Basophil mast cell similarities

There are also other immimological mechanisms, especially via IgG or IgM antibodies with immune complex formation, which can lead to similar clinical conditions [20, 34, 42] as has been shown in dextran anaphylaxis (table 1). Triggering of mast cells and basophils leads to release of various vasoactive mediators, among which histamine was the first recognized in 1908 (fig. 3,4) [6]. 

In spite of the above-mentioned similarities between basophils and mast cells, they differ in many other aspects [1,2]. Basophils complete their differentiation within the bone marrow, and mature basophils circulate in the peripheral blood and do not usually infiltrate into peripheral tissues unless inflammation takes place. Mast cells originate from hematopoietic cells in the bone marrow as do basophils, but they mature in peripheral tissues after their bone marrow-derived precursors enter the circulation and migrate into peripheral tissues. Mature mast cells reside in peripheral tissues and do not usually circulate in the peripheral blood. The lifespan of basophils is very short (several days), in contrast to that of mast cells (weeks to months). Basophils do not proliferate once they terminally differentiate whereas mature mast cells keep potential to expand in response to various stimuli. These differences between basophils and mast cells, including distinct anatomical localization, suggest their differential roles in vivo. 

Basophils are the least abundant of the leukocytes and account for less than 1% of the total number of white blood cells. They are similar structurally and functionally to the mast cells found in connective tissues, especially in the lungs, skin, and gastrointestinal tract. Basophils and mast cells play an important role in allergic reactions. The granules of these cells contain many substances, including ... 

Somatostatin (SOM), initially identified by its ability to inhibit the release of growth hormone, is known to have inhibitory effects on a variety of cells [ 109], In mast cells and in basophils, SOM, like NT, has inhibitory as well as stimulatory effects depending on the concentration used. At high concentrations (> 10 8 M), SOM is a powerful stimulus of peritoneal mast-cell secretion (from both normal and athymic rats) and resembles other non-immunologic secretagogues such as compound 48/80, SP and NT in that it triggers a rapid exocytosis that is primarily dependent on cellular Ca [ 110,111], A similar effect is seen in vivo when injected into skin or skin blisters at high concentrations (> 10-8 M), SOM causes a rapid, dose-dependent release of histamine [88, 112] but when used at concentrations lower than those which elicit a secretory... 

Procaine, on the other hand, is an ester-type local anesthetic when it is injected into the organism, it is transformed into N,N-diethylaminoethanol and para-amino-benzoic acid (PABA) when the ester link that binds these two components of procaine is broken. PABA is a well-known allergen. Methyl para-hydroxybenzoate, whose structure is similar to that of PABA, is also called PAB or methylparaben. It is a preservative that binds, like a hapten, to the immunoglobulin E (IgE) on the surface of mast cells and basophils and maybe the cause of the few cases of anaphylactic shock that have been described. Other patients may be allergic to metabisulfite conservative, found in preparations containing adrenaline (epinephrine). 

IL-13, IL-4, and IL-5 together belong to the family of Th2 c3d okines and share similar bio-logical activities on human B-cells and mono-Qites (545). IL-13 is a 17-kDa glycoprotein pri-Imarily produced by Th2 cells and, to a lesser lextent, hy macrophages, dendritic cells, NK cells, mast cells, and basophils. 

The relationship between protein Fv and IgE was investigated by performing cross-desensitization between these two stimuli [32, 41], Human basophils and mast cells preincubated with protein Fv released approximately 90% less histamine when challenged with anti-IgE. Similarly, when protein Fv-pretreated... 

Basophils are the least numerous and least well characterized of the circulating leukocytes. While they are not derived from the same progenitor cell as tissue mast cells, basophils and mast cells have several similar functions, including their participation in hypersensitivity reactions. Basophils have also been attributed roles in plasma lipolysis, parasite immunity, tumor cell cytotoxicity, and hemostasis. Increases have been associated with persistent lipemia, parasitism, allergic diseases, certain neoplastic diseases, and administration of certain drugs (e.g., heparin, penicillin). 

Some venoms, such as that of the wasp, contain potent histamine-releasing peptides. Since basic polypeptides are released on tissue injury, they constitute pathophysiological stimuli to secretion for mast cells and basophils. Anaphylatoxins (C3a and C5a), which are low-molecular-weight peptides released during activation of complement, may act similarly. 

The current descriptions of sensitivity and maximal response are best applied to secretion of histamine. However, a more complete understanding will require further information about the same parameters in the context of lipid and cytokine release. Both of these mediators are critical determinants of the allergic inflammatory response, so that understanding the extent to which new therapeutics need to suppress basophil and mast cell responsiveness will be dependent on new information regarding the relative roles of each of the secreted mediators. Recent studies have indicated that basophil sensitivity is very similar when viewed from the secretion of each of three classes of mediators. This means that if cell surface antigen-specific IgE is present at a density sufficient to initiate only 50% of the maximum histamine release, approximately 50% of the maximal secretion of IL-4 and LTC4 will also be obtained. It remains to be determined whether the equivalent suppression of secretion for each of the three classes of mediators will lead to equivalent reductions for the functional endpoints of the three different mediator classes. 

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