hello quizlet
Home
Subjects
Expert solutions
Create
Study sets, textbooks, questions
Log in
Sign up
Upgrade to remove ads
Only $35.99/year
Science
Biology
Immunology
Immunity lecture 2
Flashcards
Learn
Test
Match
Flashcards
Learn
Test
Match
Terms in this set (25)
Purpose of positive and negative selection?
To educate T cells and get rid of the ones that present self!
Clonal selection vs clonal expansion
clonal selection picks the T cell receptor that can recognise the antigen and clonal expansion will make lots of them for an effective response
HLA and relationship to MHC?
How does MHC achieve diversity
Human leukocyte antigens is a gene encoding for different types of MHC (major histocompatibility complex)
- VDJ re-arrangment
What kind of things must be presented to a TCRs in order for them to recognise an antigen?
What else is needed for recognition?
peptide antigen and must be presented on MHC
costimulation by CD4 and CD8
Killer T cell recognise what class (encoded by?) Helper T cells recognise what class (encoded by?)?
MHC-1 (HLA A B C)
MHC- 2 (HLA DR DP DQ)
What kinds of cells can CD8 T cell recognise? What kind of cells have this type of MHC?
What about CD4?
How does 1 get selected over the other or not?
MHC class 1- all nucleated cell! (only intracellular parasites or virsuses, these will be broken down by proteosomes into peptide fragments that are loaded onto MHC 1 from the ER)
MHC class 2- can only bind to professional antigen presenting cells (These are exogenous sources that are phagocytosed and combined with the receptor which is made by the endoplasmic reticulum)
In the thymus, once the cells bind to one type, the other will be downregulated!
Do antigen presenting cells and nucleated cells present all MHC molecules that should be on them? What kind of inheritance?
Yes. It is co-dominant inheritance where the person will get the MHC from their mother and their father!
- Co dominant!
What are 3 signals for naive T cells receiving from DC?
1) Peptide antigen on MHC2 with CD4 since this is a interaction between APC and T cell
2) Co-stim molecules (CD80 and CD86 from the APC and CD28 from the dendritic cell)
3) Cytokines released by the APC which will direct the type of T cell which is made!
Are helper T cells CD4 or CD8? What kind of T cells are presented to? What kind of MHC do they respond to?
CD4 and MHC 2
naive!
What do you call T helper cells which help B cell proliferation?
follicular helper T cells
T helper 1 cells will
secrete?
stimulating?
diseases?
What stimulates it?
IFK gamma
macrophages
salmonella and TB
It is stimulated by IL12 and IFN gamma
T helper 2 cells will
secrete?
stimulating?
diseases?
What stimulates it?
IL4, IL5 and IL13
eosinophils, mast cells and plasma cells
parasitic, helminth or worm
It is stimulated by IL4
T helper 17 cells will
secrete? that act on?
stimulating?
what stimulates it?
IL17 to fibroblasts and epithelial cells which then releases chemokines
neutrophils
TGF beta and IL6
T follicular helper cells
Act on? causing?
Where are these cells located?
What stimulates it?
B cells! proliferation through plasma cells along with isotype switching and affinity maturation
- spleen and the lymph nodes
- IL6
T reg
Do what?
What stimulates it?
Inhibit dendritic cells from presenting antigens to T cells, stops proliferation of autoreactive cells
TGF beta
How does a T helper cell help macrophages?
A helper T cell which is activated in the lymph node will migrate towards the site of infection. There is will encounter macrophages, upregulate CD40 ligand (binds to CD40) and release interferon gamma which binds to the IFN receptor. This causes the macrophage to kill its contents such as TB or salmonella
What surface molecules do regulatory T cells express?
What do they secrete?
CD25 and FOXP3
They secrete IL10 and TGF beta (anti-inflam) which generally will dampen the immune system effects
What do you get with a mutation in FOXP3?
IPEX!
How do CD4 cells and APCs help the production of killer T cells?
CD4 T cells will upregulate CD40L which will bind to CD40 on the APC. This causes CD4 cells to release IL2 to the CD8 cell and also produce internal signals to activate the CD8 T cell through the APC
In terms of cytotoxic T cell function, how does perforin work?
What are granzymes and what do they do?
Perforin will insert pores so that granzymes can be inserted. They are serine proteases that will cause cell apoptosis!
What kind of thymocytes do natural killer T cells develop from?
Double positive thymocytes
What is unique about the TCR of natural killer cells?
What is their role?
They are restricted to CD1d which recognises lipid antigens
They will produce alot of IL4 and IFN gamma
Where do gamma delta T cells develop? Do their receptors have much diversity?
They develop in the thymus and express gamma delta which have limited diversity
Where are gamma delta T cell located and what do they produce?
Usually in epithelial tissues between cells
- they produce cytokines!
Describe time to induce adaptive immunity and response rate
Adaptive immunity takes longer to establish but when it does, the response is faster and greater