Editing T cell (section)

====Helper CD4<sup>+</sup> T cells====
{{Main|T helper cell}}
[[File:CD4+ T cell subsets.pdf|thumb|Depiction of the various key subsets of CD4-positive T cells with corresponding associated cytokines and transcription factors.]]

[[T helper cell]]s (T<sub>H</sub> cells) assist other lymphocytes, including the maturation of [[B cell]]s into [[plasma cell]]s and [[memory B cell]]s, and activation of [[cytotoxic T cells]] and [[macrophage]]s. These cells are also known as '''CD4<sup>+</sup> T cells''' as they express the [[CD4]] glycoprotein on their surfaces. Helper T cells become activated when they are presented with [[peptide]] [[antigen]]s by [[MHC class II]] molecules, which are expressed on the surface of [[antigen-presenting cell]]s (APCs). Once activated, they divide rapidly and secrete [[cytokine]]s that regulate or assist the immune response. These cells can differentiate into one of several subtypes, which have different roles. Cytokines direct T cells into particular subtypes.<ref name="pmid17476341">{{cite journal|vauthors=Gutcher I, Becher B|title = APC-derived cytokines and T cell polarization in autoimmune inflammation|journal = J. Clin. Invest.|volume = 117|issue = 5|pages = 1119–27|year = 2007|pmid = 17476341|pmc = 1857272|doi = 10.1172/JCI31720}}</ref>

{|class="wikitable"
|+CD4<sup>+</sup> helper T cell subsets
!Cell type!!Cytokines Produced!!Key Transcription Factor!!Role in immune defense!!Related diseases
|-
|[[Th1 cell|Th1]]||[[IFNγ]], IL-2||[[TBX21|Tbet]]||Produce an inflammatory response, key for defense against intracellular bacteria, viruses and cancer.||MS, Type 1 diabetes
|-
|[[Th2]]||IL-4, IL-5, IL-13||GATA-3||Immunologically important against extracellular pathogens, such as worm infections||Asthma and other allergic diseases

|-
|[[Th17]]||IL-17F, IL-17A, IL-22||RORγt||Defense against gut pathogens and at mucosal barriers||MS, Rheumatoid Arthritis, Psoriasis
|-
|[[Th 9 cell|Th9]]<ref>{{cite journal|vauthors = Wang W, Sung N, Gilman-Sachs A, Kwak-Kim J|title = T Helper (Th) Cell Profiles in Pregnancy and Recurrent Pregnancy Losses: Th1/Th2/Th9/Th17/Th22/Tfh Cells|journal = Frontiers in Immunology|volume = 11|pages = 2025|date = 18 August 2020|pmid = 32973809|pmc = 7461801|doi = 10.3389/fimmu.2020.02025|doi-access = free}}</ref><ref name="Saravia 634–643">{{cite journal|vauthors = Saravia J, Chapman NM, Chi H|title = Helper T cell differentiation|journal = Cellular & Molecular Immunology|volume = 16|issue = 7|pages = 634–643|date = July 2019|pmid = 30867582|pmc = 6804569|doi = 10.1038/s41423-019-0220-6}}</ref>||IL-9||IRF4, PU.1||Defense against helminths (parasitic worms) and cell-dependent allergic inflammation||Multiple Sclerosis
|-

|[[Follicular B helper T cells|Tfh]]||IL-21, IL-4||Bcl-6||Help B cells produce antibodies||Asthma and other allergic diseases
|-
|Th22<ref>{{cite book|vauthors = Jia L, Wu C| title=T Helper Cell Differentiation and Their Function | chapter=The Biology and Functions of Th22 Cells | series=Advances in Experimental Medicine and Biology |volume = 841|pages = 209–230|year = 2014|pmid = 25261209|doi = 10.1007/978-94-017-9487-9_8|isbn = 978-94-017-9486-2}}</ref><ref name="Saravia 634–643"/>
|IL-22
|AHR
|Pathogenesis of allergic airway diseases and predominantly anti-inflammatory
|Crohn's Disease, Rheumatoid Arthritis, Tumors
|}