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 1519311816  26 LKIQAYFNETADLPCQFANSQNQSLSELVVFWQDQENLVLNEVYLGKEKFDSVHSKYMGRTSFDSDSWTLRLHNLQIKDK 105
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1519311816 106 GLYQCIIHHKKPTGMIRIHQMNSELSVL 133
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 1519311816  26 LKIQAYFNETADLPCQFANSQNQSLSELVVFWQDQENLVLNEVYLGKEKFDSVHSKYMGRTSFDSDSWTLRLHNLQIKDK 105
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1519311816 106 GLYQCIIHHKKPTGMIRIHQMNSELSVL 133
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 1519311816 136 FSQPEIVPISNITENVYiNLTCSSIHGYPEPKkMSVL-----LRTKNSTIeydgvmqkSQDNVTELYDVSISLSVSfpdV 210
Cdd:cd16083     1 FPVPSITEFGNPSPNIK-RIICSTSGGFPEPR-LSWLengeeLNAINTTV--------SQDPETELYTVSSELDFN---V 67

                          90
                  ....*....|.
gi 1519311816 211 TSNMTIFCILE 221
Cdd:cd16083    68 TYNHSIVCLIK 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 1519311816  26 LKIQAYFNETADLPCQFANSQNQSLSELVVFWQDQENLVLNEVYLGKEKFDSVHSKYMGRTSFDSDSWTLRLHNLQIKDK 105
Cdd:cd16087     1 LKIQAYFNETAYLPCQFKNPQNISLSELVVFWQDQKKLVLYELYLGKEKLDNVNSKYIGRTSFDQENWTLQLHNVQIKDQ 80

                          90       100
                  ....*....|....*....|....*...
gi 1519311816 106 GLYQCIIHHKKPTGMIRIHQMNSELSVL 133
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 1519311816  30 AYFNETADLPCQFanSQNQSLSELVVFWQDQENL-VLNEVYLGKEKFDSVHSKYMGRTSFDSD-----SWTLRLHNLQIK 103
Cdd:cd20984     9 GNIGEDGILSCTF--TPDIKLSDIVIQWLKEGDSgLVHEFKEGKDELSRQSPMFRGRTSLFADqvhvgNASLRLKNVQLT 86

                          90
                  ....*....|....*.
gi 1519311816 104 DKGLYQCIIHHKKPTG 119
Cdd:cd20984    87 DAGTYLCIISNSKGTG 102

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 1519311816  33 NETADLPCQFaNSQNQSLSELVVFWQDQENLVLNeVYLGKEKfdsVHSKYMGRTSFD-SDSWTLRLHNLQIKDKGLYQCI 111
Cdd:cd16086     9 KEKALLSCDY-NVSVDELAQVRIYWQKDDKMVLT-IISGDVK---VWPEYKNRTLFDiTNNLSIVILALRLSDRGTYTCV 83

                          90       100
                  ....*....|....*....|.
gi 1519311816 112 IHHKKPTGMIRIHQMNSELSV 132
Cdd:cd16086    84 VQKKERGAYKREHLASVTLSV 104

Immunoglobulin Variable (IgV) domain of B7-H3, a member of the B7 family of immune checkpoint molecules; The members here are composed of the immunoglobulin variable (IgV) domain of B7-H3 also known as CD276), a member of the B7 family of immune checkpoint molecules. B7-H3 is an important immune checkpoint member of the B7 family and shares homology with other B7 ligands such as programmed death ligand 1 (PD-L1). The B7 family molecules interact with CD28 on T-cells to provide co-stimulatory signals that regulate T-cell activation and T-helper cell differentiation. Although B7-H3 has been shown to have both co-stimulatory and co-inhibitory effects on T-cell responses, the most current studies describe B7-H3 as a T cell inhibitor that promotes tumor aggressiveness and proliferation. Moreover, B7-H3 is highly overexpressed on a wide range of human solid cancers and promotes tumor growth, metastasis, and drug resistance. Thus, B7-H3 expression in tumors often correlates with both negative prognosis and poor clinical outcome in cancer patients. B7-H3 protein contains a predicted signal peptide, V- and C-like Ig domains (IgV and IgC), a transmembrane region, and an intracellular tail.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1519311816  30 AYFNETADLPCQFANSQNQSLSELVVFWQ--DQENLVlNEVYLGKEKFDSVHSKYMGRTSFDSD-----SWTLRLHNLQI 102
Cdd:cd20934     9 ALVGTDATLRCSFSPEPGFSLAQLSVFWQltDTKQLV-HSFTESQDQGRDQGSAYANRTALFPDllaqgNASLRLQRVRV 87

                          90
                  ....*....|
gi 1519311816 103 KDKGLYQCII 112
Cdd:cd20934    88 ADEGSYTCFV 97

First immunoglobulin variable (IgV) domain of poliovirus receptor (PVR, also known as CD155 and necl-5), and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and nectin-like protein 5 (necl-5)). Poliovirus (PV) binds to its cellular receptor (PVR/CD155) to initiate infection. CD155 is a membrane-anchored, single-span glycoprotein; its extracellular region has three Ig-like domains. There are four different isotypes of CD155 (referred to as alpha, beta, gamma, and delta), that result from alternate splicing of the CD155 mRNA, and have identical extracellular domains. CD155-beta and CD155-gamma are secreted; CD155-alpha and CD155-delta are membrane-bound and function as PV receptors. The virus recognition site is contained in the amino-terminal domain, D1. Having the virus attachment site on the receptor distal from the plasma membrane may be important for successful initiation of infection of cells by the virus. CD155 binds in the poliovirus "canyon" with a footprint similar to that of the intercellular adhesion molecule-1 receptor on human rhinoviruses. This group also includes the first Ig-like domain of nectin-1 (also known as poliovirus receptor related protein(PVRL)1; CD111), nectin-3 (also known as PVRL 3), nectin-4 (also known as PVRL4; LNIR receptor)and DNAX accessory molecule 1 (DNAM-1; CD226).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1519311816  24 APLKIQAYFNETADLPCQFANSQNQSLSElvVFWQDQENLVLNEVYLGKEKFD-SVHSKYMGRTSF-----DSDSWTLRL 97
Cdd:cd05718     5 VPTEVTGFLGGSVTLPCSLTSPGTTKITQ--VTWMKIGAGSSQNVAVFHPQYGpSVPNPYAERVEFlaarlGLRNATLRI 82

                          90
                  ....*....|...
gi 1519311816  98 HNLQIKDKGLYQC 110
Cdd:cd05718    83 RNLRVEDEGNYIC 95

Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1519311816  33 NETADLPCQFANSQNQSlsELVVFW------QDQENLVLNEVYLGKEKFDSVHskYMGRTSFDSDSWTLRLHNLQIKDKG 106
Cdd:pfam07686  11 GGSVTLPCTYSSSMSEA--STSVYWyrqppgKGPTFLIAYYSNGSEEGVKKGR--FSGRGDPSNGDGSLTIQNLTLSDSG 86

                          90       100
                  ....*....|....*....|....*..
gi 1519311816 107 LYQCIIHHKKPTGMIRIHQmnseLSVL 133
Cdd:pfam07686  87 TYTCAVIPSGEGVFGKGTR----LTVL 109