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Cd28
CD28 (Cluster of Differentiation 28) is a protein expressed on T cells that provides essential co-stimulation, co-stimulatory signals required for T cell activation and survival. When T cells are stimulated through CD28 in conjunction with the T-cell receptor (T cell receptor, TCR), it enhances the production of various interleukins, particularly interleukin 6, IL-6. CD28 serves as a receptor for CD80 (B7.1) and CD86 (B7.2), proteins found on antigen-presenting cells (APCs). CD28 is the only B7 (protein), B7 receptor consistently expressed on naive T cells. In the absence of CD28:B7 interaction, a naive T cell's TCR engagement with an Major histocompatibility complex, MHC:antigen complex leads to anergy. CD28 is also expressed on bone marrow stromal cells, plasma cells, neutrophils, and eosinophils, although its function in these cells is not fully understood. Typically, CD28 is expressed on about 50% of CD8, CD8+ T cells and more than 80% of CD4, CD4+ T cells in humans. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD80
The Cluster of differentiation 80 (also CD80 and B7-1) is a B7, type I membrane protein in the immunoglobulin superfamily, with an extracellular immunoglobulin constant-like domain and a variable-like domain required for receptor binding. It is closely related to CD86, another B7 protein (B7-2), and often works in tandem. Both CD80 and CD86 interact with Co-stimulation, costimulatory receptors CD28, CTLA-4 (CD152) and the p75 neurotrophin receptor. Structure CD80 is a member of the B7 (protein), B7 family, which consists of molecules present at Antigen-presenting cell, APCs and their receptors present on the T cell, T-cells. CD80 is present specifically on Dendritic cell, DC, activated B cell, B-cells, and macrophages, but also T cell, T-cells. CD80 is also a Transmembrane protein, transmembrane glycoprotein and a member of the Immunoglobulin superfamily, Ig superfamily. It is composed of 288 amino acids, and its mass is 33 Dalton (unit), kDa. It consists of two Ig-like extracel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD86
Cluster of Differentiation 86 (also known as CD86 and B7-2) is a protein constitutively expressed on dendritic cells, Langerhans cells, macrophages, B-cells (including memory B-cells), and on other antigen-presenting cells. Along with CD80, CD86 provides costimulatory signals necessary for T cell activation and survival. Depending on the ligand bound, CD86 can signal for self-regulation and cell-cell association, or for attenuation of regulation and cell-cell disassociation. The ''CD86'' gene encodes a type I membrane protein that is a member of the immunoglobulin superfamily. Alternative splicing results in two transcript variants encoding different isoforms. Additional transcript variants have been described, but their full-length sequences have not been determined. Structure CD86 belongs to the B7 family of the immunoglobulin superfamily. It is a 70 kDa glycoprotein made up of 329 amino acids. Both CD80 and CD86 share a conserved amino acid motif that forms their l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B7 (protein)
B7 is a type of integral membrane protein found on activated antigen-presenting cells (APC) that, when paired with either a CD28 or CD152 (CTLA-4) surface protein on a T cell, can produce a costimulatory signal or a coinhibitory signal to enhance or decrease the activity of a MHC- TCR signal between the APC and the T cell, respectively. Binding of the B7 of APC to CTLA-4 of T-cells causes inhibition of the activity of T-cells. There are two major types of B7 proteins: B7-1 or CD80, and B7-2 or CD86. It is not known if they differ significantly from each other. So far CD80 is found on dendritic cells, macrophages, and activated B cells, CD86 (B7-2) on B cells. The proteins CD28 and CTLA-4 ( CD152) each interact with both B7-1 and B7-2. Costimulation There are several steps to activation of the immune system against a pathogen. The T-cell receptor must first interact with the Major histocompatibility complex (MHC) surface protein. The CD4 or CD8 proteins on the T-cell surface for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-stimulation
Co-stimulation is a secondary signal which immune cells rely on to activate an immune response in the presence of an antigen-presenting cell. In the case of T cells, two stimuli are required to fully activate their immune response. During the activation of lymphocytes, co-stimulation is often crucial to the development of an effective immune response. Co-stimulation is required in addition to the antigen-specific signal from their antigen receptors. T cell co-stimulation T cells require two signals to become fully activated. A first signal, which is antigen-specific, is provided through the T cell receptor (TCR) which interacts with peptide- MHC molecules on the membrane of an antigen presenting cell (APC). A second signal, the co-stimulatory signal, is antigen nonspecific and is provided by the interaction between co-stimulatory molecules expressed on the membrane of the APC and the T cell. This interaction promotes and enhances the TCR signaling, but can also be bi-directional. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cells
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: CD8+ "killer" (cytotoxic) and CD4+ "helper" T cells. (These are named for the presence of the cell surface proteins CD8 or CD4.) CD8+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TEC (gene)
Tyrosine-protein kinase Tec is a tyrosine kinase that in humans is encoded by the ''TEC'' gene. Tec kinase is expressed in hematopoietic, liver, and kidney cells and plays an important role in T-helper cell processes. Tec kinase is the name-giving member of the Tec kinase family, a family of non-receptor protein-tyrosine kinases. Structure Tec kinase contains five protein interaction domains. The characteristic feature of Tec family kinases is a pleckstrin homology (PH) domain on the N-terminus of the molecule followed by a Tec homology (TH) domain. The TH domain of Tec kinase contains a Btk homology (BH) motif and two proline-rich (PR) regions. The other protein interaction domains of Tec kinase include Src homology (SH) domains SH2 and SH3 and a kinase domain with enzymatic activity. ''TEC'' produces two protein isoforms that differ in the SH3 domain through alternative splicing. Type IV isoform has a full length SH3 domain and is predominately expressed in hematopoietic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PKCθ
