Lymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow, starting from hematopoietic stem cells Hematopoietic stem cells Progenitor cells from which all blood cells derived. They are found primarily in the bone marrow and also in small numbers in the peripheral blood. Bone Marrow: Composition and Hematopoiesis (HSCs) and progressing to common lymphoid progenitors Common lymphoid progenitors Stem cells from which B-lymphocytes; T-lymphocytes; natural killer cells; and some dendritic cells derive. Bone Marrow: Composition and Hematopoiesis ( CLPs CLPs Stem cells from which B-lymphocytes; T-lymphocytes; natural killer cells; and some dendritic cells derive. Bone Marrow: Composition and Hematopoiesis). B and T lymphocytes T lymphocytes Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. T cells: Types and Functions and natural killer (NK) cells arise from the lineage. B and T lymphocytes T lymphocytes Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. T cells: Types and Functions play a role in adaptive immunity, and NK cells provide host defense against atypical proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis such as tumor Tumor Inflammation cells. While all developmental stages begin in bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow, lymphocyte maturation differs. B lymphocytes B lymphocytes Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions and NK cells differentiate in bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow before migrating to secondary lymphoid organs Lymphoid organs A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs (such as lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy). T lymphocytes T lymphocytes Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. T cells: Types and Functions, however, proceed to the thymus Thymus A single, unpaired primary lymphoid organ situated in the mediastinum, extending superiorly into the neck to the lower edge of the thyroid gland and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat. Lymphatic Drainage System: Anatomy for further maturation.
Last updated: 9 Mar, 2022
Lymphocytes are blood cells involved in immune response, which arise from the common lymphoid progenitor (CLP).
White blood cells (WBCs), or
leukocytes
Leukocytes
White blood cells. These include granular leukocytes (basophils; eosinophils; and neutrophils) as well as non-granular leukocytes (lymphocytes and monocytes).
White Myeloid Cells: Histology, in the blood:
Granulocytes
Granulocytes
Leukocytes with abundant granules in the cytoplasm. They are divided into three groups according to the staining properties of the granules: neutrophilic, eosinophilic, and basophilic. Mature granulocytes are the neutrophils; eosinophils; and basophils.
White Myeloid Cells: Histology include basophil, eosinophil, and neutrophil;
agranulocytes
Agranulocytes
White Myeloid Cells: Histology include lymphocytes and
monocytes
Monocytes
Large, phagocytic mononuclear leukocytes produced in the vertebrate bone marrow and released into the blood; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.
Innate Immunity: Phagocytes and Antigen Presentation.
Bone
Bone
Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy.
Bones: Structure and Types-marrow
hematopoiesis
Hematopoiesis
The development and formation of various types of blood cells. Hematopoiesis can take place in the bone marrow (medullary) or outside the bone marrow (extramedullary hematopoiesis).
Bone Marrow: Composition and Hematopoiesis: proliferation and differentiation of the formed elements of blood.
IL-3:
interleukin-3
Interleukin-3
A multilineage cell growth factor secreted by lymphocytes; epithelial cells; and astrocytes which stimulates clonal proliferation and differentiation of various types of blood and tissue cells.
Platelets: Histology
CFU-GEMM
CFU-GEMM
Platelets: Histology:
colony-forming unit–granulocyte, erythrocyte, monocyte, megakaryocyte
Colony-forming unit–granulocyte, erythrocyte, monocyte, megakaryocyte
Platelets: Histology
IL-2:
interleukin-2
Interleukin-2
A soluble substance elaborated by antigen- or mitogen-stimulated T-lymphocytes which induces DNA synthesis in naive lymphocytes.
Interleukins
IL-6:
interleukin-6
Interleukin-6
A cytokine that stimulates the growth and differentiation of B-lymphocytes and is also a growth factor for hybridomas and plasmacytomas. It is produced by many different cells including T-lymphocytes; monocytes; and fibroblasts.
