Blood Cells - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 143

coadministrated with intranasal vaccine stimulates NK-cell migration in these
lymphoid tissues and promotes protective mucosal immunity against influenza
viruses [ 270 ]. 135

3.11 Innate Lymphocytes

Innate lymphoid cells (ILC) characterized by a prompt delivery of their effector
functions constitute a set of developmentally related cells, such as natural killer
(NK) and lymphoid tissue-inducer (LTi) cells as well as cells that produce inter-
leukins IL5, IL13, IL17, and/or IL22, such as ILC22 cells 136 and nuocytes [ 272 ]. 137
ILC17(orLTi)andILC22(NKR LTi-like) cells produce interleukin-17 and/or -

22; ILC2 cells, or nuocytes, synthesize IL5 and IL13 agents.
Different ILC cell types was grouped into 3 main subsets: natural killer,
natural helper, and NR1f3-2

+

) cells (Table 3.36 ). The
IL15-dependent NK category includes: (1) conventional NK (cNK) CD16

+ (ROR γ 2 + or ROR γ T +

− and

,CD56 high , CD16 + cells, which have spontaneous cytotoxicity, and (2) Ifn γ+

cell subset, which includes a cytokine-polarized subset of CD56 high

CD16 − cells

in humans [ 272 ]. ILC cells depend on cytokines that use the common chain of the

receptors for IL2, IL4, IL7, IL9, IL15, and IL21. Different ILC subsets need distinct
members of this cytokine set (Table 3.36 ).
These hematopoietic effectors operate in innate immune responses to microor-
ganisms as well as in lymphoid tissue formation, in tissue remodeling after damage
by injury or infection, and in stromal cell homeostasis. In particular, NK cells
limit the propogation of viruses before the initiation of the adaptive immune
response [ 272 ]. NK cells recognize pathogen ligands using specific receptors
and eliminate infected or stressed cells using perforin- and granzyme-containing
cytotoxic granules, TNFSF1, TNFSF6, TNFSF10, and interferon-

γ

γ .

135 NKT cells colocalize and interact with dendritic cells that have taken up and store

-galactosyl
ceramide. The flux of NKT cells to nasopharynx-associated lymphoid tissue and regional cervical
lymph nodes is mediated by CXC-chemokine receptor CXCR6 of NKT cells. Accumulation
of NKT cells in nasopharynx-associated lymphoid tissue and regional cervical lymph nodes
stimulates IgA production by a mechanism that depends on interleukin-4. Molecule IgA is
the most abundant antibody in the intestinal mucosa, where it provides immune protection
against commensal bacteria and ingested pathogens. B lymphocytes produce IgA after undergoing
class-switch recombination [ 271 ]. B lymphocytes undergo IgA class switching through both T-
cell-dependent and T-cell-independent stimulations, which generate high- and low-affinity IgA
antibodies, respectively. T-cell-dependent IgA class switching in the germinal centers of gut
organized lymphoid structures requires T-cell help for B cells via TNFSF5 and transforming growth
factor-

α

β

1. T-cell-independent IgA class switching in non-organized lymphoid tissue of the lamina
propria involves microbial Toll-like receptor ligands and TNFSF5-related dendritic cell mediators
(B-cell-activating factor and proliferation-inducing ligand).
136 A.k.a. NK22 cells, natural cytotoxicity receptor-22 (NCR22) cells, and NK receptor NKR +
LTi-like cells.
137 A.k.a. natural helper (NH) cells.