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Helper T-Cell (CD4+)
TH1
TH2
CD8 T-Cell
T-Cell or T-Lymphocyte
A lymphocyte that matures in the thymus and expresses a T-cell receptor, CD3, and CD4 or CD8. Several distinct T-cell subpopulations are
recognized.
A lymphocyte (white blood cell) that develops in the bone marrow, matures in the thymus, and works as part of the immune system in the
body.
different type of T-cell: T-helper cell (T4 cell, CD4 cell), T-killer cell (cytoxic T cells), T-suppressor cell (T8 cell, CD8 cell).
produce cytokine to help B-Lymphocyte to produce immunoglobuline
T cells also express what appear to be antibody molecules on their surfaces, but unlike B cells, these molecules cannot be secreted. This is
TCR T-Cell Receptor
Cytotoxic (Cytolytic) T cell: Cell that kills target cells bearing appropriate antigen within the groove of an MHC class I molecule that is identical
to that of the T cell.
Helper T cells A class of T cells which help trigger B cells to make antibody against thymus-dependent antigens. Helper T cells also help
generate cytotoxic T cells.
Killer T cell: A T cell with a particular immune specificity and an endogenously produced receptor for antigen, capable of specifically killing its
target cell after attachment to the target cell by this receptor. Also called cytotoxic T cell.
Suppressor T-cells The existance of these cells stems from recent discoveries and the functioning of these cells is still somewhat debated.
The basic concept of suppressor T-cells is a cell-type that specifically suppresses the action of other cells in the immune system, notably the
B-cells and the T-cells. Thereby preventing the establishment of an immune response. How this is done is not known with certainty, but it
seems that certain specific antigens can stimulate the activation of the suppressor T-cells. Discrete epitopes have been found, that have
suppressor activity on T-helper-cells and B-cells. The suppressor effection is thought to be mediated by some inhibitory factor, secreted by
suppressor T-cells. It is not any of the known lymphokines. Another fact that renders the study of this cell-type difficult is the lack of a specific
surface marker. Most suppressor T-cells are CD8 positive just as cytotoxic T-cells.
A subpopulation of T cells which act to reduce the immune responses of other T cells or B cell suppression. May be antigen-specific,
idiotype-specific, or non-specific in different circumstances.
Cytotoxic T-cell The cytotoxic T-cell has the simplest mode of action of the T-lymphocytes known. It has got the role of recognizing cells
infected with virus, or tumorcells, that produce proteins, that do not normally constitute the cell. The recognition takes place, when a
cytotoxic T-cell encounters a cell that display a Major-Histo-Compatibility-molecule class I (MHC-molecule classI) on the surface. The
MHC-molecule class I, shown bound to a nona-peptide (blue) below, can bind a specific peptide sequence of a foreign protein, that is being
synthesized intracellularly as a result of viral infection or by transformation into a tumor state.This way, the infected cell signals to the
surroundings, that it is infected and that it better be eliminated in order not to spread the infection. Membranebound T-cell-Receptors (
TcR's) on the cytotoxic CD8+ T-cells intercept this signal by specifically recognizing the MHC-molecule complexed with the foreign peptide.
The T-cells must just as B-cells have the ability to recognize a very wide spectra of MHC-peptide complexes. This task is overcome by the
T-cell by recombining the different gene segments, that encode the TcR. A feature also known from the immunoglobulin genes present in
the B-cell. In fact the TcR's are member of the immunoglobulin superfamily. This way a very broad array of TcR's can be produced with
virtually any kind of specificity. Some of the T-cell-receptors will initially have self-specificity, meaning, they recognize MHC-molecules class I,
complexed with part of a protein stemming from the normal cell. These T-cells however, are eliminated during the T-cell maturation in the
thymus. Once the MHC-classI-foreign peptide has been recognized by the TcR, a signal is transmitted to the interior of the T-cell and the
cytotoxic T-cell effectuate the cell-kiling by a lysis mechanism or by inducing programmed cell death (apoptosis) in the target cell just like
NK-cells. For this mechanism to start a signal must also come from the co-receptor molecule CD8. The CD8 molecule serves as a marker of
cytotoxic cells. As most cells are at risk for infections, MHC-molecules class I are present on nearlyt all celltypes in the body in contrast to
MHC-molecules class II, that are only present on the so-called antigen presenting cells, primarily macrophages and B-cells.