Interleukins
CFU-GM: colony-forming unit–granulocyte-macrophage
GM-CSF
GM-CSF
An acidic glycoprotein of mw 23 kda with internal disulfide bonds. The protein is produced in response to a number of inflammatory mediators by mesenchymal cells present in the hemopoietic environment and at peripheral sites of inflammation. GM-CSF is able to stimulate the production of neutrophilic granulocytes, macrophages, and mixed granulocyte-macrophage colonies from bone marrow cells and can stimulate the formation of eosinophil colonies from fetal liver progenitor cells. GM-CSF can also stimulate some functional activities in mature granulocytes and macrophages.
White Myeloid Cells: Histology: granulocyte-
macrophage colony-stimulating factor
Macrophage colony-stimulating factor
A mononuclear phagocyte colony-stimulating factor (M-CSF) synthesized by mesenchymal cells. The compound stimulates the survival, proliferation, and differentiation of hematopoietic cells of the monocyte-macrophage series. M-CSF is a disulfide-bonded glycoprotein dimer with a mw of 70 kda. It binds to a specific high affinity receptor.
White Myeloid Cells: Histology
M-CSF
M-CSF
A mononuclear phagocyte colony-stimulating factor (M-CSF) synthesized by mesenchymal cells. The compound stimulates the survival, proliferation, and differentiation of hematopoietic cells of the monocyte-macrophage series. M-CSF is a disulfide-bonded glycoprotein dimer with a mw of 70 kda. It binds to a specific high affinity receptor.
White Myeloid Cells: Histology:
macrophage colony-stimulating factor
Macrophage colony-stimulating factor
A mononuclear phagocyte colony-stimulating factor (M-CSF) synthesized by mesenchymal cells. The compound stimulates the survival, proliferation, and differentiation of hematopoietic cells of the monocyte-macrophage series. M-CSF is a disulfide-bonded glycoprotein dimer with a mw of 70 kda. It binds to a specific high affinity receptor.
White Myeloid Cells: Histology
G-CSF:
granulocyte colony-stimulating factor
Granulocyte colony-stimulating factor
A glycoprotein of mw 25 kda containing internal disulfide bonds. It induces the survival, proliferation, and differentiation of neutrophilic granulocyte precursor cells and functionally activates mature blood neutrophils. Among the family of colony-stimulating factors, G-CSF is the most potent inducer of terminal differentiation to granulocytes and macrophages of leukemic myeloid cell lines.
White Myeloid Cells: Histology
IL-5:
interleukin-5
Interleukin-5
A cytokine that promotes differentiation and activation of eosinophils. It also triggers activated B-lymphocytes to differentiate into immunoglobulin-secreting cells.
Interleukins
NK: natural killer
TPO:
thrombopoietin
Thrombopoietin
A humoral factor that stimulates the production of thrombocytes (blood platelets). Thrombopoietin stimulates the proliferation of bone marrow megakaryocytes and their release of blood platelets. The process is called thrombopoiesis.
Platelets: Histology
EPO
EPO
Glycoprotein hormone, secreted chiefly by the kidney in the adult and the liver in the fetus, that acts on erythroid stem cells of the bone marrow to stimulate proliferation and differentiation.
Erythrocytes: Histology:
erythropoietin
Erythropoietin
Glycoprotein hormone, secreted chiefly by the kidney in the adult and the liver in the fetus, that acts on erythroid stem cells of the bone marrow to stimulate proliferation and differentiation.
