Chap 43 - Immune system Flashcards
Toll
Fungal cell wall receptors of the innate immune system in invertebrates.
Toll-like receptors (TLR)
Mammalian immune system receptors on phagocytes that detect a range of pathogens. (not just fungi)
Part of innate immune system.
Innate system cells (6)
- Neutrophils & Macrophages
- Dendritic cells
- Eosinophils
- Natural killer cells
- Mast cells
Neutrophils
Smaller phagocytic cells that travel in blood and are attracted to sites of infection.
Dendritic cells
In tissues that are in contact with the environment (eg. skin).
Stimulate adaptive immunity - very good antigen-presenting cells.
Eosinophils
Found below epithelial cells.
Deals with multicellular invaders.
Natural killer cells
Detect infected cells and activate programmed cell death.
Mast cells
Found in connective tissue. Stimulates inflammation through histamines.
Lysozyme
Enzymes that break down cell walls of pathogens.
Haemocytes
Major immune cells in Arthropods.
Phagocytic. (they dont have adaptive immune systems)
Lymphocyte
A class of white blood cell that mediates immune responses.
Natural killer cells, B cells & T cells.
Antigen
Something that binds to the receptors on B cells/T cells and thus stimulates a response.
Epitope
The small region on an antigen that binds to receptors.
Multiple antibodies can bind to different epitopes on the same antigen.
B cell receptor components
- Two identical heavy chains.
- Two identical light chains.
- Connected by disulphide bridges.
Variable (V) region
The regions on receptor chains that vary a lot between different B cells/T cells, and create binding sites for antigens.
Constant (C) region
The regions on receptor chains that are pretty much the same for all B cells/T cells, mostly it just anchors the receptor to the cells and takes care of the structure.
T cell receptor components
- An alpha and a beta chain, with binding site made of the ends of both.
- Again linked by disulphide bridges.
Major histocompatibility complex (MHC)
A complex that binds with antigen fragments within a cell, where it will then present the foreign antigen on the cell’s surface “like a bun holding a hotdog”.
T cells only bind to antigens presented on MHCs.
Effector cells (in immune system)
An ‘active’ lymphocyte that is born of a cloning B cell or T cell after its receptor is triggered by an antigen.
B cell effector form
Plasma cells that produce antibodies, short lived.
T cell effector form
Helper T cells & cytotoxic T cells.
Memory cell
A clone of a B cell or T cell that can quickly differentiate into effector cells if the same antigen is encountered again.
Primary immune response
Upon exposure to an antigen for the first time; antibodies are produced in smaller numbers and peak 10-17 days after exposure.
Secondary immune response
Upon later exposures to the same antigen; antibodies are produced faster and in larger quantities, peaking just 2-7 days after exposure.
