Cell-mediated immunity

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Cellular immunity
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Immunofluorescence micrograph of three cytotoxic T cells (outer three) surrounding a cancer cell. Lytic granules (red) are secreted at the contact site, killing the target. Cytotoxic T cells are powerful agents of cellular immunity.

Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies. Rather, cell-mediated immunity is the activation of

cytokines in response to an antigen.[1]

History

In the late 19th century

antibodies.[1]

In another ideology, the

NK cells) and intraepithelial lymphocytes.[2]

Synopsis

Cellular immunity protects the body through:

Cell-mediated immunity is directed primarily at

protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection
.

Type 1 immunity is directed primarily at

TNF.[citation needed
]

Overview

CD4+

T-helper cells may be differentiated into two main categories:[5]

  1. TH1 cells which produce interferon gamma and lymphotoxin alpha,
  2. TH2 cells which produce IL-4, IL-5, and IL-13.

A third category called T helper 17 cells (TH17) were also discovered which are named after their secretion of Interleukin 17.

CD8+

cytotoxic T-cells may also be categorized as:[5]

  1. Tc1 cells,
  2. Tc2 cells.

Similarly to CD4+ TH cells, a third category called TC17 were discovered that also secrete IL-17.

As for the ILCs, they[Clarification needed.] may be classified into three main categories[5]

  1. ILC1 which secrete type 1 cytokines,
  2. ILC2 which secrete type 2 cytokines,
  3. ILC3
    which secrete type 17 cytokines.

Development of cells

All type 1 cells begin their development from the

common lymphoid progenitor (CLp) which then differentiates to become the common innate lymphoid progenitor (CILp) and the t-cell progenitor (Tp) through the process of lymphopoiesis.[5][6]

Common innate lymphoid progenitors may then be differentiated into a natural killer progenitor (NKp) or a common helper like innate lymphoid progenitor (CHILp). NKp cells may then be induced to differentiate into

ILC3 cells by IL-7 as well.[5][6]

T-cell progenitors may differentiate into naïve CD8+ cells or naïve CD4+ cells. Naïve CD8+ cells may then further differentiate into TC1 cells upon

IL-1 or IL-23 exposure.[5][6]

Type 1 immunity

Type 1 immunity makes use of the type 1 subset for each of these cell types. By secreting

viruses. It is also responsible for inflammation and autoimmunity with diseases such as rheumatoid arthritis, multiple sclerosis, and inflammatory bowel disease all being implicated in type 1 immunity. Type 1 immunity consists of these cells:[5]

CD4+ TH1 Cells

It has been found in both

tight junctions in the epithelial barrier.[5]

CD8+ TC1 Cells

These cells generally produce

T-bet activation is required for both interferon gamma and cytolytic potential. CCR5 and CXCR3 are the main chemokine receptors for this cell.[5]

Group 1 ILCs

Groups 1 ILCs are defined to include

GM-CSF and IL-2 in response to cytokine stimulation but have low or no cytotoxic ability.[5]

See also

References

  1. ^
    S2CID 52915054
    .
  2. S2CID 35251844
    .
  3. ^ a b Eissmann, Philipp. "Natural Killer Cells". British Society for Immunology. Retrieved 8 November 2018.
  4. ^ a b Saldana, José. "Macrophages". British Society for Immunology. Retrieved 8 November 2018.
  5. ^
    PMID 25528359
    .
  6. ^
    PMID 30804475
    .

Bibliography

Further reading

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