Erythrocytes: Histology
Cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response | Activities | Source |
---|---|---|
Stem cell factor Stem cell factor A hematopoietic growth factor and the ligand of the cell surface c-kit protein (proto-oncogene proteins c-kit). It is expressed during embryogenesis and is a growth factor for a number of cell types including the mast cells and the melanocytes in addition to the hematopoietic stem cells. Bone Marrow: Composition and Hematopoiesis (SCF) | Stimulates all hematopoietic progenitor cells | Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow stromal cells |
Interleukin-2 Interleukin-2 A soluble substance elaborated by antigen- or mitogen-stimulated T-lymphocytes which induces DNA synthesis in naive lymphocytes. Interleukins (IL-2) |
|
T helper cells |
Interleukin-4 Interleukin-4 A soluble factor produced by activated T-lymphocytes that induces the expression of mhc class II genes and fc receptors on B-lymphocytes and causes their proliferation and differentiation. It also acts on T-lymphocytes, mast cells, and several other hematopoietic lineage cells. Interleukins (IL-4) |
|
T helper cells |
Interleukin-6 Interleukin-6 A cytokine that stimulates the growth and differentiation of B-lymphocytes and is also a growth factor for hybridomas and plasmacytomas. It is produced by many different cells including T-lymphocytes; monocytes; and fibroblasts. Interleukins (IL-6) |
|
|
Interleukin-7 ( IL-7 IL-7 A proinflammatory cytokine produced primarily by T-lymphocytes or their precursors. Several subtypes of interleukin-17 have been identified, each of which is a product of a unique gene. Severe Combined Immunodeficiency (SCID)) | Stimulation of all lymphoid stem cells | Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow stromal cells |
The B cell receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors (BCR) consists of the immunoglobulin ( Ig Ig X-linked Agammaglobulinemia) molecule and the signaling molecule. Immunoglobin contains 2 identical heavy chains Heavy chains The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kda. Immunoglobulins: Types and Functions and 2 identical light chains Light chains Polypeptide chains, consisting of 211 to 217 amino acid residues and having a molecular weight of approximately 22 kda. There are two major types of light chains, kappa and lambda. Two ig light chains and two ig heavy chains (immunoglobulin heavy chains) make one immunoglobulin molecule. Immunoglobulins: Types and Functions linked by a disulfide bridge; the membrane-bound Ig Ig X-linked Agammaglobulinemia is anchored to the cell surface.
Image: “Figure 42 02 06” by OpenStax. License: CC BY 4.0To reach functionality, the B cell goes through stages in the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow and the secondary lymphoid organs Lymphoid organs A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs.Â
Maturation stage | Ig Ig X-linked Agammaglobulinemia genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure | BCR | Associated events |
---|---|---|---|
Pre-pro-B cell | Germline DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure | None | No heavy or light chain expression |
Pro-B cell | IGH D-J rearranged | None | Starts to express CD19, CD34, and HLA-DR (class II histocompatibility antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination) |
Pre-B cell | IGH V-D-J rearranged | Pre-BCR is formed:
|
Other markers appear (e.g., CD79, CD10, CD20, CD40 CD40 Members of the tumor necrosis factor receptor superfamily with specificity for CD40 ligand. They are found on mature B-lymphocytes, some epithelial cells; and lymphoid dendritic cells. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centers. Mutations in the CD40 antigen gene result in hyper-igm immunodeficiency syndrome, type 3. Signaling of the receptor occurs through its association with tnf receptor-associated factors. Hyper-IgM Syndrome, TdT TdT Acute Lymphoblastic Leukemia) |
Immature B cell |
|
Mature BCR ( IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions molecule) | HLA-DR, CD19, CD20, and CD40 CD40 Members of the tumor necrosis factor receptor superfamily with specificity for CD40 ligand. They are found on mature B-lymphocytes, some epithelial cells; and lymphoid dendritic cells. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centers. Mutations in the CD40 antigen gene result in hyper-igm immunodeficiency syndrome, type 3. Signaling of the receptor occurs through its association with tnf receptor-associated factors. Hyper-IgM Syndrome expression continues, but not other markers (e.g., CD10, CD34, TdT TdT Acute Lymphoblastic Leukemia) |
Mature B cell (naive) |
|
With mature BCR ( IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions) → exit bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow | Expression of CD19 and CD20 by all |
Maturation stage | BCR | Associated events |
---|---|---|
Mature B cell (in secondary lymphoid tissues) | Mature (expresses IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions and IgD IgD An immunoglobulin which accounts for less than 1% of plasma immunoglobulin. It is found on the membrane of many circulating B lymphocytes. Immunoglobulins: Types and Functions when in the secondary lymphoid tissues) | Cells can rest, or B cell activation B cell activation Humoral Adaptive Immunity can occur ( B cells B cells Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions interact with exogenous antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination and/or T helper cells). |
Activated B cell | Class-switch | Once activated, can remain as IgM IgM A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin. Immunoglobulins: Types and Functions or switch to IgE IgE An immunoglobulin associated with mast cells. Overexpression has been associated with allergic hypersensitivity. Immunoglobulins: Types and Functions, IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis, or IgA IgA Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory iga is the main immunoglobulin in secretions. Immunoglobulins: Types and Functions |
Memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment B cell |
|
|
Plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products cell |
|
Differentiation stages of the B cell:
In
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination-independent stages, B cell production starts with the hematopoietic stem cell (HSC), which becomes a common lymphoid progenitor (CLP), then a pre-pro–B cell or B-progenitor cell. The next steps include
gene
Gene
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Basic Terms of Genetics rearrangement to assemble the immunoglobulin (
Ig
Ig
X-linked Agammaglobulinemia) molecule. Immunoglobulin
heavy chains
Heavy chains
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kda.
