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CDR3
Complementarity-determining regions (CDRs) are part of the variable chains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively, where these molecules bind to their specific antigen. A set of CDRs constitutes a paratope. As the most variable parts of the molecules, CDRs are crucial to the diversity of antigen specificities generated by lymphocytes. Location and structure There are three CDRs (CDR1, CDR2 and CDR3), arranged non-consecutively, on the amino acid sequence of a variable domain of an antigen receptor. Since the antigen receptors are typically composed of two variable domains (on two different polypeptide chains, heavy and light chain), there are six CDRs for each antigen receptor that can collectively come into contact with the antigen. A single antibody molecule has two antigen receptors and therefore contains twelve CDRs total. There are three CDR loops per variable domain in antibodies. Sixty CDRs can be found on a pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cell Receptor
The T-cell receptor (TCR) is a protein complex found on the surface of T cells, or T lymphocytes, that is 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 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. Each locus can produce a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibody With CDRs
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few varian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunoglobulins
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Domain
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few varia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratope
In immunology, a paratope, also known as an antigen-binding site, is the part of an antibody which recognizes and binds to an antigen. It is a small region at the tip of the antibody's antigen-binding fragment and contains parts of the antibody's heavy and light chains. Each paratope is made up of six complementarity-determining regions - three from each of the light and heavy chains - that extend from a fold of anti-parallel beta sheets. Each arm of the Y-shaped antibody has an identical paratope at the end. Paratopes make up the parts of the B-cell receptor that bind to and make contact with the epitope of an antigen. All the B-cell receptors on one B cell have identical paratopes. The uniqueness of a paratope allows it to bind to only one epitope with high affinity and as a result, each B cell can only respond to one epitope. The paratopes on B-cell receptors binding to their specific epitope is a critical step in the adaptive immune response. Design of paratopes between sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphocytes
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte". Lymphocytes make up between 18% and 42% of circulating white blood cells. Types The three major types of lymphocyte are T cells, B cells and natural killer (NK) cells. Lymphocytes can be identified by their large nucleus. T cells and B cells T cells ( thymus cells) and B cells ( bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies). The function of T cells and B cells is to recogn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-cells
A T cell is a type of lymphocyte. T cells are one of the important white blood cells 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" and CD4+ "helper" T cells. (These are named for the presence of the cell surface proteins CD8 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid Sequence
Protein primary structure is the linear sequence of amino acids in a peptide or protein. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthesis is most commonly performed by ribosomes in cells. Peptides can also be synthesized in the laboratory. Protein primary structures can be directly sequenced, or inferred from DNA sequences. Formation Biological Amino acids are polymerised via peptide bonds to form a long backbone, with the different amino acid side chains protruding along it. In biological systems, proteins are produced during translation by a cell's ribosomes. Some organisms can also make short peptides by non-ribosomal peptide synthesis, which often use amino acids other than the standard 20, and may be cyclised, modified and cross-linked. Chemical Peptides can be synthesised chemically via a range of laboratory methods. Chemical methods typically synthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-cells
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell. Additionally, B cells present antigens (they are also classified as professional antigen-presenting cells (APCs)) and secrete cytokines. In mammals, B cells mature in the bone marrow, which is at the core of most bones. In birds, B cells mature in the bursa of Fabricius, a lymphoid organ where they were first discovered by Chang and Glick, which is why the 'B' stands for bursa and not bone marrow as commonly believed. B cells, unlike the other two classes of lymphocytes, T cells and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunoglobulin Heavy Chain
The immunoglobulin heavy chain (IgH) is the large polypeptide subunit of an antibody (immunoglobulin). In human genome, the IgH gene loci are on chromosome 14. A typical antibody is composed of two immunoglobulin (Ig) heavy chains and two Ig light chains. Several different types of heavy chain exist that define the class or isotype of an antibody. These heavy chain types vary between different animals. All heavy chains contain a series of immunoglobulin domains, usually with one variable domain (VH) that is important for binding antigen and several constant domains (CH1, CH2, etc.). Production of a viable heavy chain is a key step in B cell maturation. If the heavy chain is able to bind to a surrogate light chain and move to the plasma membrane, then the developing B cell can begin producing its light chain. The heavy chain doesn't always have to bind to a light chain. Pre-B lymphocytes can synthesize heavy chain in the absence of light chain, which then can allow the heavy c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
