Includes different T cell subtypes, it's role, function, cytokines involved in activation and the mechanisms of action
T cell subtypes: CD4 Th, CD4 Th1, CD4 Th2, CD4 TH17, Tfh, CD8 Tc, CD4 Treg
❖ T cell cellular immunity:
T cell subsets Overall Role Function Cytokines involved Mechanism
CD4 TH Activates & Stimulates components of adaptive & • Has TCR - recognises MHC II on B cells, body cells
regulates innate immunity
immune
response
CD4 TH1 Cell mediated Activates macrophages IFN-γ • Increases phagocytosis, microbicidal killing, prod of cytokines
immune (TNFα, IL1)
response Activates Tc cells IL2, IFN-γ, TNF • Prolif and diff into effector TC cells to kill target cells expressing
specific antigen
CD4 TH2 Parasite & Mast cell activation IL3, IL9 • Granule release and recruits inflammatory cells
allergen defence Eosinophils recruitment & activation IL5 • Granule release, causes parasite killing
IgE production IL4 • B cell class switching - IgE arms mast cells & eosinophils
Tissue repair and mucosal immunity IL13 • Promotes goblet/epithelial cell proliferation & mucus secretion
CD4 TH17 Bacterial & Activate neutrophils IL17 • Activates myeloid and stromal to produce G-CSF and IL8
fungal defence • Neutrophil recruitment and activation
• Granule release to kill bacteria
TFH B cell Helps B cells make specific Ab via • B7-CD28 & CD40-CD40L → creates larger Ab response
differentiation linked recognition of TCR & MHC IL4, IL21 • Cytokine release - signal prolif and diff of B cells → plasma cells
and Ab prod epitope IL4, IL21 • Essential for class switching, somatic hypermutation*,
IL6, IL21 memory cell differentiation
CD8 TC Killing infected Kills cells expressing specific antigen • Granzyme/perforin - perforation, granzymes enter
host cells Recognises MHC I • FasL/Fas - (FasL on TC)
• Both leads to caspase signalling → apoptosis
CD4 Treg Suppression and Suppresses activation and prolif of T IL10, TGFβ • CTLA4 protein receptor, binds to B7 co-stim mol on APC, blocks
Tolerance cells B7-CD28 interactions
Use of CTLA-4 to modify APC • Deprives other T cells of IL2 for activation and proliferation
Binds and consumes IL2 via CD25
*Somatic hypermutation - process undergoing random mutations resulting in the production of an Ab with increased affinity for a specific Ag
I^MD Page 1
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller dan001. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $6.49. You're not tied to anything after your purchase.
