain of B7-H4 (also known as B7-S1, B7x, or Vtcn1). B7-H4 is one of the B7 family of immune-regulatory ligands that act as negative regulators of T cell function; it contains one IgV domain and one IgC domain. The B7-family consists of structurally related cell-surface protein ligands, which bind to receptors on lymphocytes that regulate immune responses. The binding of B7-H4 to unidentified receptors results in the inhibition of TCR-mediated T cell proliferation, cell-cycle progression and IL-2 production. As a co-inhibitory molecule, B7-H4 is widely expressed in tumor tissues and its expression is significantly associated with poor prognosis in human cancers such as glioma, pancreatic cancer, oral squamous cell carcinoma, renal cell carcinoma, and lung cancer.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  24 AYFNSTAYLPCPFTKaqNISPSELVVFWQDRKKS-VLYEHYLGAEKLDNVNAKYLGRTSFDRD-----NQALRLHNVQIK 97
Cdd:cd20984     9 GNIGEDGILSCTFTP--DIKLSDIVIQWLKEGDSgLVHEFKEGKDELSRQSPMFRGRTSLFADqvhvgNASLRLKNVQLT 86

                          90
                  ....*....|....*.
gi 1958666122  98 DTGLYDCFIQQKTPTG 113
Cdd:cd20984    87 DAGTYLCIISNSKGTG 102

Immunoglobulin Variable (IgV) domain in HERV-H LTR-associating 2 (HHLA2); The members here are composed of the immunoglobulin variable (IgV) region in HERV-H LTR-associating 2 (HHLA2; also known as B7-H7/B7 homolog 7). HHLA2 is a member of the B7 family of immune regulatory proteins. Mature human HHLA2 consists of an extracellular domain (ECD) with three immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic domain. HHLA2 is widely expressed in human cancers including non-small cell lung carcinoma (NSCLS), triple negative breast cancer (TNBC), and melanoma, but has limited expression on normal tissues. Interestingly, unlike other members of B7 family, HHLA2 is not expressed in mice or rats. HHLA2 functions as a T cell coinhibitory molecules as it inhibits the proliferation of activated CD4(+) and CD8(+) T cells and their cytokine production. Furthermore, HHLA2 is constitutively expressed on the surface of human monocytes and is induced on B cells after stimulation, however it is not inducible on T cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  32 LPCPFTkaqniSPSELVVFWQDRKKS-VLYEHYLGAEKLDNVNAKYLGRTSFDRD-----NQALRLHNVQIKDTGLYDCF 105
Cdd:cd16091    17 LPCSFT-----PGSEVVIHWYKQDSDiKVHSYYYGKDQLESQDQRYRNRTSLFKDqisngNASLLLRRVQLQDEGRYKCY 91

                  .
gi 1958666122 106 I 106
Cdd:cd16091    92 T 92

Immunoglobulin Variable (IgV) domain of Programmed death ligand 1 (PD-L1); The members here are composed of the immunoglobulin variable (IgV) domain of Programmed death ligand 1 (PD-L1; also known as Cluster of Differentiation 274 (CD274)). PD-L1 is a cell-surface ligand that competes with PD-L2 for binding to the immunosuppressive receptor programmed death-1 (PD-1). PD-1 is a member of the B7 family that plays an important role in negatively regulating immune responses upon interaction with its two ligands, PD-L1 or PD-L2. Like PD-L2, PD-L1 interacts with PD-1 and suppresses T cell proliferation and cytokine production. The PD-1 receptor is expressed on the surface of activated T cells, while PD-L1 is expressed on cancer cells. When PD-1 and PD-L1 bind together, they form a molecular shield protecting tumor cells from being destroyed by the immune system. Thus, inhibiting the binding of PD-L1 to PD-1 with an antibody leads to killing of tumor cells by T cells. PD-1 inhibitors (such as Pembrolizumab, Nivolumab, and Cemiplimab) and PD-L1 inhibitors (such as Atezolizumab, Avelumab, and Durvalumab ) are an emerging class of immunotherapy that stimulate lymphocytes against tumor cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  26 FNSTAYLPCPFTKAQNISPSELVVFWQDRKKSVLyEHYLGAEKLDNVNAKYLGRTSFDRD-----NQALRLHNVQIKDTG 100
Cdd:cd20947    12 YGSNMTIECKFPVEKQLDLAALIVYWEMEDKNII-QFVHGEEDLKVQHSSYRQRARLLKDqlslgNAALQITDVKLQDAG 90

                  ....*.
gi 1958666122 101 LYDCFI 106
Cdd:cd20947    91 VYRCMI 96

Immunoglobulin variable domain (IgV) in Cluster of Differentiation (CD) 80; The members here are composed of the immunoglobulin variable region (IgV) in the Cluster of Differentiation (CD) 80). Glycoproteins B7-1 (also known as cluster of differentiation (CD) 80) and B7-2 (also known as CD86) are expressed on antigen-presenting cells and deliver the co-stimulatory signal through CD28 and CTLA-4 (also known as cluster of differentiation 152/CD152) on T cells. signaling through CD28 augments the T-cell response, whereas CTLA-4 signaling attenuates it. CD80 contains two Ig-like domains, an amino-terminal immunoglobulin variable (IgV)-like domain characteristic of adhesion molecules and a membrane proximal immunoglobulin constant (IgC)-like domain similar to the constant domains of antigen receptors. Members of the Ig family are components of immunoglobulin, T-cell receptors, CD1 cell surface glycoproteins, secretory glycoproteins A/C, and Major Histocompatibility Complex (MHC) class I/II molecules. In immunoglobulins, each chain is composed of one variable domain (IgV) and one or more IgC domains. These names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. The IgV domain is responsible for antigen binding, and the IgC domain is involved in oligomerization and molecular interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958666122  27 NSTAYLPCPFtkaqNISPSELV---VFWQDRKKSVLYehyLGAEKLdNVNAKYLGRTSFD-RDNQALRLHNVQIKDTGLY 102
Cdd:cd16086     9 KEKALLSCDY----NVSVDELAqvrIYWQKDDKMVLT---IISGDV-KVWPEYKNRTLFDiTNNLSIVILALRLSDRGTY 80

                  ....*..
gi 1958666122 103 DCFIQQK 109
Cdd:cd16086    81 TCVVQKK 87