Category Archives: Immune Cells
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Natural Killer (NK) Cells
Mast Cells
The immunological response of the body is orchestrated in large part by mast cells, which are a specialised type of white blood cell. When mast cells are activated, they release a number of mediators, including histamine, that can cause a variety of symptoms.
Although mast cells are present in every tissue in the body, they are most numerous in the lungs, skin, and gastrointestinal tract. Even though they are a component of the immune system, they are also capable of playing a role in allergic reactions.
Mast cells are found in tissues and have a function that is analogous to that of basophils, which circulate in the blood. Because of this, mast cells play a significant part in the production of protective acute inflammatory responses, and they are the origin of type I hypersensitivity reactions that are associated with atopic allergy.
The type I hypersensitivity reactions that are linked with atopic allergy originate in the basophils and mast cells of the immune system.
This means that when these cells are activated, they can release a number of mediators that can cause a variety of symptoms.
The most common way for mast cells to be activated is through cross-linking of IgE receptors. This occurs when allergens bind to the surface-attached IgE antibodies on mast cells.
Another way for mast cells to be activated is through the anaphylatoxin complement fragments C3a and C5a. These fragments are released when certain bacteria or viruses rupture cells. They can then bind to receptors on mast cells, which triggers degranulation.
What are the roles of tryptase and chondroitin sulfate in mast cell activation?
Tryptase is a protease that is released by mast cells when they are activated. It plays a role in the inflammatory response by digesting proteins in the extracellular matrix. Chondroitin sulfate is a glycosaminoglycan that is found in mast cell granules. It helps to regulate inflammation by inhibiting the action of proteases like tryptase.
By releasing these mediators, mast cells play a key role in causing protective acute inflammatory responses. Basophils and mast cells are the source of type I hypersensitivity reactions that are linked to atopic allergy. Cross-linking of IgE receptors or the anaphylatoxin fragments C3a and C5a can start the process of degranulation.
What is the role of diet in mast cell activation?
There are a number of ways to reduce mast cell activation and Inflammation. These include avoiding triggers, such as certain foods or environmental irritants, and following an antiinflammatory diet.
Diet can play a role in mast cell activation. Certain foods, such as dairy and wheat, can trigger an inflammatory response. Other foods, such as omega-3 fatty acids, can help to reduce inflammation.
T cells
B cells
B cells are a type of white blood cell that play a crucial role in the body’s immune system. There are two main types of B cells: naïve B cells and memory B cells. Naïve B cells are created in the bone marrow and have never been exposed to an antigen, while memory B cells are created in response to an antigen and can remember it for a long time.
B cells are important for the development of immunity against infection. They produce antibodies, which are proteins that help fight infection. When a foreign antigen is encountered, B cells produce specific antibodies that bind to the antigen and help destroy it.
B cells can also play a role in autoimmunity. In autoimmune diseases, the body’s own immune system attacks its own tissues. There is evidence that B cells can contribute to the development of autoimmune diseases by producing antibodies that target the body’s own tissues.
B cells make up between 5 and 15% of the lymphocytes that are found in the blood; they are also found in the bone marrow, the spleen, the lymph nodes, and the mucosa-associated lymphoid tissues.
B cells can present antigen to T cells and release cytokines, but their primary function is to develop into plasma cells, which manufacture and secrete antibodies.
The primary purpose of B cells is to grow into plasma cells, which are responsible for the production and secretion of antibodies. B cells can also release cytokines and present antigen to T cells.
The two stages of B cell response to antigen
Primary immune response:
When mature, naive B cells are exposed to antigen for the first time, they transform into lymphoblasts, go through clonal proliferation, and differentiate into memory cells. These memory record the instructions which enable the cell to react to the same antigen in the future, or develop into mature plasma cells that secrete antibodies.
This is known as the primary immune response.
There are several days of inactivity after an initial exposure to an antigen before the production of antibodies begins. After this point, only IgM will be generated.
Following this, with the assistance of T cells, B cells are able to perform additional rearrangement of their Ig genes and can then flip to the production of IgG, IgA, or IgE.
Because of this, the immune response following the first exposure is sluggish and initially only provides minimal protection.
The secondary immune response, also known as the anamnestic or booster reaction, occurs when memory B and Th cells are reexposed to the antigen. At this point, the memory B cells rapidly expand in number, develop into mature plasma cells, and release huge quantities of antibody (chiefly IgG because of a T cell–induced isotype switch). After being secreted into the blood and other tissues, the antibody is now in a position to interact with the offending antigen. Therefore, the immune response is both quicker and more effective after being reexposed to the pathogen.