What cell secretes IgA?
What cell secretes IgA?
Secretory IgA is composed of two IgA molecules (dimeric IgA), a joining protein (J chain), and a secretory component. The dimeric IgA-J chain complex is produced by B lymphocytes in the submucosal tissues. The secretory component is produced by mucosal epithelial cells and acts as a receptor for dimeric IgA.
Where is IgA secreted?
IgA subclasses differ in distribution and function. IgA1 is present mainly in the serum (it accounts for 85 per cent of serum IgA) and predominates in secretion in the upper intestine and in the various mucosal glands. IgA2 predominates in secretion in the large intestine and in the female genital tract.
Why is IgA important for gut immunity?
To maintain a peaceful bacteria-host interaction, the gut mucosa releases anti-microbial proteins and immunoglobulin A (IgA), an antibody isotype specialized in mucosal protection (2, 3). Anti-microbial proteins and IgA constrain the topography, composition, and pro-inflammatory activity of commensal bacteria (4).
How does IgA work in the gut?
Under homeostatic conditions, immunoglobulin A (IgA) is the major immunoglobulin isotype in the intestinal mucosa. Microbes stimulate the production of IgA, which controls bacterial translocation and neutralizes bacterial toxins at the intestinal mucosal surface.
Do plasma cells secrete IgA?
The intestinal mucosa harbors the largest population of antibody (Ab)-secreting plasma cells (PC) in the human body, producing daily several grams of immunoglobulin A (IgA).
Do B cells produce IgA?
The majority of activated B cells differentiate into IgA plasma cells, with the gut being the largest producer of immunoglobulin in the body. Secretory IgA antibodies have numerous critical functions of which protection against infections and the role for establishing a healthy microbiota appear most important.
What causes high secretory IgA in stool?
What does it mean if your Fecal secretory IgA result is too high? – High levels of Secretory IgA might reflect an activated immune response to chronic infections including viral infections such as EBV (Epstein–Barr virus), CMV (Cytomegalovirus), HIV, and/ or inflammatory reactions.
How are IgA antibodies secreted?
Secretory IgA Polymeric IgA (mainly the secretory dimer) is produced by plasma cells in the lamina propria adjacent to mucosal surfaces. It binds to the pIgR on the basolateral surface of epithelial cells, and is taken up into the cell via endocytosis.
How is mucosal IgA produced?
What is the difference between IgA and sIgA?
Immunoglobulin A (IgA, also referred to as sIgA in its secretory form) is an antibody that plays a crucial role in the immune function of mucous membranes. The amount of IgA produced in association with mucosal membranes is greater than all other types of antibody combined.
Where are IGA cells found in the human body?
In humans and mice, ~80% of the total plasma cells in the body are located in the intestinal mucosa, where they secrete dimeric IgA under steady-state conditions (40–60 mg/kg/day or 3–5 g/day in human) ( 3, 4 ). Interestingly, circulating IgA is mainly monomeric in humans, but largely oligomeric, composed of 2–4 monomers, in mice.
What is the function of IgA in the intestinal mucosa?
The intestinal mucosa is a physiological barrier for most microbes, including both commensal bacteria and invading pathogens. Under homeostatic conditions, immunoglobulin A (IgA) is the major immunoglobulin isotype in the intestinal mucosa.
What are IGA + plasmablasts and plasma cells?
These plasmablasts express somatically hypermutated V H gene rearrangements and spontaneously secrete IgA, exhibiting binding to microbial antigens. Notably, IgA + plasmablasts and plasma cells were identified in the lamina propria of patients treated with rituximab during peripheral B-cell depletion.
How does Iga affect the composition of commensal bacteria?
Mice that lack secretory IgA exhibits biased composition of commensal bacteria, known as dysbiosis, suggesting that IgA regulates the absolute number and diversity of the commensal bacteria through their growth inhibition and elimination ( 7 – 9 ).