Lymphocyte: Difference between revisions
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A '''lymphocyte''' is a | A '''lymphocyte''' is a type of [[leukocyte]] (i.e., white blood cell), which are a major component of the immune system. The group broadly breaks into B-lymphocytes and T-lymphocytes. <ref>{{MeSH}}</ref> | ||
The [[lymphocyte count]] is "the number of lymphocytes per unit volume of blood."<ref>{{MeSH|Lymphocyte count}}</ref> | The [[lymphocyte count]] is "the number of lymphocytes per unit volume of blood."<ref>{{MeSH|Lymphocyte count}}</ref> | ||
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Lymphocytes of these types directly destroy appropriate target cells, or help generate cells that do. | Lymphocytes of these types directly destroy appropriate target cells, or help generate cells that do. | ||
===T4 Helper Cells=== | ===T4 Helper Cells=== | ||
T-lymphocytes with the T4 protein on their surface which recognizes the antigenic peptide while the CD4 molecule recognizes the [[major histocompatibility complex]] (MHC-II) molecule. These "helper T-lymphocytes" cause the production of more cells for cell-mediated immunity, but they first must be activated by [[cytokine]]s, such as [[interleukin#interleukin I|interleukin | T-lymphocytes with the T4 protein on their surface which recognizes the antigenic peptide while the CD4 molecule recognizes the [[major histocompatibility complex]] (MHC-II) molecule. These "helper T-lymphocytes" cause the production of more cells for cell-mediated immunity, but they first must be activated by [[cytokine]]s, such as [[interleukin#interleukin I|interleukin-1]] (Il-I).<ref name=>{{citation | ||
| contribution = T4 -Lymphocytes (T4-Cells; T4-Helper Cells; CD4+ Cells) | | contribution = T4 -Lymphocytes (T4-Cells; T4-Helper Cells; CD4+ Cells) | ||
| title = The adaptive immune system: I. Introduction, B. Major cells and key cell-surface molecules involved in adaptive immune responses | | title = The adaptive immune system: I. Introduction, B. Major cells and key cell-surface molecules involved in adaptive immune responses | ||
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As well as being invoked by cytokines, they generate cytokines: | As well as being invoked by cytokines, they generate cytokines: | ||
*[[ | *[[Interleukin-2]] (Il2) | ||
*[[ | *[[Interleukin-3]] | ||
*[[Tumor necrosis factor alpha]] (TNFa) | *[[Tumor necrosis factor-alpha]] (TNFa) | ||
*[[B-cell growth factor]] (BCGF) | *[[B-cell growth factor]] (BCGF) | ||
*[[B-cell differentiation factor]] (BCDF) | *[[B-cell differentiation factor]] (BCDF) | ||
===T8 Killer cells=== | ===T8 Killer cells=== | ||
CD8-protein containing lymphocytes, also called T8-lymphocytes, are a subset of circulating "killer cells". All CD8-cells are killers, but other killer cells may be [[monocyte]]s, [[ | CD8-protein containing lymphocytes, also called T8-lymphocytes, are a subset of circulating "killer cells". All CD8-cells are killers, but other killer cells may be [[monocyte]]s, [[macrophage]]s (derived from [[monocyte]]s) or polynuclear [[neutrophil]]s. The key is that a killer cell attacks material labeled with the B-lymphocyte generated antibody. | ||
These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a [[graft-versus-host]] (GVH) reaction, or after immunization with an [[transplantation#allograft]], tumor cell or virally transformed or chemically modified target cell. The manner in which these cells destroy targets is sometimes called cell-mediated lympholysis (CML). | These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a [[graft-versus-host]] (GVH) reaction, or after immunization with an [[transplantation#allograft]], tumor cell or virally transformed or chemically modified target cell. The manner in which these cells destroy targets is sometimes called cell-mediated lympholysis (CML). | ||
==References== | ==References== | ||
{{reflist}} | {{reflist}}[[Category:Suggestion Bot Tag]] | ||
Latest revision as of 06:00, 14 September 2024
A lymphocyte is a type of leukocyte (i.e., white blood cell), which are a major component of the immune system. The group broadly breaks into B-lymphocytes and T-lymphocytes. [1]
The lymphocyte count is "the number of lymphocytes per unit volume of blood."[2]
B-lymphocyte
These are cells involved in the production of antibiodies (i.e., the humoral immune response. They have no relationships to the B- or Beta-cells of the pancreas.
T-lymphocyte
Lymphocytes of these types directly destroy appropriate target cells, or help generate cells that do.
T4 Helper Cells
T-lymphocytes with the T4 protein on their surface which recognizes the antigenic peptide while the CD4 molecule recognizes the major histocompatibility complex (MHC-II) molecule. These "helper T-lymphocytes" cause the production of more cells for cell-mediated immunity, but they first must be activated by cytokines, such as interleukin-1 (Il-I).[3]
As well as being invoked by cytokines, they generate cytokines:
- Interleukin-2 (Il2)
- Interleukin-3
- Tumor necrosis factor-alpha (TNFa)
- B-cell growth factor (BCGF)
- B-cell differentiation factor (BCDF)
T8 Killer cells
CD8-protein containing lymphocytes, also called T8-lymphocytes, are a subset of circulating "killer cells". All CD8-cells are killers, but other killer cells may be monocytes, macrophages (derived from monocytes) or polynuclear neutrophils. The key is that a killer cell attacks material labeled with the B-lymphocyte generated antibody.
These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an transplantation#allograft, tumor cell or virally transformed or chemically modified target cell. The manner in which these cells destroy targets is sometimes called cell-mediated lympholysis (CML).
References
- ↑ Anonymous (2024), Lymphocyte (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Anonymous (2024), Lymphocyte count (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Kaiser, Gary E., T4 -Lymphocytes (T4-Cells; T4-Helper Cells; CD4+ Cells), "The adaptive immune system: I. Introduction, B. Major cells and key cell-surface molecules involved in adaptive immune responses", Doc Kaiser's Microbiology Home Page