Immunoglobulins: Types and Functions start with rearrangement of diversity and joining segments to form the pro-B cell. In the next step (pre-B cell),
Ig
Ig
X-linked Agammaglobulinemia heavy-chain
recombination
Recombination
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, crossing over; gene conversion; genetic transformation; genetic conjugation; genetic transduction; or mixed infection of viruses.
Virology (
variable
Variable
Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups.
Types of Variables, diversity, joining) is completed and the pre-B–cell
receptor
Receptor
Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.
Receptors is formed. Light-chain (kappa (κ) or lambda (λ)) rearrangement occurs resulting in the expression of a complete
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions-antibody molecule by an immature B cell. Formation of the mature B cell (naive) with both
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions and
IgD
IgD
An immunoglobulin which accounts for less than 1% of plasma immunoglobulin. It is found on the membrane of many circulating B lymphocytes.
Immunoglobulins: Types and Functions follows.
Antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination-dependent stages take place in secondary lymphoid tissues. Once the mature B cell produces
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions and
IgD
IgD
An immunoglobulin which accounts for less than 1% of plasma immunoglobulin. It is found on the membrane of many circulating B lymphocytes.
Immunoglobulins: Types and Functions, a class-switch can take place to make
IgE
IgE
An immunoglobulin associated with mast cells. Overexpression has been associated with allergic hypersensitivity.
Immunoglobulins: Types and Functions,
IgG
IgG
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.
Hypersensitivity Pneumonitis, and
IgA
IgA
Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory iga is the main immunoglobulin in secretions.
Immunoglobulins: Types and Functions.
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions are activated and become
plasma
Plasma
The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.
Transfusion Products cells or
memory cells
Memory cells
Cells that outlived a previous infection
Adaptive Immune Response.
Comparison of the B cell receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors (BCR) and the T cell receptor T cell receptor Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains. Adaptive Cell-mediated Immunity ( TCR TCR Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains. Adaptive Cell-mediated Immunity)
Image: “ Antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors chem114A” by Tinastella. License: Public DomainTo reach functionality, the T cell goes through stages, released from the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types marrow as progenitor cells to continue development in the thymus Thymus A single, unpaired primary lymphoid organ situated in the mediastinum, extending superiorly into the neck to the lower edge of the thyroid gland and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat. Lymphatic Drainage System: Anatomy.Â
Maturation stage | T cell receptor T cell receptor Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains. Adaptive Cell-mediated Immunity | Associated events |
---|---|---|
Progenitor cells | None |
|
Double-negative cells | Rearrangement of β chain (pre- TCR TCR Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains. Adaptive Cell-mediated Immunity) (failure to rearrange leads to apoptosis Apoptosis A regulated cell death mechanism characterized by distinctive morphologic changes in the nucleus and cytoplasm, including the endonucleolytic cleavage of genomic DNA, at regularly spaced, internucleosomal sites, I.e., DNA fragmentation. It is genetically-programmed and serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth. Ischemic Cell Damage) |
|
Double-positive cells | Rearrangement of É‘ chain → É‘ chains assemble with β chains → complete É‘-β– TCR TCR Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains. Adaptive Cell-mediated Immunity– CD3 CD3 Complex of at least five membrane-bound polypeptides in mature T-lymphocytes that are non-covalently associated with one another and with the T-cell receptor. The CD3 complex includes the gamma, delta, epsilon, zeta, and eta chains (subunits). When antigen binds to the T-cell receptor, the CD3 complex transduces the activating signals to the cytoplasm of the T-cell. The CD3 gamma and delta chains (subunits) are separate from and not related to the gamma/delta chains of the T-cell receptor. T cells: Types and Functions complex (expressed on the surface) |
|
Single-positive T cells T cells Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen. T cells: Types and Functions |
|
Differentiation stages of T cell:
From the
bone
Bone
Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy.
