Blood Cells - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 147

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3.11.3 NKR LTi-like Cells - ILC22 Cells

ILC22 cells, also called NKR LTi-like cells, NK22 (NK-like cell that produce

large amounts of IL22), NCR22, and ILC22 cells, are mainly observed in the lamina
propria of the intestine, Peyer's patches, mesenteric lymph nodes, and palatine
tonsils.
In humans, they express CD56 (140-kDa isoform of neural cell adhesion
molecule) and natural cytotoxicity receptor NCR2, 141 but have low NCR1 142
expression [ 272 ]. These cells differ from conventional NK cells, as they are non-
cytotoxic, lack killer inhibitory receptors, and do not produce or only tiny amounts
of Ifn

+

. Human IL22-producing ILCs also synthesize CD117, or SCFR, and CD127,
or IL7R

γ

chain, as well as IL5 and IL13; in addition to IL22. Human ILC22 cells
isolated from tonsils secrete many cytokines, such as IL2, IL5, IL8, IL13, and TNF
agents. They also secrete large amounts of B-cell-activation factor; they may thus
contribute to the regulation of T-cell-independent antibody production.
Like LTi cells, ILC22 cells can induce expression of ICAM1 and VCAM1 on
mesenchymal stem cells in vitro [ 272 ]. Soluble IL23 can regulate IL22 production
by ILC22 cells in humans. Cytokines of the common

α

-chain family (IL2, IL7, and
IL15) can also activate the proliferation and cytokine production of human ILC22
cells.
In the adult small intestine, natural killer-like cells express ROR

γ

γ 2 (NR1f3-2)

and secrete IL22. Cells of the family of pro-inflammatory ROR γ 2 + innate lymphoid

cells differentiate from distinct fetal liver ROR γ 2 + precursors [ 274 ]. They develop

in the absence of microbiota.
T H2 -like innate lymphoid cells have multipotent progenitor capacity. They
generate mastocytes, basophils, and macrophages when stimulated by interleukin-
25 [ 274 ].

3.11.4 Nuocytes

Well-known leukocyte effectors of innate and adaptive immunity include T and
B cells, natural killer T cells, natural killer cells, dendritic cells, neutrophils,
eosinophils, mastocytes, basophils, and macrophages. Some types of innate im-
munocytes, such as basophils, eosinophils, and mastocytes, release type-2 cy-
tokines. Interleukin-25 (or IL17e) and IL33 activate the T H2 response. Type-2
immunity reacts to parasitic infections. In particular, IL13 cytokine mediates host
response to helminth intruders and allergy. Type-2 cytokines cause eosinophilia,
goblet cell hyperplasia, mucus secretion, and IgE production.

141 A.k.a. natural killer cell P44 protein (NKp44).
142 A.k.a. NKp46.