Protein kinase C theta (PKC-θ) is an enzyme that in humans is encoded by the ''PRKCQ'' gene. PKC-θ, a member of serine/threonine kinases, is mainly expressed in hematopoietic cells with high levels in platelets and T lymphocytes, where plays a role in signal transduction. Different subpopulations of T cells vary in their requirements of PKC-θ, therefore PKC-θ is considered as a potential target for inhibitors in the context of immunotherapy. Function Protein kinase C (PKC) is a family of serine- and threonine-specific protein kinases that can be activated by the second messenger diacylglycerol. PKC family members phosphorylate a wide variety of protein targets and are known to be involved in diverse cellular signaling pathways. PKC family members also serve as major receptors for phorbol esters, a class of tumor promoters. Each member of the PKC family has a specific expression profile and is believed to play a distinct role. The protein encoded by this gene is one of the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRAP2
GRB2-related adapter protein 2 also known as GRB2-related adaptor downstream of Shc (GADS) is a 37 kDa protein that in humans is encoded by the ''GRAP2'' gene. Function This gene encodes a member of the GRB2/Sem5/Drk family. This member is an adaptor-like protein involved in leukocyte-specific protein-tyrosine kinase signaling. Like its related family member, GRB2-related adaptor protein (GRAP), this protein contains an SH2 domain flanked by two SH3 domains. This protein interacts with other proteins, such as GRB2-associated binding protein 1 (GAB1) and the SLP-76 leukocyte protein (LCP2), through its SH3 domains. Transcript variants utilizing alternative polyA sites exist. Interactions GRAP2 has been shown to interact with: * CCNDBP1, * CD28, * Linker of activated T cells, * Lymphocyte cytosolic protein 2 * MAP4K1 Mitogen-activated protein kinase kinase kinase kinase 1 is a protein kinase that in humans is encoded by the ''MAP4K1'' gene. It is also known as HP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interleukin 2
Interleukin-2 (IL-2) is an interleukin, which is a type of cytokine signaling molecule forming part of the immune system. It is a 15.5–16 Dalton (unit), kDa protein that regulates the activities of white blood cells (leukocytes, often lymphocytes) that are responsible for immunity. IL-2 is part of the body's immune response, natural response to microbial infection, and in discriminating between foreign ("non-self") and "self". IL-2 mediates its effects by binding to IL-2 receptors, which are expressed by lymphocytes. The major sources of IL-2 are activated T helper cell, CD4+ T cells and activated CD8+ T cells, CD8+ T cells. Put shortly the function of IL-2 is to stimulate the growth of helper, cytotoxic and regulatory T cells. IL-2 receptor IL-2 is a member of a specific family of cytokines, each member of which has a Helix bundle#Four-helix bundles, four alpha helix bundle; this cytokine family also includes Interleukin-4, IL-4, Interleukin 7, IL-7, Interleukin 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grb2
Growth factor receptor-bound protein 2, also known as Grb2, is an adaptor protein involved in signal transduction/ cell communication. In humans, the GRB2 protein is encoded by the ''GRB2'' gene. The protein encoded by this gene binds receptors such as the epidermal growth factor receptor and contains one SH2 domain and two SH3 domains. Its two SH3 domains direct complex formation with proline-rich regions of other proteins, and its SH2 domain binds tyrosine phosphorylated sequences. This gene is similar to the ''sem-5'' gene of ''Caenorhabditis elegans'', which is involved in the signal transduction pathway. Two alternatively spliced transcript variants encoding different isoforms have been found for this gene. Function and expression Grb2 is widely expressed and is essential for multiple cellular functions. Inhibition of Grb2 function impairs developmental processes in various organisms and blocks transformation and proliferation of various cell types. It is thus n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immune Synapse
In immunology, an immunological synapse (or immune synapse) is the interface between an antigen-presenting cell or target cell and a lymphocyte such as a T cell, B cell, or natural killer cell. The interface was originally named after the neuronal synapse, with which it shares the main structural pattern. An immunological synapse consists of molecules involved in T cell activation, which compose typical patterns—activation clusters. Immunological synapses are the subject of much ongoing research. Structure and function The immune synapse is also known as the supramolecular activation cluster or SMAC. This structure is composed of concentric rings each containing segregated clusters of proteins—often referred to as the bull’s-eye model of the immunological synapse: * c-SMAC (central-SMAC) composed of the θ isoform of protein kinase C, CD2, CD4, CD8, CD28, Lck, and Fyn. * p-SMAC (peripheral-SMAC) within which the lymphocyte function-associated antigen-1 ( LFA-1) and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cell Receptor
The T-cell receptor (TCR) is a protein complex, located on the surface of T cells (also called T lymphocytes). They are responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. The binding between TCR and antigen peptides is of relatively low affinity and is biologically degenerate (that is, many TCRs recognize the same antigen peptide, and many antigen peptides are recognized by the same TCR). The TCR is composed of two different protein chains (that is, it is a hetero dimer). In humans, in 95% of T cells the TCR consists of an alpha (α) chain and a beta (β) chain (encoded by ''TRA'' and ''TRB'', respectively), whereas in 5% of T cells the TCR consists of gamma and delta (γ/δ) chains (encoded by '' TRG'' and '' TRD'', respectively). This ratio changes during ontogeny and in diseased states (such as leukemia). It also differs between species. Orthologues of the 4 loci have been mapped in various species. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