--------------------------------
T-Cells or Cytotoxic T-Cells (CD8+):
are responsible for Cell-Mediated Immune Responses (Cellular Immunology) - used to fight Virual Infections. #22
- Cytotoxic T-Cells (CD8+) are responsible for the destruction of host cells which have become infected by Viruses or other InterCellular
Pathogens. #30
Helper T-Cells (CD4+) - heighten the production of AntiBodies by B-Cells.
- A functional subclass of T-Cells which can help to generate Cytotoxic T-Cells (CD8+) and cooperate with B-Cells in the production of
AntiBody responses. Helper T-Cells recognize Antigens in association with Class II MHC molecules.
#30
Suppressor T-Cells - supress B-Cell activity and seem to be in short supply during a MS attack (exacerbation). #28
- A functionally defined population of T-Cells which reduce the Immune Responses of other T-Cells or B-Cells, or switch the response into a
different pathway. #30
TH1
TH2
CD8 T-Cell
T-Cell or T-Lymphocyte
A lymphocyte that matures in the thymus and expresses a T-cell receptor, CD3, and CD4 or CD8. Several distinct T-cell subpopulations are
recognized.
A lymphocyte (white blood cell) that develops in the bone marrow, matures in the thymus, and works as part of the immune system in the
body.
different type of T-cell: T-helper cell (T4 cell, CD4 cell), T-killer cell (cytoxic T cells), T-suppressor cell (T8 cell, CD8 cell).
produce cytokine to help B-Lymphocyte to produce immunoglobuline
T cells also express what appear to be antibody molecules on their surfaces, but unlike B cells, these molecules cannot be secreted. This is
TCR T-Cell Receptor
Cytotoxic (Cytolytic) T cell: Cell that kills target cells bearing appropriate antigen within the groove of an MHC class I molecule that is identical
to that of the T cell.
Helper T cells A class of T cells which help trigger B cells to make antibody against thymus-dependent antigens. Helper T cells also help
generate cytotoxic T cells.
Killer T cell: A T cell with a particular immune specificity and an endogenously produced receptor for antigen, capable of specifically killing its
target cell after attachment to the target cell by this receptor. Also called cytotoxic T cell.
Suppressor T-cells The existance of these cells stems from recent discoveries and the functioning of these cells is still somewhat debated.
The basic concept of suppressor T-cells is a cell-type that specifically suppresses the action of other cells in the immune system, notably the
B-cells and the T-cells. Thereby preventing the establishment of an immune response. How this is done is not known with certainty, but it
seems that certain specific antigens can stimulate the activation of the suppressor T-cells. Discrete epitopes have been found, that have
suppressor activity on T-helper-cells and B-cells. The suppressor effection is thought to be mediated by some inhibitory factor, secreted by
suppressor T-cells. It is not any of the known lymphokines. Another fact that renders the study of this cell-type difficult is the lack of a specific
surface marker. Most suppressor T-cells are CD8 positive just as cytotoxic T-cells.
A subpopulation of T cells which act to reduce the immune responses of other T cells or B cell suppression. May be antigen-specific,
idiotype-specific, or non-specific in different circumstances.
Cytotoxic T-cell The cytotoxic T-cell has the simplest mode of action of the T-lymphocytes known. It has got the role of recognizing cells
infected with virus, or tumorcells, that produce proteins, that do not normally constitute the cell. The recognition takes place, when a
cytotoxic T-cell encounters a cell that display a Major-Histo-Compatibility-molecule class I (MHC-molecule classI) on the surface. The
MHC-molecule class I, shown bound to a nona-peptide (blue) below, can bind a specific peptide sequence of a foreign protein, that is being
synthesized intracellularly as a result of viral infection or by transformation into a tumor state.This way, the infected cell signals to the
surroundings, that it is infected and that it better be eliminated in order not to spread the infection. Membranebound T-cell-Receptors (
TcR's) on the cytotoxic CD8+ T-cells intercept this signal by specifically recognizing the MHC-molecule complexed with the foreign peptide.
