Editing Mast cell (section)

==Structure==
[[File:Blausen 0018 Anaphylaxis.png|thumb|Illustration depicting mast cell activation and anaphylaxis]]
[[Image:Mast cell.png|thumb|Mast cell]]

Mast cells are very similar to [[basophil granulocyte]]s (a class of [[white blood cell]]s) in [[blood]], in the sense that both are [[granulocyte|granulated cells]] that contain [[histamine]] and [[heparin]], an [[anticoagulant]]. Their [[cell nucleus|nuclei]] differ in that the basophil nucleus is [[lobation|lobated]] while the mast cell nucleus is round. The [[Fragment crystallizable region|Fc region]] of [[immunoglobulin E]] (IgE) becomes bound to mast cells and basophils, and when IgE's [[paratope]]s bind to an antigen, it causes the cells to release histamine and other inflammatory mediators.<ref name="Marieb, Elaine N. 2007. pg. 659">{{cite book | title = Human Anatomy and Physiology | last1 = Marieb | first1 = Elaine N. | last2 = Hoehn | first2 = Katja | name-list-style = vanc | publisher = Pearson Benjamin Cummings | year = 2004 | isbn = 978-0-321-20413-4 | edition = 6th | location = San Francisco | page = [https://archive.org/details/humananatomyphys0006mari/page/805 805] | url = https://archive.org/details/humananatomyphys0006mari/page/805 }}</ref> These similarities have led many to speculate that mast cells are basophils that have "homed in" on tissues. Furthermore, they share a common precursor in [[bone marrow]] expressing the [[CD34]] molecule. Basophils leave the bone marrow already mature, whereas the mast cell circulates in an immature form, only maturing once in a tissue site. The site an immature mast cell settles in probably determines its precise characteristics.<ref name=Prussin>{{cite journal |vauthors=Prussin C, Metcalfe DD |title=4. IgE, mast cells, basophils, and eosinophils |journal=The Journal of Allergy and Clinical Immunology |volume=111 |issue=2 Suppl |pages=S486–94 |date=February 2003  |pmid=12592295 |doi=10.1067/mai.2003.120|pmc=2847274 }}</ref> The first ''in vitro'' differentiation and growth of a pure population of mouse mast cells was carried out using conditioned medium derived from concanavalin A-stimulated splenocytes.<ref name="pmid6166010">{{cite journal |author1=Razin E |author2=Cordon-Cardo C |author2-link=Carlos Cordon-Cardo |author3=Good RA |title=Growth of a pure population of mouse mast cells in vitro with conditioned medium derived from concanavalin A-stimulated splenocytes |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=78 |issue=4 |pages=2559–61 |date=April 1981  |pmid=6166010 |pmc=319388 |doi=10.1073/pnas.78.4.2559|bibcode=1981PNAS...78.2559R |doi-access=free }}</ref> Later, it was discovered that T cell-derived [[interleukin 3]] was the component present in the conditioned media that was required for mast cell differentiation and growth.<ref name="pmid6198393">{{cite journal |vauthors=Razin E, Ihle JN, Seldin D, etal |title=Interleukin 3: A differentiation and growth factor for the mouse mast cell that contains chondroitin sulfate E proteoglycan |journal=Journal of Immunology |volume=132 |issue=3 |pages=1479–86 |date=March 1984 |doi=10.4049/jimmunol.132.3.1479 |pmid=6198393 |s2cid=22811807 |doi-access=free }}</ref>

Mast cells in rodents are classically divided into two subtypes: [[connective tissue]]-type mast cells and [[mucosa]]l mast cells. The activities of the latter are dependent on [[T-cell]]s.<ref name="Denburg_1998">{{cite book | last = Denburg | first = Judah A. | name-list-style =vanc | title = Allergy and allergic diseases: the new mechanisms and therapeutics | publisher = Humana Press | location = Totowa, NJ | year = 1998 | isbn = 978-0-89603-404-4 }}{{page needed|date=April 2014}}</ref>

Mast cells are present in most tissues characteristically surrounding blood vessels, nerves and lymphatic vessels,<ref>{{cite journal |title=Histamine-mediated autocrine signaling in mesenteric perilymphatic mast cells |journal= American Journal of Physiology. Regulatory, Integrative and Comparative Physiology |volume=318 |issue=3 |pages=R590-604 |date=March 2020  |doi= 10.1152/ajpregu.00255.2019 |pmid=31913658 |last1= Pal |first1= Sarit |last2= Gasheva |first2= Olga Y. |last3= Zawieja |first3= David C. |last4= Meininger |first4= Cynthia J. |last5= Gashev |first5= Anatoliy A. |pmc= 7099465 }}</ref> and are especially prominent near the boundaries between the outside world and the internal milieu, such as the [[skin]], mucosa of the [[lung]]s, and [[digestive tract]], as well as the [[mouth]], [[conjunctiva]], and [[Human nose|nose]].<ref name=Prussin/>