Basic Principles Flashcards
What is the function of IgG? What is it’s frequency in the body?
75%
- enhance phagocytosis
- fixes complement and passes to the fetal circulation
- most abundant isotope in blood serum
What is the function and frequency of IgA?
15%
- IgA is the predominant immunoglobulin found in breast milk found in secretions of digestive, respiratory and urogenital tracts
- most commonly produced but not most abundant
- transported across the interior of the cell via transcytosis
What’s the function and abundance of IgM?
10%
- First immunoglobulin to be secreted in response to infection
- Fixes compliment but doesn’t pass to the fetal circulation as could result in haemolysis
- Anti-A, B blood antibodies
What is the function of IgD and its frequency in the body?
1%
- Role in the immune system largely unknown
- Involved in the activation of B cells
What’s the frequency and function of IgE?
- 1%
- Mediates type 1 hypersensitivity reactions
- Binds to Fc receptors found on the surface of mast cells and basophils
- Provides immunity to parasites such as helminths
- Least abundant isotype in blood serum
What does the CD1 cell surface marker do?
MHC molecule that presents to lipid molecules
CD2 cell marker does what in the immune system?
Found on thymocytes, T cells and some natural killer cells that act as a ligand for CD58 and CD59 and is involved in signal transduction and cell adhesion.
What does CD3 cell markers do?
The signalling component of the T cell receptor complex
What do CD4 cell markers do?
Found on T-helper cells.
Co-receptor for MHC class two
Used by HIV to enter T cells
What’s the role of CD5 cell marker in immunity?
Found in the majority of mantle cell lymphomas
What’s the function of a CD8 cell marker?
Found on cytotoxic T cells
Co-receptor for MHC class one
Found on subset of myeloid dendritic cells.
What’s the function of cell marker CD14 15 and 16?
14 is the cell surface marker for macrophages
15 is expressed on read Sternberg cells
16 find to the FC portion of IgG antibodies
What are complement proteins?
Compliment is a series of proteins that circulating the plasma and are involved in infantry and immune reactions of the body. E.g. chemotaxis, cell lysis and opsonisation.
What is the classical compliment pathway?
Initiated by antigen Antibody complex’s. (IgM/IgG)
C1qrs, C2, C4
What’s the alternative compliment pathway?
Initiated by polysaccharides for example gram negative bacteria, also IGA.
C3, factor B, properdin
What is the function of Interleukin-1 and interleukin-2?
1- Mainly sourced from macrophages it causes acute inflammation and induces fever.
2- Mainly sourced from TH1 cells it stimulates growth and differentiation of T-cell response.
What is the role of interleukin-3 and 4?
3- Mainly produced by activated T-helper cells it stimulates differentiation and proliferation of myeloid progenitor cells.
4- Produced by TH to cells stimulates proliferation and differentiation of B cells
What is the role of interleukin five and interleukin-6?
5- Produced by TH to cells it stimulates production of eosinophils
6- Produced by TH to cells it’s stimulates differentiation of B cells and induces fever
What is the role of interleukin 8, 10 and 12?
8- Produced by macrophages it induces neutrophil chemotaxis
10- TH2 cells mainly produce it and it inhibits Th1 cytokines synthesis
Known as the anti-inflammatory cytokine
12- mainly sourced from macrophages and B cells. It activates NK cells and stimulates differentiation of naive T cells into Th1 cells.
What do you helper T cells do in adaptive immunity?
Involved in the cell mediated immune response.
Recognises antigens presented by MHC class II molecules.
Expresses CD4
Also expresses CD3, TCR and CD28.
Major source of interleukin-2.
Mediates acute and chronic organ rejection.
What’s the role of cytotoxic T cells in adaptive immunity?
Involved in the cell-mediated immune response.
Recognises antigens presented by MHC class I molecules.
Induces apoptosis in virally infected tumour cells.
Expresses CD8
Also expresses CD3, TCR
Mediates acute and chronic organ rejection.
What’s the roll of a B cell in adaptive immunity?
Major cell of the humoral immune response.
Act as an antigen presenting cell.
Mediates hyperacute organ rejection.
What’s the role of a plasma cell?
- Differentiated from B cells
- Produced large amounts of antibody specific to a particular antigen.
What’s the role and properties of a neutrophil?
- primary phagocytes cell in acute inflammation.
- granules contain lysozyme
- most common type of white blood cell.
- multi-lobed nucleus
What’s the role of a basophil?
- to release histamine during an allergic response.
- granules contain histamine and heparin
- Expresses IgE receptors on the cell surface
- Bi-lobed nucleus.
What’s the role of a mast cell?
- Release histamine during an allergic response.
- Granules contain histamine and heparin
- Expresses IgE receptors and the cell surface.
What is an Eosinophil?
Defends against protozoan and helminthic infections with a bi-lobed nucleus.
What is a monocyte?
Differentiates into macrophages
Kidney shaped nucleus
What’s the role of a macrophage?
- Involved in phagocytosis of cellular debris and pathogens.
- Acts as an antigen presenting cell.
- Major source of IL-1
What’s the role of a natural killer cell?
Inducing apoptosis in virally infected and tumour cells
What is a dendritic cell and what’s its role?
Acts as an antigen presenting cell.
What are some innate immune barriers?
Skin,
gut - low PH - enzymes pepsin
Lungs - pulmonary surfactant
Eyes/nose/oral cavity- tears, Cillia, enzymes in saliva
What are non-specific defences of the innate immune system?
Defensins, compliment and Toll like receptors
What are toll like receptors?
- found on sentential cells
- recognise PAMPS
- Stimulate the immune response.
What is a defensin?
- cationic proteins/peptides
- disrupts membranes and viral envelopes
It will form a pore in the membrane - disrupts metabolic process’
What cell bridges the innate and adaptive immune system.
A dendritic cell
What do dendritic cells do?
- Phagocytise pathogens via TLR’s
- Present and display antigens
- activate other immune cells
What are the two adaptive defences?
- cell-mediated
- humoral
Where do T cells develop?
The thymus
What do CD8 T-cells do?
Selectively recognise molecules bound to MHC-1 and self receptors.
Directly destroy infected cells.
What do CD4 T-cells do?
Helper cells that modulate other immune responses through activation and deactivation via MHC-2 receptors.
What are MHC class 1?
- Found on most cells
- display peptides generated from intracellular cytosolic proteins
What are MHC class 2?
- only found on professional antigen presenting cells
- derived from extracellular proteins
- regulates how other immune cells respond to infection.