Bones: Structure and Types marrow, progenitor cells go to the
thymus
Thymus
A single, unpaired primary lymphoid organ situated in the mediastinum, extending superiorly into the neck to the lower edge of the thyroid gland and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
Lymphatic Drainage System: Anatomy for further maturation. The double-negative cells (no expression of CD4/CD8 or CD4-/CD8 -) have not developed the T-cell
receptor
Receptor
Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.
Receptors (
TCR
TCR
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains.
Adaptive Cell-mediated Immunity). The double-negative cells undergo rearrangement of the
TCR
TCR
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains.
Adaptive Cell-mediated Immunity
gene
Gene
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Basic Terms of Genetics and become pro-
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions, then pre-
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions. Through the series, CD4 and CD8 are expressed, and the
TCR
TCR
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains.
Adaptive Cell-mediated Immunity becomes assembled through
gene
Gene
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Basic Terms of Genetics rearrangements (double-positive cells). The
thymus
Thymus
A single, unpaired primary lymphoid organ situated in the mediastinum, extending superiorly into the neck to the lower edge of the thyroid gland and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
Lymphatic Drainage System: Anatomy then presents
major histocompatibility complex
Major histocompatibility complex
The genetic region which contains the loci of genes which determine the structure of the serologically defined (sd) and lymphocyte-defined (ld) transplantation antigens, genes which control the structure of the immune response-associated antigens, human; the immune response genes which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.
Innate Immunity: Phagocytes and Antigen Presentation (MHC) molecules to the developing
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions. Some cells undergo positive
selection
Selection
Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen.
B cells: Types and Functions (intermediate interaction between MHC and
TCR
TCR
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains.
Adaptive Cell-mediated Immunity takes place) and produce functional cells. Some cells undergo negative
selection
Selection
Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen.
B cells: Types and Functions (strong interaction between MHC and
TCR
TCR
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens. Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta or gamma-delta chains.
Adaptive Cell-mediated Immunity), which results in
cell death
Cell death
Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Apoptosis is programmed cell death, a mechanism with both physiologic and pathologic effects.
Cell Injury and Death. The
release
Release
Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane.
Virology of dysfunctional
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions, which can activate
autoimmunity
Autoimmunity
Autoimmunity is a pathologic immune response toward self-antigens, resulting from a combination of factors: immunologic, genetic, and environmental. The immune system is equipped with self-tolerance, allowing immune cells such as T cells and B cells to recognize self-antigens and to not mount a reaction against them. Defects in this mechanism, along with environmental triggers (such as infections) and genetic susceptibility factors (most notable of which are the HLA genes) can lead to autoimmune diseases.
Autoimmunity, is prevented. Some
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions fail to interact, leading to
apoptosis
Apoptosis
A regulated cell death mechanism characterized by distinctive morphologic changes in the nucleus and cytoplasm, including the endonucleolytic cleavage of genomic DNA, at regularly spaced, internucleosomal sites, I.e., DNA fragmentation. It is genetically-programmed and serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
Ischemic Cell Damage. Mature
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions express either CD4 (T helper cells) or CD8 (
cytotoxic
Cytotoxic
Parvovirus B19
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions), not both.