Search results
Results from the WOW.Com Content Network
Like macrophages, intestinal macrophages are differentiated monocytes, though intestinal macrophages have to coexist with the microbiome in the intestines. This is a challenge considering the bacteria found in the gut are not recognized as "self" and could be potential targets for phagocytosis by the macrophage.
The gut-associated lymphoid tissue lies throughout the intestine, covering an area of approximately 260–300 m 2. [5] In order to increase the surface area for absorption, the intestinal mucosa is made up of finger-like projections (), covered by a monolayer of epithelial cells, which separates the GALT from the lumen intestine and its contents.
Intestinal macrophages have been shown to accelerate intestinal inflammation through inducing IL-22 production by mucosal ILC3. [24] ILC3 have been observed to trans-differentiate into IFN-γ-producing ILC1-like cells via IL-23 and IL-12 signalling under certain circumstances, leading to chronic inflammation. [24]
In immunology, the mononuclear phagocyte system or mononuclear phagocytic system (MPS) also known as the macrophage system is a part of the immune system that consists of the phagocytic cells [1] located in reticular connective tissue. The cells are primarily monocytes and macrophages, and they accumulate in lymph nodes and the spleen.
Macrophages are produced through the differentiation of monocytes, and after ingestion of bacteria, secrete enzymes to destroy the ingested particle. These cells reside in every tissue of the body, and upon infected tissue, are recruited to the tissue. Once recruited, macrophages will differentiate into specific tissue macrophages.
Alarm molecules released from epithelial cells activate immune cells. [ 17 ] [ 18 ] Dendritic cells and macrophages are activated in this environment and produce key pro-inflammatory cytokines such as IL-6 , IL-12 , and IL-23 which activate more immune cells and direct them towards a pro-inflammatory state. [ 18 ]
Innate lymphoid cells (ILCs) are the most recently discovered family of innate immune cells, derived from common lymphoid progenitors (CLPs). In response to pathogenic tissue damage, ILCs contribute to immunity via the secretion of signalling molecules, and the regulation of both innate and adaptive immune cells.
T helper cells (also known as effector T cells or T h cells), a sub-group of lymphocytes, are responsible for the activation of macrophages. T h 1 cells activate macrophages by signaling with IFN-gamma and displaying the protein CD40 ligand. [77] Other signals include TNF-alpha and lipopolysaccharides from bacteria. [75]