Lecture notes Cells and Immunity T-Cell Phenotypes (BI2BC45)
2 views 0 purchase
Course
Cells and Immunity (BI2BC45)
Institution
University Of Reading (UoR)
The thirteenth lecture in a series for the module Cells and Immunity. This lecture covers T-Cell pheotypes, MHC complexes, T-helper cells, helper cells and more. A great way to start your understanding of the module or to miss a lecture or two.
L13 – T cell phenotypes
Lecture:
MHC complex
o Binds peptide fragments from pathogens to display to T cells (expressed on
antigen presenting cells)
o MHC class I presents to CD8 (cytotoxic cells)
o MHC Class II presents to CH4 (T helper cells)
o T cell receptor
Heterodimer (alpha and beta polypeptide chains)
Variable and constant region
Relies on CD3 non-covalently for signal transduction
5 types of polypeptides associate to 3 different dimers
o No costimulation w/ antigen presenting cells = unresponsive T cell
Requires both in order to be responsive
o 3 types of signal that vary that change the T cell phenotypes
Cytokines
IL10 secreted by macrophages/dendritic cells = suppressed IL12
= T reg phenotype
IL10 low = high IL12 = Th 1 phenotype
Amount of MHC varies
High levels of MHC/costimulation = Th1 cells
Low MHC/constimulation = Th2/reg cells
Accessary constimulation varies
Activated T cell =
o High affinity to Il2 = upreg to stimulate cellular division to form multiple effector
T cells
Leads to massive clonal expansion, reduction and then memory T cell
pool
CD4 T helper cell aids
o Macrophage amplification
Pathogen killed by being activated by IFN gamma by Th1 cells
Allows fusion of lysosomes and formation of phagolysosomes
Allows production of toxic O radicals, NO and antibacterial peptides
Cytokine/chemokine release for recruit (also by activated Th1 cell)
Activated macrophages secrete TNF alpha = antimicrobial
Controlled to reduce tissue damage (bc not antigen specific)
o B cells amplify antibody response
B cell expansion due to activation from T cell because of MHC
presentation of pathogen fragment
Forms either plasma cells or memory cells
Costimulation
Signal 1 = B cell receptor recognize of epitope
Signal 2 = CD40 stim from T helper cell
Leads to expansion of B cell then antibody synth from plasma
cells
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 robbieseal. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.38. You're not tied to anything after your purchase.