The T-cells must just as B-cells have the ability to recognize a very wide spectra of MHC-peptide complexes. This task is overcome by the
T-cell by recombining the different gene segments, that encode the TcR. A feature also known from the immunoglobulin genes present in
the B-cell. In fact the TcR's are member of the immunoglobulin superfamily. This way a very broad array of TcR's can be produced with
virtually any kind of specificity. Some of the T-cell-receptors will initially have self-specificity, meaning, they recognize MHC-molecules class I,
complexed with part of a protein stemming from the normal cell. These T-cells however, are eliminated during the T-cell maturation in the
thymus. Once the MHC-classI-foreign peptide has been recognized by the TcR, a signal is transmitted to the interior of the T-cell and the
cytotoxic T-cell effectuate the cell-kiling by a lysis mechanism or by inducing programmed cell death (apoptosis) in the target cell just like
NK-cells. For this mechanism to start a signal must also come from the co-receptor molecule CD8. The CD8 molecule serves as a marker of
cytotoxic cells. As most cells are at risk for infections, MHC-molecules class I are present on nearlyt all celltypes in the body in contrast to
MHC-molecules class II, that are only present on the so-called antigen presenting cells, primarily macrophages and B-cells.
--------------------------------
T-Cells or Cytotoxic T-Cells (CD8+):
are responsible for Cell-Mediated Immune Responses (Cellular Immunology) - used to fight Virual Infections. #22
- Cytotoxic T-Cells (CD8+) are responsible for the destruction of host cells which have become infected by Viruses or other InterCellular
Pathogens. #30
Helper T-Cells (CD4+) - heighten the production of AntiBodies by B-Cells.
- A functional subclass of T-Cells which can help to generate Cytotoxic T-Cells (CD8+) and cooperate with B-Cells in the production of
AntiBody responses. Helper T-Cells recognize Antigens in association with Class II MHC molecules.
#30
Suppressor T-Cells - supress B-Cell activity and seem to be in short supply during a MS attack (exacerbation). #28
- A functionally defined population of T-Cells which reduce the Immune Responses of other T-Cells or B-Cells, or switch the response into a
different pathway. #30
Antigen presenting cells (APC) are cells of the immune system that engulf dead or foreign cells and other material, which they chop up into
smaller sections. APCs present these fragments to T cells, which, in turn, initiate an immune response if the presented molecule stimulates
their receptors. In fact, most cells of the human body present antigens to the immune system, but the term, "antigen presenting cell", usually
refers to cells of the immune system.
smaller sections. APCs present these fragments to T cells, which, in turn, initiate an immune response if the presented molecule stimulates
their receptors. In fact, most cells of the human body present antigens to the immune system, but the term, "antigen presenting cell", usually
refers to cells of the immune system.
Bone marrow is a collection of soft spongy tissues found in the middle of most bones. It is the fourth largest organ in the body by weight,
following bone, muscle, and fat. The bone marrow is responsible for manufacturing all the blood cells although some of these cells are
further developed elsewhere in the body.
All cells in the body are made from precursor cells known as stem cells. There are different types of stem cell that mature into different
types of cell - many cell types go through several stages in their maturation process.
Both red blood cells (erythrocytes) and white blood cells (leukocytes) are produced from a type of stem or "blast" cell called a "totipotent"
cell. This process known as "hematopoiesis".
Totipotent stem cells develop into "multipotent" stem cells which go on to form red blood cells and "lymphoid" stem cells which are the
precursors of all white blood cells - the immune system cells.
Lymphoid stem cells further differentiated into various types of leukocyte - neutrophils, eosinophils, basophils, monocytes and
lymphocytes.
Lymphocytes diffentiate further into immature T-cells and B-cells in the marrow. The T-cells are released in an antigen independent state
and are further matured in a gland called the thymus. Along with another organ, the spleen, bone marrow serves as an
antigen-processing environment for B-cells.
following bone, muscle, and fat. The bone marrow is responsible for manufacturing all the blood cells although some of these cells are
further developed elsewhere in the body.
All cells in the body are made from precursor cells known as stem cells. There are different types of stem cell that mature into different
types of cell - many cell types go through several stages in their maturation process.
Both red blood cells (erythrocytes) and white blood cells (leukocytes) are produced from a type of stem or "blast" cell called a "totipotent"
cell. This process known as "hematopoiesis".
Totipotent stem cells develop into "multipotent" stem cells which go on to form red blood cells and "lymphoid" stem cells which are the
precursors of all white blood cells - the immune system cells.
Lymphoid stem cells further differentiated into various types of leukocyte - neutrophils, eosinophils, basophils, monocytes and
lymphocytes.
Lymphocytes diffentiate further into immature T-cells and B-cells in the marrow. The T-cells are released in an antigen independent state
and are further matured in a gland called the thymus. Along with another organ, the spleen, bone marrow serves as an
antigen-processing environment for B-cells.
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