Gut-Associated Lymphoid Tissues (GALTs)

Naive and memory B cells encounter antigens that are transported into the structure by M cells. When an antigen-specific naive or memory B-cell encounters an antigen via its BCR, it is activated. After activation, antigen-specific B cells proliferate within the subepithelial dome.
Bemark et al. 2024 J Immunol 45(3): 211

The GI mucosa is considered the biggest human lymphoid organ.
Bilinski et al. 2022 Biomedicines 10: 837

Gut-associated, lymphoid tissue (MALT and GALT ) contains about 70% of the lymphocyte population, and there is constant, never-ending “conversation” between immune-competent cells and the microbiota.
Jung et al. 2010 Int J Inflam. 2010:823710
Bilinski et al. 2022 Biomedicines 10: 837

Gut-Associated Lymphoid Tissues (GALTs) = Lymphoid Tissues / Lymphatic System associated with the Intestine, comprising Peyer's Patches (PPs), the appendix, and Isolated Lymphoid Follicles (ILFs) in the intestinal wall, where adaptive immune responses are initiated
Murphy 2022 W.W. Norton & Company ISBN 978-0-393-68093-5

The Gut-Associated Lymphoid Tissues (GALTs) , which prevents the gut microbes from invading GI mucosa, is normally innervated and suppressed by the sympathetic nervous system
Willman et al. 2022 Clin. Transl. Disc. 2: e139

Chemokine (C-X-C motif) ligand 8 (CXCL8) / Interleukin-8 (IL-8), cytokines (Interleukin-1 (IL-1) / Interleukin-1 family, Interleukin-6 (IL-6), Interleukin-7 (IL-7), Interleukin-11 (IL-11), and TNF), and growth factors (Stem Cell Factor (SCF) and G-CSF) released from enterocytes will recruit peripheral neutrophils and mast cells to intestinal subepithelial regions and accelerate activation and differentiation of local lymphocytes. Interleukin-7 (IL-7) and Stem Cell Factor (SCF), secreted by intestinal epithelial cells, can work together to activate TCRgamma/delta+ IELs
Zhang et al. 2019l

The gut-associated lymphoid tissue consists of the epithelium, lamina propria, and muscular layer.
Brown et al. 2013 Nature Immunology 14(7): 660-667

Gut microbiota is required for the normal generation and/or maturation of Gut-Associated Lymphoid Tissues (GALTs). In Gut-Associated Lymphoid Tissues (GALTs) antigen can be taken up and presented by antigen presenting cells
Kamada et al. 2013 Nature Rev. Immunol. 13: 321

Gut-associated lymphatic tissue (GALT ), which mainly consists of Peyer's Patches (PPs) and Isolated Lymphoid follicles (ILFs), act as inductive sites in the intestine, while mesenteric lymph nodes (MLN) empty the intestine (= inductive sites). Peyer patches (PP) are supported by blood and lymph vessels that enable B (naive and memory B cells ) and T cells to penetrate areas between the B cell follicles via high endothelial venules

Yamaguchi & Schoefl 1983 Anat Rec. 206: 391-401
Azzali 2003 Immunol Rev. 195: 178-189
Ma et al. 2007 Anat Histol Embryol 36: 62-74).

B cells have also been detected in the epithelium, where they show expression of Fc receptor-like 4 (FcRL4)
Spencer et al. 1985 Clin. Exp. Immunol. 62: 607-612
Falini et al. 2003 Blood 102: 3684-3692

The gut-associated lymphoid tissue (GALT ) makes the gastrointestinal tract the largest Lymphoid Tissues / Lymphatic System or immune organ in the human body
Collins et al. 1998 Int. Dairy Journal 8: 487-490

Gut-Associated Lymphoid Tissues (GALTs) is accounting for approximately 80% of all Antibodies / Immunoglobulins-producing cvlls in the body
Targan & Shanahan 1994 Williams & Wilkins, Baltimore, USA.

see also:
Gut microbiota & Immunity
Immune Cells / Leucocytes / White Blood Cells & Intestine / Gastrointestinal Tract (Gut / GIT)