Questions from immunology overview Flashcards
Which interleukin promotes a common lymphoid progenitor to develop into a NK cell in the bone marrow?
IL-13
Which interleukin promotes a common lymphoid progenitor to develop into a T cell in the bone marrow?
IL-7
What 2 processes do common lymphoid progenitor cells undergo before development into either Naive T or B cells?
1) (random) Antigen receptor VDR rearrangement
2) negative selection (to detect inappropriate self binding –> autoimmunity, to detect for affinity to individual HLA for T cells, can bind but not too strongly)
What is the role of AIRE?
Autoimmune Regulator
Genes which allow the expression of peripheral proteins in the thymus–> developing T cells are exposed and therefore reduces chances of autoimmunity eg small amounts of insulin are made in the thymus!
Where can you find T cells expressing both CD4 and CD8 receptors?
Thymus
Which cells function as antigen presenting cells (APCs)?
Dendritic cells
Macrophages
B cells
What is the role of dendritic cells in the immune system?
Recognise foreign antigen Phagocytose Break down into peptides Travel to lymphoid tissue to present peptide on MHC Also up regulate costimulatory molecules
What costimulatory mechanism is important for CD4 T cell interactivation with APC ( acting with the TCR - MHC Class II interaction )?
CD 28 on the T cell with B 7 on the APC
Which interleukin (secreted by activated T cells) promotes T cell proliferation?
IL-2
Which cytokines promote the development of Th17 cells?
TGF beta
IL-6
IL-1
Which cytokines promote the development of Th2 cells?
IL-4
Which cytokines promote the development of Th1 cells?
IL-12
Which cytokines promote the development of Treg cells?
TGF beta
IL-10
What costimulatory mechanism is important for CD4 T cell interactivation with B cell ( acting with the TCR - MHC Class II interaction )?
CD 40 on the B cell
CD 40 ligand on the T cell
What happens in the germinal centres?
Activated naive B cels travel here (to the lymph node)
Purpose is to randomly generate a better fit antibody for the antigen (affinity maturation)
And produce that antigen (isotype switching)- IgG has a higher affinity for antigen than IgM
Generate memory B cells and plasma cells (generally migrate to the marrow)
What are the 3 pathways to activate the complement cascade?
Lectin- mannose binding lectin acts as a kind of “universal antibody” and activates the cascade
Alternate- complement recognition of a surface as foreign –> coating
Classical- immunoglobulin coating of a pathogen noticed and activated by C1q
What is the common point in all 3 pathways of the complement cascade?
C3–> C3b
Results in opsonisation OR induces C5-C9 (MAC)
Which cytokines are secreted by Th2 cells in response to antigen presentation, and what is the cellular response to the signals?
IL-4 and IL-13 activate B cells to produce IgE
IL-5 secreted to activate eosinophils (recognize the IgE on a pathogen)
What is thought to be the evolutionary purpose of the Th2- eosinophilic interaction?
Fight helminth infections- eosinophils are designed to fight pathogens that are not able to be phagocytosed
Which cytokines are particularly involved in inducing a systemic inflammatory response?
IL-1
IL-6
TNF
What is the role of Th2 cells in the allergic response?
Th2 detects antigen (from an allergen) presented by an APC
Induces production of IgE to the allergen by B epsilon cells/plasma cells (secretion of IL-4, IL-13)
IgE on the allergen surface is the detected by the mast cells and results in
1) stored mediator release (eg histamine)
2) manufacture of mediators (eg leukotrienes)
3) release of chemokines and cytokines to induce a late phase response by monocytes, neutrophils, T cells and eosinophils
Which cytokines secreted by Th17 cells promote chemokines to be secreted by somatic cells?
IL-17
IL-22
How do NK cells induce antibody-mediated cell-independant cytotoxicity?
Viral antigen expressed on the cell membrane
Targeted by IgG
FcgammaR on NK cell recognises antigen
Induces a lethal hit (perforin, granzyme, Fas, TNF)
How do NK cells induce antibody-mediated cell-dependant cytotoxicity?
Virus/tumour down regulates MHC expression
MHC inhibitory signal not received by NK cell, activatory co-signal recieved
–> Lethal hit
How do CTLs induce cytotoxicity due to cell processing of internal antigen, ie monitor the intracellular environment?
All somatic cells are processing both internal pathogenic and self-proteins constantly and present on the cell surface on MHC1 for CTL detection
CTL approaches MHC1 with TCR, if protein foreign or indicates need for apoptosis
–> Lethal hit
Which cytokine is most responsible for fever?
IL-1
Which cytokines are released by cells undergoing apoptosis?
IFN-alpha
IFN-beta
Which cells mediate the activity of cytotoxic T lymphocytes?
Treg cells
